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6.3.2 Single-delivery request routing
Figure 6.3.2.1 shows the procedure for request routing for a single content-item delivery. Figure 6.3.2.1: Single-delivery request routing The procedure has the following steps: 1) The uRCF is triggered to initiate request routing, e.g. by an incoming content delivery request from a User Equipment (UE). 2) The uRCF send a request to the dRCF, with a contentID and optionally information (e.g. location or IP address) of the UE to which the identified content is intended to be delivered. 3) The dRCF may select a dDCF. It may communicate about this with the selected uDCF. NOTE 1: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 4) The dRCF sends a response to the uRCF, with the dDCF address to which the UE content delivery request should be redirected. NOTE 2: No assumptions are made how that redirection takes place in the Upstream CDN domain. It may use HTTP redirect, DNS response, combination of both, or other.
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6.3.3 Multiple-delivery request routing
Figure 6.3.3.1 shows the procedure for request routing for multiple content items simultaneously. This procedure increases efficiency when there is a high intensity of request routing between the uCDN and dCDN. A specific case is segmented content, where the uCDN wants to fill-in a manifest file (MF) for directing individual segment requests directly to the proper dDCF. As the resulting MF, filled-in by the uCDN, is typically relatively small and UE-specific, it could be delivered to the UE by the uCDN directly, instead of having the MF delivered by the dCDN. 2. 4. 3. dDCF uRCF dRCF uDCF 1. Trigger ETSI ETSI TS 182 032 V1.1.1 (2013-04) 26 Figure 6.3.3.1: Multiple-delivery request routing The procedure has the following steps: 1) The uRCF is triggered to initiate request routing, e.g. by an incoming content delivery request from a User Equipment (UE) for segmented content. 2) The uRCF sends a request to the dRCF, with multiple contentIDs and optionally information (e.g. location or IP address) of the UE to which the identified content items are intended to be delivered. 3) The dRCF may select one or multiple dDCF(s) for the content delivery. It may communicate about this with the selected uDCF. NOTE: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 4) The dRCF sends a response to the uRCF, with the dDCF address(es) to which the UE content delivery request should be redirected for the different identified content items. The uCDN can use this information for UE redirection and/or for filling in an MF.
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6.4 Reporting
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6.4.1 General
The reporting between CDNs is realized by two different procedures. The differences between them are explained below: • Upstream-initiated reporting is used by the upstream CDN to retrieve any information from the downstream CDN. This information may include up-to date delivery statistics and status , comprehensive historical logs or other information. The structure of these reports is not strictly defined by the present document. It only provides a way for the uCDN to inform the dCDN about the kind of data that it requests. • Downstream-initiated reporting is used when a downstream CDN needs to immediately inform the upstream CDN about a recent event related to a specific content item. The format and contents of these reports are strictly defined by the present document.
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6.4.2 Upstream-initiated reporting
The main role of the upstream-initiated reporting procedure is to make it possible for the uCDN to get access to the content-related information gathered by the dCDN while delivering the content to clients. This procedure shall be initiated by the uRCF to inform the dRCF about the fact that the uRCF requests specific information. The request sent by the uRCF shall include the description of the type of information required. Depending on the nature of the information the dRCF shall either respond either by directly returning the requested information or it shall return a URL that the uRCF will be able to use to access the requested information. This procedure is visualized in figure 6.4.2.1. 2. 4. 3. dDCF uRCF dRCF uDCF 1. Trigger ETSI ETSI TS 182 032 V1.1.1 (2013-04) 27 Figure 6.4.2.1: Upstream-initiated reporting procedure The procedure consists of following steps: 1) The uRCF sends a report request to the dRCF. This request indicates the description of information that the uRCF requires. 2) The dRCF shall respond to the uRCF with either the required information, or information about where it can be obtained. 3) The uRCF shall acknowledge the reception of the response.
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6.4.3 Downstream-initiated reporting
The role of the downstream-initiated reporting procedure is to inform the uCDN about a content-related event that happened within the dCDN. This procedure is visualized in figure 6.4.3.1. Figure 6.4.3.1: Downstream-initiated reporting procedure The procedure consists of following steps: 1) The dRCF sends a report message to the uRCF. 2) The uRCF shall acknowledge the reception of the report message.
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6.5 Interconnection Control Function Procedures
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6.5.1 General
These procedures allow to inform the uCDN about changes of specified capabilities/footprint/status of a dCDN. The information contained in these updates shall match the data models defined in clause 7. Examples of specific messages can be found in annex B. 1. Report request uRCF dRCF 2. Report response 3. Report ack uRCF dRCF 1. Report message 2. Report ack ETSI ETSI TS 182 032 V1.1.1 (2013-04) 28
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6.5.2 Capabilities exchange
The capability exchange is a procedure whose main goal is to inform the uCDN about the capabilities of a dCDN. The capability list is a data structure describing the list of capabilities (or features, services and their parameters) that the dCDN is willing to provide to uCDN. The capability exchange procedure is primarily used to exchange information about CDN capabilities over CDN interconnection. It can also be used for exchanging information about capabilities related to content delivery. These capabilities description are used to achieve interoperability between the CDNs compliant with the present document and enable interconnection with other CDNs that support just a subset or different sets of capabilities (e.g. comply only with basic capabilities specified in the IETF CDN-I standards [i.2]). If there is a CDN that does not support one of the methods of content delivery for example HTTP, it will still be able to interconnect and provide the delivery of content using other delivery methods that it does support, and will just need to communicate its capabilities over the capability exchange. For this reason CDNs compliant with the present document shall understand the meaning of the identifiers that represent these capabilities. Figure 6.5.2.1: Capability Exchange The capability exchange procedure is always initiated by the dCDN sending information about its capabilities to the uCDN. It consists of following steps: 1) The dCDN sends a capability message to the uCDN. This message contains the list of capabilities describing the dCDN. Examples of possible capabilities can be found in clause B.1 Metadata structure. 2) The uCDN acknowledges the reception of the capability message by sending a capability acknowledgement.
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6.5.3 Footprint exchange
The footprint exchange is a procedure whose main goal is to inform the uCDN about the footprint of a dCDN. The footprint is a data structure containing a list of network segments for which the dCDN can deliver content items for the uCDN. There are multiple methods that can be used to describe a network segment. The most basic one is an IP prefix. An IP prefix is a network number accompanied by a prefix length number. Geolocation, AS numbers and others are also viable candidates for network segment definitions. The basic rule is that any segment description can be used as long as there is a definitive agreement between the interconnected CDNs about how to map them to IP addresses. uICF dICF 1. Capability message 2. Capability acknowledgement ETSI ETSI TS 182 032 V1.1.1 (2013-04) 29 Figure 6.5.3.1: Footprint Exchange The footprint exchange procedure consists of following steps: 1) The dCDN sends a footprint database update to the uCDN. This message is triggered by a change of the footprint that dCDN wants to serve for uCDN. The update message contains only the changes from the previous version of the database and a checksum of the full database it is supposed to converge to after merging with previous version. 2) The uCDN merges the update with its footprint database related to the dCDN, calculates its checksum and compares it to a checksum received as part of the update message. If the checksum is ok then it skips over to step 5, otherwise it proceeds on step 3. 3) The uCDN requests the full footprint database from the source CDN. The full footprint database contains the whole data structure containing information about dCDN's footprint. 4) The dCDN sends the full footprint database to the uCDN. 5) The uCDN confirms the reception of the footprint update or database by sending a footprint exchange acknowledgement message. The footprint exchange process can start on step 1, 3 or 4 of the described procedure. If the process is triggered by a change in dCDN footprint database then it starts on step 1. If the uCDN triggers the process then it starts on step 3. If the process is triggered as the first footprint exchange then it starts on step 4.
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6.5.4 Services status exchange
The status exchange is a procedure whose main goal is to inform the uCDN about the status of a dCDN. This procedure is specific in the fact that it can be triggered not only in reaction to a change of status in the dCDN but is also used as a keep alive mechanism. This means that even when the dCDN's status did not change it has to send a status message within a defined amount of time to let the uCDN know that the status is still valid. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 30 Figure 6.5.4.1: Service Status Exchange The status exchange procedure is always initiated by the dCDN sending information about its status to the uCDN. It consists of following steps: 1) The dCDN sends a status message to the target CDN. 2) The target CDN acknowledges reception of the status message by sending a status acknowledgement.
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6.6 DRM Procedures
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6.6.1 General
These procedures are used when the CDN interconnection is involved in the DRM for content delivery.
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6.6.2 Flagging CDN content for DRM
An uCDN can flag to a dCDN that DRM procedures should be applied for a specific content item. This is flagged during content distribution. In case of upstream-initiated content distribution, step 3 of clause 6.2.2.2 includes that DRM flag. In case of downstream-initiated content distribution, step 4 of clause 6.2.2.3 includes that DRM flag.
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6.6.3 Key exchange for DRM
These procedures are relevant if the dCDN would need to encrypt a content item for delivery to a specific UE. Different encryption for different UE provides an additional layer of protection against signal theft. The content item could be stored in plain format. There exist also DRM systems that enable the content to be stored in encrypted format, and where a key is used to re-encrypt or partially decrypt it into the UE-specific encryption without fully decrypting the content in the process. This protects the content item against content theft at the CDN.
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6.6.3.1 uCDN-initiated key exchange for DRM
Figure 6.6.3.1.1 shows the procedure for uCDN-initiated key exchange for DRM. It may be combined with the single- delivery request-routing procedure of clause 6.3.2. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 31 Figure 6.6.3.1.1: uCDN-initiated key exchange for DRM The procedure has the following steps: 1) The uRCF is triggered to perform a key exchange procedure. The trigger may be a delivery request from a UE for DRM-protected content. 2) The uRCF sends a key exchange message to the uDCF. This message contains a DRM-instruction identifier, a DRM key, a contentID identifying the content item and an identifier of the UE and/or transaction (e.g. IP address or token). The semantics of the DRM instruction identifier are bilaterally agreed between the uCDN and the dCDN. It is used to instruct the dCDN which DRM system and DRM procedures need to be applied. 3) The dRCF may communicate with one or more dDCF to pass the received information. NOTE: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 4) The dRCF returns an acknowledgement. As the triggers and procedure are similar with single-delivery request routing (clause 6.3.2), the two procedures may be combined.
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6.6.3.2 dCDN-initiated key exchange for DRM
Figure 6.6.3.2.1 shows the procedure for dCDN-initiated key exchange for DRM. If the content distribution to the dCDN has not yet taken place, then this procedure may be combined with the procedure for downstream-initiated content distribution in clause 6.2.2.3. Figure 6.6.3.2.1: dCDN-initiated key exchange for DRM 2. dDCF uRCF dRCF uDCF 1. Trigger 3. 4. 2. dDCF uRCF dRCF uDCF 1. Trigger 4. 3. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 32 The procedure has the following steps: 1) The dRCF is triggered to perform a key exchange procedure. The may be a delivery request from a UE for DRM-protected content. 2) The dRCF sends a request message to the uRCF. This message contains a contentID identifying the content item and an identifier of the UE and/or transaction (e.g. IP address or token). 3) The uRCF responds with a message that contains a DRM key and optionally a DRM-instruction identifier. A DRM-instruction identifier would be passed, if it cannot be derived from the UE request. UE requests typically contain tokens for authentication purposes, and a DRM instruction could also have been encoded in the token. 4) The dRCF may communicate with one or more dDCF to pass the received information. NOTE: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document.
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7 Data models
There are two categories of data models. 1) CDN related data models This category of data represents the information about a specific CDN network from the interconnection perspective. - CDN information contains basic data that is relevant to specific CDN. - CDN footprint defines a single footprint segment that is related to a specific CDN. - CDN capabilities describe the capabilities of a specific CDN within a specific footprint segment. 2) Content related data models This category describes the data models relevant to specific content items and their delivery. - Content related metadata data model includes all the basic information describing the content. - Content distribution reporting data model includes all the data related to the distribution status of a specific content. - Content request source data model includes all the data related to a source of content delivery request. - Content delivery reporting data model includes all the data related to delivery of a specific content. Annex D provides examples of such data models. NOTE: There were no IETF-specified inter-CDN data models available at the time of writing the present document.
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8 Security
This clause specifies all the security aspects used for CDN interconnection. Their main purpose is to make it provide a complete tool-set that can be used to make CDN interconnection into a secure environment while maintaining scalability and flexibility. Scalability is guaranteed by adhering to the architectural principles defined by the high-level architecture as described in clause 5 of the present document. It is also reinforced by the use of encryption protocols and techniques that can be easily accelerated by available hardware. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 33 Flexibility is achieved by making all the elements of CDN interconnection security optional and by not using any proprietary protocol or complicated solutions. All the technologies used are usually already implemented in production CDN environments so they will not have to be re-engineered for CDN-I environments.
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8.1 Security feature interoperability
Because all of the security features in CDN-I environments are optional it is important to define the means of interoperability between CDNs with different CDN-I security feature sets. This kind of interoperability is achieved by the means of capabilities, see clause 6.5.2. This means that every security feature is represented by a corresponding capability that is advertised to peer CDNs every time a CDN interconnection relationship is established.
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8.2 CDN interconnection service protection
The security of communication between CDN-I entities, as specified in clause 6, is achieved by using the SSL/TLS protocol to encrypt and authenticate all communication channels. In most scenarios this consists of using the HTTPS protocol instead of plain HTTP for CDN-I procedure messages. In some cases it may also mean using secure versions of content distribution protocols. The authenticity of peer party can be always reliably verified by checking the security certificate at the time of connection set-up. If the certificate is neither known nor signed by a trusted certification authority then the connection should not be established. If it is established, then it shall be considered untrustworthy. The method of establishing secure connection between two CDNs is described in clause 8.2.1.
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8.2.1 Secure CDN-I connection establishment
The establishment of a secure CDN-I connection should begin by trying to connect to the Interconnection Control Interface of a peer CDN via the HTTPS protocol, using procedures described in clause 6.1.1. If the connection can be established and the certificates are valid and considered trustworthy, then the connection between the interconnection control entities is assumed to be trusted. If it is not possible to connect to the interconnection control interface via HTTPS, then HTTP shall be used instead and the connection shall be considered untrusted. If the HTTPS connection can be achieved but the certificate cannot be verified then it can still be used but shall also be considered untrusted. The decision about whether interconnection establishment may continue even when the connection between interconnection control entities is untrusted shall be made according to a local security policy of a particular CDN (not defined by the present document). TLS/SSL contains the option of no encryption algorithm (NULL). This option shall not be used within the scope of the present document. After the Interconnection Control entities are successfully interconnected, a capability exchange takes place, see clause 6.5.2. If the capabilities of a peer CDN indicate that it can use trusted connection for communication between RCFs or DCFs then these may be bootstrapped using secured connections. If all such connections between two CDNs are established via secured protocols and all the certificates are valid then the communication between two CDNs shall be considered trusted. Secure CDN interconnection may be a requirement of a security policy of a specific CDN. It may also be a requirement of the content provider. In such scenario the content provider shall indicate this requirement by the means of a metadata parameter indicating that a specific content may only be distributed between CDNs that are interconnected via secure and trusted connections.
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8.3 CDN interconnection content and metadata authenticity
The authenticity of content and its metadata shall be achieved by protecting integrity by means of the security certificates. Content and or its metadata can be signed with a private key belonging to the content provider. The certificate and checksum generated for authenticity, generated with the use of the content provider's private key, shall be included as a part of the metadata file. Any CDN that requires verifying the authenticity of a piece of content or its metadata should have access to an authority where it can verify the certificate included in the metadata file. An example of such authority may be the DNSSEC system. It may also suffice for the certificate to be signed by the uCDN's private key (which should already be trusted at time of such check). ETSI ETSI TS 182 032 V1.1.1 (2013-04) 34
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8.4 Security policy definition by content provider
It shall be possible for the content provider to define rules related to the security requirements of the content they want to provide. These rules should be indicated within the metadata file accompanying the content. The content provider should guarantee the authenticity and integrity of this metadata file by signing it with its private key and publishing its corresponding public key in a certificate so that it can be used for verification. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 35 Annex A (informative): Interfaces and Functions This informative annex provides insight of CDN interconnection interfaces under study by other SDOs and projects. It also provides an initial list of functions that should be supported by the CDN interconnection architecture. A.1 CDN interconnect interfaces under study CDN interconnection is being studied by several SDO and projects. This clause provides insight of CDN interconnection interfaces under study by those SDOs and projects. A.1.1 ETSI CDN Figure A.1.1.1 shows the reference points of the ETSI CDN architecture (TS 182 019 [i.6]). Figure A.1.1.1: Reference points in ETSI CDN The following are the horizontal interfaces that may be relevant for CDN interconnection: • ALF - ALF (Qq'). The Asset Location Function is a functional entity having the knowledge of the available content, the content location and others content parameters. The Qq' reference point between ALFs allows one ALF to query another about the addresses having the requested content. It can be considered a subset of the Qq reference point between CDNCF and ALF. This reference point may exist between two ALFs belonging to different CDNs. • CDNCF - CDNCF (Yq). The Content Delivery Network Controller Function the function which manages one or more [CDN] clusters. The Yq reference point is used to allow a CDNCF to proxy a request to another CDNCF for handling. This reference point may exist between two CDNCFs belonging to different ETSICDNs. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 36 • CDF-CDF (Cf). Tasks of Content Delivery Function are a.o. handling content delivery. The Cf reference point between CDF and CDF allows delivering content between the two CDFs for content distribution. The CDF is always instructed where to go to acquire content. This reference point may exist between two CDFs belonging to different ETSI CDNs. A.1.2 IETF CDN-I A.1.2.1 General The published CDN Interconnection Problem Statement document RFC 6707 [i.2] provides a rationale for CDN interconnection, CDN-I terminology and a basic architecture outline. That outline provides the following four interfaces: • CDN-I Control Interface • CDN-I Request Routing Interface • CDN-I Logging Interface • CDN-I Metadata Interface The CDN-I Control Interface is used primarily for bootstrapping of all the other interfaces and exchange of the static information related to the CDN. It also includes some of the basic content control functions of the interconnection. Some of these include content purge requests and also the initiation of a content pre-positioning process. The CDN-I Request Routing Interface is responsible for ensuring that all user requests can be redirected to the most appropriate node of the CDN federation. Other than the primary role of handling client request redirects, it also handles the exchange of CDN-I information needed to properly make the request routing decisions. The CDN-I Metadata Interface is responsible for proper distribution of content related metadata. This metadata may contain informative data related to the content but also technical rules that should be considered when the files are being delivered. The CDN-I Logging Interface is responsible for correct distribution of any logs and reports related to the delivery of the client from the dCDN to the client. A.1.2.2 IETF CDN-I compatibility with ETSI CDN-I This clause discusses compatibility between RFC 6707 [i.2] and the present document. As both the IETF specifications on CDN interconnection, and the ETSI ones are work-in-progress at the time of writing the present document, all statements in the present clause about mutual compatibility have an ephemeral nature. At the architectural level, the following mappings can be made. • The CDN-Ic reference point for interconnection control from the present document seems to map on the union of the CDN-I Control Interface and the CDN-I Logging Interface from RFC 6707 [i.2]. • The CDNr reference point for request routing and content distribution control from the present document seems to map on the CDN-I Request Routing Interface and CDN-I Metadata from RFC 6707 [i.2]. There are some mismatches, as the present document distinguishes content-item specific status reporting from generic logging, whereas RFC 6707 [i.2] has a single logging interface. There are differences in terminology. The term "metadata" in RFC 6707 seems to correspond to [data for] "content distribution control" in the present document. The term "acquisition" in RFC 6707 [i.2] seems to correspond to "content exchange" in the present document. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 37 A.1.3 ATIS CSF ATIS document 0200003 [i.3] provides CDN interconnection use case specification and high-level requirements. The document contains a picture showing the following interfaces between two carrier CDNs: • Operations & Customer Care: SLA/outages/ticketing/Special customer requests. • Back-Office: Provisioning, Logs, settlements. • Routing: Traffic distribution, load management, AMT Relay address. • Delivery: Features, Capacity reservation, Origin access, multicast sources/groups. • Network Interconnection: Access, Security. The ATIS document does not specify details of those interfaces. A.1.4 FP7 OCEAN The FP7 OCEAN project (http://www.ict-ocean.eu/) is studying among others CDN interconnection. A.2 Functionality of the CDN interconnection TS 102 990 [1] specifies use cases and requirements for CDN interconnection. This clause highlights some of the requirements to start architecture discussions. A.2.1 Content distribution, upstream or downstream initiated Mechanism(s) will be needed to control the movement content from the Upstream CDN to the Downstream CDN. Content movement can be initiated by either party: • Upstream CDN initiated: e.g. triggered by the Content Service Provider, the Upstream CDN may pre- provision (specific delivery servers of) the Downstream CDN with specific content. • Downstream CDN initiated: e.g. triggered by the first Consumer request for a specific content or by a cache miss, the Downstream CDN pulls the retrieves the content from (a specified origin server of) the Upstream CDN. Preferably, the mechanisms to do this are identical or very similar. Figure A.2.1.1 is an example of an inter-CDN content distribution flow. The dotted lines in the figure are CDN-internal flows, which are outside the scope of the present document. Most likely, a mechanism should be added for confirming that the distribution of content has taken place successfully. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 38 Figure A.2.1.1: Example of an inter-CDN content distribution flow A.2.2 File-based and stream-based content The CDN interconnection should support both file-based (e.g. content-on-demand) and stream-based (e.g. broadcast) content. This will lead into differences in content distribution and reporting. • File-based content has a specified end: - So the successful distribution of the full content can be signalled. - Reporting can be done on a per-file basis. • Stream-based content does not have a pre-determined end: - So only the successful set-up of publication points for stream relay can be signalled. - Reporting may be different. Adaptive streaming is a special case, as the content is file based, but the content does not need to have a pre-determined end, as the manifest file may be updated on a regular basis. It was also recognized by IETF WG CDN-I that adaptive streaming needs special attention. Multicast in the Downstream CDN may be another special case. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 39 A.2.3 Request routing, per request or not Both IETF and ATIS present a request-routing interface to ensure that the Downstream CDN can handle specific content delivery requests. The interface could be used on a per-user request basis, but that would be potentially inefficient and delay prone. It could also be used to exchange information for a group of requests, which is equivalent to a capability exchange. Effectively, this could be some sort of resource reservation by the Upstream CDN on (servers of) the Downstream CDN. A point of discussion is the level of detail that the interface can or should provide. Can the Upstream CDN for example reserve a specified amount of storage and streaming capacity in a specific Downstream CDN server? A.2.4 Reporting or logging Clause 6.8 of TS 102 990 [1] contains several requirements on pushing and pulling content status reports and transaction reports, and monitoring of on-going content delivery. Two approaches are possible: • Logging: specify only an interface and/or messages to exchange unprocessed log files. • Reporting: also specify (extensible) datamodel(s) for the summarized status and transaction reports. The former approach is the simplest and most detailed, whereas the latter approach is more rigorous and has a better separation of concerns. Especially in case of adaptive streaming, the former approach can lead to excessively sized log files. A.2.5 Security mechanisms TS 102 990 [1] requires security mechanism for among others: • Verification of the integrity of the content (unchanged, unmutilated) • Authentication of the content source • Authorization of content requests by Consumers - In particular, an "anti-deep-linking" mechanism is required • DRM-related requirements A.2.6 Content adaptation Content adaptation has been discussed in detail by IETF, resulting in a decision that IETF CDN-I rel.1 will not support content adaptation in any form. As TS 102 990 [1] has specified requirements on content adaptations, mechanisms are needed to support it. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 40 Annex B (informative): Datamodel analysis B.1 Metadata structure B.1.1 General Metadata represents any data that is related to a content and used by the CDNs in order to distribute it properly and effectively. This clause lists all the data that can be distributed using Metadata Exchange and groups it into several categories. B.1.2 CDN Blacklists/Whitelists This group of metadata includes the information about which CDNs can the content be distributed to. It indicates weather the content can be distributed to any CDN, any CDN but those listed in a blacklist or only those CDNs listed in a whitelist. B.1.3 Capabilities required for content delivery This group of metadata lists the capabilities that a CDN is required to have in order to be allowed to deliver the content. Such capabilities can be: • Delivery protocol support (HTTP, RTSP, RTMP, MMS/RTSP and others). • Delivery format support (HTML, WMV, H.264, AAC, FLV, MP3 and others). • Data protection support (HTTPS, Tokens, content access lists and others). • Delivery method support (multicast, unicast and others). B.1.4 Content Access Lists Content access lists are metadata that define which clients can the content be delivered to. It is a list structure very similar to standard network access lists starting with several rows of allow or deny statements and ending with a deny all or allow all statement. These statements have to be evaluated by the delivery node in order to decide whether a client request is to be honoured or not. There are multiple methods by which clients can be identified within the access lists. Some of them can be IP prefixes (whole networks or hosts), country identifies (matched to IPs using geo location), cookies, https credentials and others. B.1.5 Content Manipulation Policy This clause of metadata includes information about how can the content be manipulated by the CDN before it is delivered. Some of these parameters can be: • Ability to use specified delivery protocol. • Ability to use specified delivery format. • Codecs that can be used to reformat the content. • Codec parameters to be honoured: - Resolutions allowed. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 41 - Bandwidths allowed. - Key Frame frequencies allowed. - Others. • Ability to use specific delivery method. • Ability to re-encrypt content to different encryption. B.1.6 Multi-Segment related metadata This clause of metadata includes information related to content that is a segment of a larger group. This information can include: • Unique content group identifier. • A link to a manifest related in which the segment is linked. • Identifier of previous segment. • Actual segment number. • Identifier of next segment. • Total segment count. B.1.7 Security and DRM related metadata This clause contains security related data. Some of this data can include: • Certificates proving content originality. • Certificates and keys related to encryption functionality. • Certificates used for https authorization. • Checksums used to verify data integrity. • Certification authority certificates. B.1.8 Reporting related metadata This clause lists information about which logs and other information should be gathered when delivering the content. This metadata can indicate: • The need to format reports in a defined way. • The need to include specific information in the reports. • The need to send (or upload) reports directly to specified destinations. • The need to transfer reports in a specific way. • The need to encrypt reports using a specific method/key. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 42 Annex C (informative): Scenarios for using CDN-I procedures C.1 General Clause 6 of the present document specifies a set of independent procedures for CDN interconnection. This annex provides some examples how procedures can be used in combination to achieve different types of CDN interconnection. Clause C.2 describes the basic life-cycle of an interconnection between two CDNs. Clauses C.3, C.4 and C.5 describe multiple alternatives representing actual content delivery. They differ by the level of control and reporting that the CDNs are willing to exchange. C.2 Basic CDN Interconnection life-cycle In this scenario an interconnection is established between a uCDN and a dCDN. This interconnection is then used to deliver dCDN footprint and capability information to the uCDN and to bootstrap the other required interfaces. These are then used to distribute content to the dCDN. From that point the client requests can be redirected to the dCDN. As the dCDN completes client requests it gathers logs and reports describing the delivery process of specific pieces of content. It uses the request and content control interface to deliver this information back to the uCDN. In the end the uCDN initiates the termination of the CDN-I interconnection. The dCDN completes all outstanding client requests, delivers all related reporting information and terminates the interconnection. Figure C.2.1 describes this scenario through procedures. It lists the procedures in chronologic order and assigns them to the CDN that initiated their execution. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 43 Figure C.2.1: Scenario basic CDN interconnection life-cycle C.3 Premium delivery of content Figure C.3.1 shows a procedure scenario aimed at premium delivery of content. The uCDN (on behalf of the Content Provider) is in full control of each individual delivery. The uCDN uses the upstream-initiated content distribution procedure (clause 6.2.2.2) to distribute content to the dCDN, and it waits until the dCDN confirms that it has fully received the content item. From that point, for each user request, the uCDN checks with the dCDN whether it can deliver the identified content item at the agreed quality, and it subsequently directs the user request to dCDN. The uCDN also requests the dCDN for reporting on the delivery of the content item to that user. This scenario is appropriate when the Content Provider requires for control of the premium content delivery. dCDN uCDN Footprint exchange, see clause 6.5.3 Interconnection establishment, see clause 6.1.1 Upstream-initiated content distribution, see clause 6.2.2.2 Repeat Bootstrap remaining interfaces Capability exchange, see clause 6.5.2 Downstream-initiated content distribution, see clause 6.2.2.3 OR Content exchange, see clause 6.2.3 Single-delivery request routing, see clause 6.3.2 or Upstream-initiated content deletion, see clause 6.2.2.4 Downstream-initiated content deletion, see clause 6.2.2.5 OR Upstream-initiated reporting, see clause 6.4.2 Downstream-initiated reporting, see clause 6.4.3 OR Interconnection release, see clause 6.1.3 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 44 Figure C.3.1: Scenario for premium delivery of content. C.4 Managed delivery of content Figure C.4.1 shows a procedure scenario aimed at managed delivery of content. The uCDN (on behalf of the Content Provider) uses the CDN-I interfaces to manage the dCDN selection, but it relies on the dCDN for the quality of experience for actual delivery. On a regular basis, the uCDN receives footprint information from the dCDN. The uCDN directs delivery requests from a user to a dCDN that is selected on basis of footprint information (and possibly also other information, like capabilities). Upon a cache miss, the dCDN performs a downstream-initiated content distribution to get the to-be-delivered content in real time. The dCDN decides what and when to report to the uCDN. This scenario is practical when the uCDN and the dCDN have a high-speed link to quickly handle cache misses. Figure C.4.1: Scenario for managed delivery of content dCDN uCDN Downstream-initiated content distribution, see clause 6.2.2.3 Footprint exchange, see clause 6.5.3 Direct delivery request from user to dCDN Repeat Downstream-initiated reporting, see clause 6.4.3 dCDN uCDN Single-delivery request routing, see clause 6.3.2 Upstream-initiated content distribution, see clause 6.2.2.2 Delivery request from user Repeat Upstream-initiated reporting, see clause 6.4.2 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 45 C.5 Best-effort delivery of content Figure C.5.1 shows a procedure scenario aimed at best-effort delivery of content. In this scenario, the uCDN just directs delivery requests from its users to the dCDN without any previous checks or content distribution. Upon a cache miss, the dCDN performs a downstream-initiated content distribution to get the to-be-delivered content in real time. This scenario is practical when the uCDN wishes to fully rely on the dCDN for delivery. Figure C.5.1: Scenario for best-effort delivery of content dCDN uCDN Repeat Downstream-initiated content distribution, see clause 6.2.2.3 Direct delivery request from user to dCDN ETSI ETSI TS 182 032 V1.1.1 (2013-04) 46 Annex D (informative): Datamodels This annex presents examples of data models that may be used for CDN interconnection. It represents a set of data that is sufficient to properly keep all the states required for execution of all the basic procedures described in clause 6 of the present document. D.1 CDN related data models This category of data represents the information about a specific CDN network from the interconnection perspective. • CDN information contains basic data that is relevant to specific CDN. • CDN footprint defines a single footprint segment that is related to a specific CDN. • CDN capabilities describe the capabilities of a specific CDN within a specific footprint segment. D.1.1 CDN information data model Key Group Value type Comment id Basic string Id of CDN name Basic string Name of CDN icfInterface Basic url Address of Interface for Interconnection exchange. (SOAP, REST, etc.) rcfInterface Basic url Address of Interface for Interconnection exchange. (SOAP, REST, etc.) D.1.2 CDN footprint data model Key Group Value type Comment footprintID Basic integer Footprint identifier footprintTYPE Basic string Defines the footprint type (ip prefix, geolocation, BGP AS number) CDN-ID Basic integer CDN identifier footprintDATA Basic string The variable containing footprint data (as defined n footprintTYPE) D.1.3 CDN Capabilities data model Key Group Value type Comment footprintID Basic integer Footprint identifier httpFileTransfer Basic boolean Describes the network's capability of delivering files via http streaming Basic boolean Describes the network's capability of delivering streams isAuthorization Basic authentication Basic string Coma separated list of mechanisms dynamicStreaming Extented Set of (HLS, HDS, MSS, DASH) Defines supported dynamic streaming methods ETSI ETSI TS 182 032 V1.1.1 (2013-04) 47 D.2 Content related data models This clause describes the data models relevant to specific content items and their delivery: • Content related metadata data model includes all the basic information describing the content. • Content distribution reporting data model includes all the data related to the distribution status of a specific content. • Content request source data model includes all the data related to a source of content delivery request. • Content delivery reporting data model includes all the data related to delivery of a specific content. D.2.1 Content related metadata data model Key Group Value type Comment id Basic string Content identification name Basic string Content name contentProvider Basic string Content provider identification description Basic string Content description contentType Basic string Content MIME type transferType Basic file/stream Content transfer type isInfinite Basic boolean Identifies live streams length Basic long Number of bytes, content contains of metadataVersion Basic timestamp Time when metadata was updated from content provider fileVersion Basic timestamp Time when content was updated from content provider adaptation Extended boolean Defines if content adaptation is allowed qosDelivery Extended structure Defines the qos parameters for content D.2.2 Content distribution reporting data model Key Group Value type Comment content ID Basic string ID of content distributionPoint Basic string Name of distribution point status Basic no, download, ready, waiting for undeploy Content status hit ratio Basic double Content-specific hit ratio deploymentTime Extended long Number of seconds transfer has taken D.2.3 Content request source data model Key Group Value type Comment identity Basic string ID of user is optional isMobile Basic boolean Detect if device is moving (from GPS position, IP change, ip Basic string Client IPv4 address ipV6 Basic string Client IPv6 address location Basic GPS Client location downloaded Extended long Number of bytes transferred towards requester ETSI ETSI TS 182 032 V1.1.1 (2013-04) 48 D.2.4 Content delivery reporting data model Is list of one or more entities of following class. Key Group Value type Comment contentID Basic string ID of content requestorID Basic string Name of distribution point startTime Basic timestamp Timestamp of operation start endTime Basic timestamp Timestamp of operation stop status Basic Progress, success, fail, interrupted, paused Status of operation at the stop time D.3 Data model entity relations This clause visualizes the relations between various data model entities of CDN interconnection. Figure D.3.1: CDN-I data model entity relations ETSI ETSI TS 182 032 V1.1.1 (2013-04) 49 History Document history V1.1.1 April 2013 Publication
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1 Scope
The purpose of the present document is to define guidelines with regard to the interaction of non-call related H.248 procedures and generic network management use cases and vice versa. More specifically, the interaction between the following is considered: • Control procedures at the H.248 interface. These are the procedures between Media Gateway Controllers (primary and secondary) and their associated Media Gateways (primary, and secondary if available). These procedures primarily utilize the H.248 ServiceChange and H.248 Audit procedures. • Management procedures at the management interface(s) of H.248 systems (i.e. both Media Gateway Controller and Media Gateway) to perform non call related tasks such as configuration management (start-up, capability change, maintenance locking) and fault management (failure handling). It is intended that these guidelines are then subsequently used in corresponding H.248 profiles to produce detailed non-call related procedures. At the current time, the existing set of ETSI H.248 profiles ( [i.1], [i.2], [i.3] and [i.4]) lack any such detailed procedures. Specific management systems, architectures and protocols are outside the scope of the present document; only the general requirements and Use Cases related to the management system shall be discussed.
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1.1 Applicability
The present document is applicable to any network element that exhibits a H.248 interface and a management interface (e.g. SNMP). The intent of the present document is to provide guidelines so as to facilitate a consistent set of behaviour for non-call related procedures in the related H.248 profile specifications. Due to the general nature of the present document, it is possible that some of the procedures herein will not be applicable to certain H.248 profiles - it is for a specific profile itself to define which procedures are mandatory/optional/not applicable. The present document assumes an IP-based transport for H.248 signalling. The IP transport may be provided by either UDP or SCTP.
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1.2 Relation to H.248 Standards
The present document is considered to be complementary to H.248 standards where there are discrepancies between the present document and the correspondent ITU-T Recommendation H.248 series Recommendations, the procedures of these ITU-T Recommendations (in particular ITU-T Recommendation H.248.1 [i.5] and its annex F on ServiceChange), take precedence over those described in the present document. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 8
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2 References
References are either specific (identified by date of publication and/or edition number or version number) or non-specific. • For a specific reference, subsequent revisions do not apply. • Non-specific reference may be made only to a complete document or a part thereof and only in the following cases: - if it is accepted that it will be possible to use all future changes of the referenced document for the purposes of the referring document; - for informative references. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity.
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2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated references, only the edition cited applies. For non-specific references, the latest edition of the referenced document (including any amendments) applies. Not applicable.
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2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with regard to a particular subject area. For non-specific references, the latest version of the referenced document (including any amendments) applies. [i.1] ETSI ES 283 002 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); PSTN/ISDN Emulation Subsystem (PES); NGN Release 1 H.248 Profile for controlling Access and Residential Gateways". [i.2] ETSI ES 283 024 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); PSTN/ISDN Emulation: H.248 Profile for controlling Trunking Media Gateways in the PSTN/ISDN Emulation Subsystem (PES); Protocol specification". [i.3] ETSI ES 283 018 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Resource and Admission Control: H.248 Profile for controlling Border Gateway Functions (BGF) in the Resource and Admission Control Subsystem (RACS); Protocol specification". [i.4] ETSI ES 283 031 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IP Multimedia: H.248 Profile for controlling Multimedia Resource Function Processors (MRFP) in the IP Multimedia System (IMS); Protocol specification". [i.5] ITU-T Recommendation H.248.1 (2005): "Gateway Control Protocol: Version 3". [i.6] ITU-T Recommendation H.248.10 (2001): "Gateway control protocol: Media Gateway Resource Congestion Handling package". [i.7] ITU-T Recommendation H.248.14 (2002): "Gateway control protocol: Inactivity timer package". ETSI ETSI TS 183 025 V2.5.1 (2009-04) 9 [i.8] ITU-T Recommendation H.248.11 (2002): "Gateway control protocol: Media Gateway Overload Control package". [i.9] ETSI ES 283 039-4 (V2.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); NGN Overload Control Architecture; Part 4: Adaptative Control for the MGC". [i.10] ITU-T Recommendation H.248.40 (2007): "Gateway control protocol: Application Data Inactivity Detection package". [i.11] IETF RFC 4268: "Entity State MIB". [i.12] ITU-T Recommendation X.731: "Information technology - Open Systems Interconnection - Systems management: State management function". [i.13] ITU-T Recommendation H.248.8: " Gateway control protocol: Error code and service change reason description ".
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3 Definitions and abbreviations
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3.1 Definitions
For the purposes of the present document, the following terms and definitions apply: control association: H.248 Control Association is defined in clause F.2/H.248.1 version 3 [i.5] H.248 entity: any primary or secondary MGC or MG may be also denoted as H.248 entity NOTE 1: An H.248 entity relates to a Functional Entity (FE), any implementation of an H.248 entity is mapping the functional entity on a Physical Entity (PE). NOTE 2: E.g. a virtual MG (VMG) is a H.248 FE. Multiple VMGs are realized in a single physical MG, which relates to an H.248 PE. NOTE 3: Physical entities are sometimes also denoted as "platform" or "processor". primary Media Gateway (MG): no explicit definition in H.248 NOTE: The primary MG is rather implicitly defined. See mainly ITU-T Recommendation H.248.1 version 3 [i.5], clauses 7.2.8.1.11, 9, 11.2, 11.5, F.1, F.3.2, F3.5, F.3.11 or F.4.1.1. A primary MG is denoted by the facts that: 1) there is a single H.248 Control Association terminated in the MG; and that 2) there may be a secondary MG existing. The association between primary and secondary entity is given by support for redundancy on network level. primary Media Gateway Controller (MGC): according to "Primary MG" secondary Media Gateway (MG): according to "Primary MG" secondary Media Gateway Controller (MGC): according to "Primary MGC" NOTE: There can in general be a list of primary and secondary MGCs in each MG. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 10
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3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply: AGW Access GateWay DSP Digital Signal Processor FE Functional Entity IP Internet Protocol IS In Service MG Media Gateway MGC Media Gateway Controller MGW Media GateWay NGN Next Generation Network OOS Out-Of-Service PE Physical Entity RTP Real-time Transport Protocol SC ServiceChange (H.248) SCTP Stream Control Transmission Protocol SDO Standardization Development Organizations SNMP Simple Network Management Protocol TISPAN Telecommunications and Internet converged Services and Protocols for Advanced Networking TR Technical Report UDP User Datagram Protocol VMG Virtual Media Gateway
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4 Reference Architecture
Figure 1 illustrates the reference architecture assumed in the present document. MGC MG Management System H.248.1 Protocol Procedures Management Commands Management Commands Figure 1: Reference architecture The present document discusses the message primitives that may be passed over the Management Command interface and any related mappings into the H.248 control procedures and vice versa. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 11
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5 H.248 Concepts And Logical Entities
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5.1 H.248 Entities
H.248 commands and procedures are acting on H.248 logical entities. These are the different types: • Context: This is the entity that associates terminations together in a call or session. See also clause 6.1 of [i.5]. • NULL Context: This is a special Context which contains all Physical Terminations that are not associated with any other Termination. However, commands may still be initiated to and from these terminations. See also clause 6.1 of [i.5]. • Root Termination: This defines the MGW as an individual entity as a whole. See also clause 6.2.5 of [i.5]. • Physical Termination: This is an entity which has fixed physical characteristics (e.g. an analogue line) and requires pre-configuration via the management system prior to use within H.248 protocol. For such terminations, the MGC and MG are pre-provisioned to have a common view of the existing physical terminations. See also clause 6.2 of [i.5]. • Ephemeral Termination: This is a logical entity representing a dynamically created termination within the MGW (e.g. IP/RTP). No pre-configured characteristics are required for this type of entity, although in some profiles the MGC may have a dependency on the MG via the termination naming principles. See also clause 6.2 of [i.5]. Terminations may be individually addressed or as group (except Root Termination). Group addressing is performed via H.248 wildcarding.
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5.2 H.248 Non-Call Related Commands
The H.248.1 commands relevant to the present document are: • AuditValue: This command enables a MGC to request the supported packages and current state of properties, events, signals and statistics of terminations. For further details, see also clause 7.2.5 of [i.5]. • AuditCapability: This command enables a MGC to request all supported values for termination properties, events and signals allowed by the Media Gateway (i.e. the ROOT Termination). This command is not used in any of the TISPAN profiles and is thus considered to be out of scope in the present document. For further details, see also clause 7.2.6 of [i.5]. • ServiceChange: This command enables a MG to notify the MGC that a termination or group of terminations is about to be taken out of service or has just been returned to service. It also used by the MG to announce its availability to a MGC (registration), and to notify the MGC of impending or completed restart of the MG. The MGC may announce a handover to the MG by sending it a ServiceChange command. The MGC may also use ServiceChange to instruct the MG to take a termination or group of terminations in or out of service. For further details, see also clause 7.2.8 of [i.5]. • Notify: This command enables a MG to notify the MGC of any event occurring in the MG (that has been requested by the MGC). The Notify command is applicable to both call and non-call related procedures. Only the latter is in scope of the present document. For further details, see also clause 7.2.7 of [i.5]. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 12
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5.3 H.248 Service State
One of the key descriptors of Terminations in the present document is the ServiceStates property within the Termination State Descriptor: Possible values: InService The termination is in-service and functioning normally. OutOfService The termination is out-of-service and not available for traffic. Test The termination is undergoing testing. The MG/MGC may report changes to the service state via the Service Change Command to its peer. Changes to the service state can occur due to faults (MG only) or interaction with management commands (MG/MGC). In the latter case, the H248 Service State is assumed to reflect the overall/resulting availability status of the termination based on the administrative (i.e. the state of the resource as required by the management interface) and operational (i.e. the state of the resource based whether it is working correctly or not) states. Note that the transition into the TEST state has no impact on Service Change procedures. Service change procedures are impacted only in the transition from TEST to OUT OF SERVICE states (see table F2/H248.1 of [i.5]).
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6 Management Primitives
As stated previously, specific management systems, architectures and protocols are outside the scope of the present document. Rather, the present document considers only a high level set of primitives which directly result in the triggering of H.248 signalling. The following management primitives are defined in the present document: • Create Resource: This command creates a resource. A resource is typically created prior to it being enabled. This command has no impact on H.248 signalling and is included only for completeness. • Enable Resource: The resource moves from an OOS to an IS state (assuming that there is no problem with any related physical state) and is now available for traffic. • Disable Resource (Graceful): The resource is no longer available to new calls/connections. However, all existing calls are permitted to terminate naturally at which point the resource moves into the OOS state. If there are still remaining calls on the resource after a period of time, the operator may invoke the Disable Resource (Immediate) primitive. • Disable Resource (Immediate): Any existing calls/connections are force released, at which point the resource moves into the OOS state. • Delete Resource: This command deletes a resource. A resource would be disabled prior to it being deleted. This command has no impact on H.248 signalling and is included only for completeness. These management primitives (in general) are applicable at both the MG and MGC.
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7 Failure/Recovery Scenarios
Certain failure scenarios also result in the triggering of H.248 signalling. The present document defines the following set of such scenarios: • Nodal failure and recovery of a MG/MGC. This can be due to hardware or software faults. • Termination failure and recovery. Examples of this are termination failure/recovery on the MG (e.g. DSP failure, interface failure such as loss of synchronization on an E1, etc.). • User plane failure. Examples of this would be detection of loss of RTP media. The MG would inform the MGC of such failure and the MGC may force release the call. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 13 • MG-MGC signalling link (control association) failure/recovery. The detection of a signalling link failure results in H.248 signalling to restore the link. On restoring the link, the MG and MGC may have become out of step and thus additional H.248 audits are necessary to ensure the re-synchronization of each end.
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8 Redundancy Scenarios
The H.248 non call related procedures are also impacted by the redundancy architectures chosen at a MG/MGC. Examples of such scenarios are: • MGC Hand-Off. This functionality enables a MGC to terminate an existing control association and establish a new control association to an alternative MGC. This procedure can be applied to load share or due to maintenance action. • MGC Triggered MG Re-direct. This functionality enables a MGC to redirect an attempted registration to an alternative MGC. • MG Failover. This functionality enables a MG to inform a MGC that a secondary MG is taking over an existing control association. It should be noted that processor redundancy can be achieved within a functional node thus being invisible to the H.248 protocol peer or additionally within the functional node but between logical entities within that node and thus using H.248 procedures but using the same nodal address. The scope of the present document does not extend to inter-nodal protocol solutions to support other such redundancy scenarios.
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9 General Use Cases
The following use cases and their interaction with the H.248 non-call related procedures are considered in the present document. Configuration Management: • Enable MG. • Enable MGC. • Disable MG (Graceful). • Disable MG (Immediate). • Disable MGC. • Enable Termination. • Disable Termination (Graceful). • Disable Termination (Immediate). • Change of MG Resources. Fault Management - Failure and recovery: • MG failure and recovery. • MG termination failure and recovery. • MGC failure and recovery. • User plane failure. • MGC-MG signalling link failure and recovery. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 14 Performance Management: • MG Overload. • MGC Overload. Node Redundancy: • MGC Handoff. • MGC MG Triggered Redirect. • MG Failover. 10 Interaction Between Use Cases and Non-Call Related H.248 Procedures This clause contains high level functional descriptions of the non call-related H.248 procedures in relation to the Use Cases. There may be multiple procedures relating to one general use case. Clause 11 contains the detailed contents of each of the cited procedures. The procedure names are denoted by the use of UPPER CASE letters.
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10.1 Enable MG
This management primitive is applicable to both the MGC and MG. It is recommended that this primitive is initially sent to the MGC and subsequently to the MG.
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10.1.1 Enable MG (at MGC)
This use case is triggered by management action that results in a MG being enabled at the MGC. There are no H.248 procedures associated with this action. The MGC simply awaits a registration from the MG (see clause 10.1.2).
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10.1.2 Enable MG (at MG)
This use case is triggered by management action that results in a MG being brought into service. The MG will have been provisioned with the identity/address of one or more MGC(s). The H.248 procedures are dependent on whether the MG undergoes a cold or warm boot and are as follows: MG Cold Boot 1) The MG registers with one of its (pre-provisioned) MGCs using the MG REGISTRATION (COLD BOOT) procedure. This step enables the H.248 protocol version to be negotiated as well as the support of any H.248 profiles. 2) In the event of there being no response to the registration request, the MG follows the procedures of clause 11.5 of [i.5]. 3) On completion of the initial registration procedure, the MGC assumes that all physical terminations are in the NULL context and there are no existing ephemeral terminations. Thus no context/termination related audits are required to be performed. 4) The MGC may optionally perform a PACKAGES AUDIT procedure in order to determine the MG support of any optional packages in a mutually supported profile. 5) The MGC may optionally audit ROOT properties (in any mandatory and optional packages) via the AUDIT ROOT PROPERTIES procedure. 6) The MGC may optionally set properties and events (in any mandatory and optional packages) in the MG on ROOT level via the SET ROOT TERMINATION EVENTS/PROPERTIES procedure. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 15 7) The MG may optionally inform the MGC of the state of its physical terminations via a MG TERMINATION AVAILABLE/MG TERMINATION UNAVAILABLE procedure. 8) The MGC may optionally Audit the state of the physical terminations if it cannot be assumed that the state is in-service or out-of-service via the AUDIT TERMINATION STATE procedure. 9) The MGC should not deblock associated circuits toward peer nodes before it has determined the true service state of the MG's circuits by one of the two procedures above. MG Initial Registration Ack MG Initial Registration MGC MG Packages Audit Packages Audit Ack Set ROOT Term Events/Properties Set ROOT Term Events/Properties Ack (optional) (optional) MG Termination (Un)Available MG Termination (Un)Available Ack (optional) (optional) Audit Termination State Audit Termination State Ack (optional) Audit ROOT Properties Audit ROOT Properties Ack Figure 2: MG Cold Boot Procedures MG Warm Boot 1) The MG registers with one of its (pre-provisioned) MGCs using the MG RESTORATION procedure This step enables the H.248 protocol version to be negotiated as well as the support of any H.248 profiles. 2) In the event of there being no response to the registration request, the MG follows the procedures of clause 11.5 of [i.5]. 3) On completion of the re-registration procedure, the MGC does not assume that all physical terminations are in the NULL context and there may be existing ephemeral terminations. 4) The MGC may optionally perform a PACKAGES AUDIT procedure in order to determine the MG support of any optional packages in a mutually supported profile. This step is recommended if the related service change reason indicates that the capabilities/packages of the MG have changed. 5) The MGC may optionally audit ROOT properties (in any mandatory and optional packages) via the AUDIT ROOT PROPERTIES procedure. 6) The MGC may optionally set properties and events (in any mandatory and optional packages) in the MG on ROOT level via the SET ROOT TERMINATION EVENTS/PROPERTIES procedure. 7) The MGC may optionally perform a CONTEXT AUDIT procedure to determine/check the active contexts and connected terminations on the MG. 8) The MG may optionally inform the MGC of the state of its terminations via a MG TERMINATION AVAILABLE/MG TERMINATION UNAVAILABLE procedure. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 16 9) The MGC may optionally Audit the state of its terminations if it cannot be assumed that the state is in-service or out-of-service via the AUDIT TERMINATION STATE procedure. 10) The MGC should not deblock associated circuits toward peer nodes before it has determined the true service state of the MG's circuits by one of the two procedures above. MG Restoration Ack MG Restoration MGC MG Packages Audit Packages Audit Ack Set ROOT Term Events/Properties Set ROOT Term Events/Properties Ack (optional) (optional) MG Termination (Un)Available MG Termination (Un)Available Ack (if state changes have occurred) Audit Termination State Audit Termination State Ack Context Audit Context Audit Ack (optional) Audit ROOT Properties Ack Audit ROOT Properties (optional) (optional) Figure 3: MG Warm Boot Procedures
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10.2 Enable MGC
This management primitive is applicable only to the MGC and results in a MGC being brought into service. The MGC will optionally have been provisioned with the H.248 mid and possibly the transport address of the H.248 control association of its MGs. The following H.248 procedures are performed: 1) The MGC may optionally check on the availability of its MGs via the CHECK MG AVAILABILITY procedure. This is only possible if the MGC is aware of the pre-provisioned IP address of the MG and UDP transport is used. 2) If the MG is available, the MGC may optionally request the MG to register via the MGC INITIATED SERVICE RESTORATION procedure which causes the MG to initiate the MG RE-REGISTRATION (RESTART) procedure. 3) If the MG is available, the MGC may optionally audit ROOT properties in the MG via the AUDIT ROOT PROPERTIES procedure. 4) If an MG is available, the MGC may optionally set properties and events in the MG on ROOT level via the SET ROOT TERMINATION EVENTS/PROPERTIES procedure. 5) If an MG is available, the MGC may optionally perform a CONTEXT AUDIT procedure to determine the active contexts and connected terminations on the MG. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 17 6) If an MG is available, the MGC may optionally clean up hanging contexts/terminations via a WILDCARDED SUBTRACT. 7) If an MG is available, the MGC may optionally check on the service state of the physical terminations on the MG service via the AUDIT TERMINATION STATE procedure. 8) The MGC should not deblock associated circuits toward peer nodes before it has determined the true service state of the MG's circuits. Check MG Availability MGC MG Check MG Availability Ack Set ROOT Term Events/Properties Set ROOT Term Events/Properties Ack (optional) (optional) (optional) Audit Termination State Wildcarded Subtract Ack Context Audit Context Audit Ack (optional) MGC Initiated Service Restoration MGC Initiated Service Restoration Ack MG Ordered Re-Register MG Ordered Re-Register Ack (optional) (optional) Wildcarded Subtract Audit Termination State Ack (optional) Audit ROOT Properties Audit ROOT Properties Ack (optional) Figure 4: Enable MGC Procedures
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10.3 Disable MG (Graceful)
This primitive is applicable to both the MG and MGC and covers the use case of management action that results in a MG being taken out of service gracefully. It is recommended that the network management system performs a Disable MG (Graceful) command to the MGC. The one scenario where a Disable MG (Graceful) command to the MG makes sense is for an Access Gateway in order to inhibit new calls being initiated toward the MGC during the graceful period, and even in this case a MGC would be able to reject any originating calls appropriately. In addition, the management primitive typically has no equivalent of the H.248 ServiceChangeDelay - rather the acceptable period during which all affected calls/connections ought to be removed is determined by the operator. Therefore when mapping into H.248, a default value for the ServiceChangeDelay period would need to be applied.
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10.3.1 Disable MG (Graceful) (at MGC)
On receipt of this primitive, the MGC performs the following actions: 1) The MGC inhibits any new calls/connections to the MG and allows existing calls/connections to expire naturally/normally. 2) In the event of new calls originating from the MG (e.g. an AGW), the MGC would handle them appropriately via call related procedures (e.g. reject the call attempt and connect a failure indication). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 18 3) When all calls have been released, the management system is informed. Optionally, the MGC may also place the MG out of service via the MGC INITIATED SERVICE CANCELLATION procedure. MGC MG (optional) MGC INITIATED SERVICE CANCELLATION I di t A k MGC INITIATED SERVICE CANCELLATION ACK I di t A k Figure 5: MGC INITIATED SERVICE CANCELLATION Procedure
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10.3.2 Disable MG (Graceful) (at MG)
The following H.248 procedures are applied: 1) The MG informs the MGC via the MG SERVICE CANCELLATION (GRACEFUL) procedure. This procedure enables the MG to specify a timer (the ServiceChangeDelay) during which it is anticipated that all existing calls/connections on that MG will expire normally. 2) If applicable, the MG may prevent new originating calls being offered to the MGC. 3) The MGC inhibits any new calls/connections to the MG and allows existing calls/connections to expire naturally/normally. 4) At the end of the ServiceChangeDelay period, any remaining connections are left hanging on the MG. 5) At the end of the ServiceChangeDelay period, the MGC force releases any remaining calls that have not expired naturally (but does not signal to the MG since the control association is now assumed to be down). MG Service Cancellation (Graceful) MGC MG MG Service Cancellation (Graceful) Ack (expiry of graceful timer) Figure 6: MG SERVICE CANCELLATION (GRACEFUL) Procedure
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10.4 Disable MG (Immediate)
This primitive is applicable to both the MG and MGC and covers the use case of management action that results in a MG being taken out of service immediately.
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10.4.1 Disable MG (Immediate) (at MGC)
On receipt of this primitive, the MGC performs the following actions: 1) The MGC inhibits any new calls/connections to the MG and force releases existing calls/connections. 2) In the event of new calls originating from the MG (e.g. an AGW), the MGC would handle them appropriately via call related procedures (e.g. reject the call attempt and connect a failure indication). 3) When all calls have been released, the management system is informed. Optionally, the MGC may also place the MG out of service via the MGC INITIATED SERVICE CANCELLATION procedure (see figure 5). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 19
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10.4.2 Disable MG (Immediate) (at MG)
The following H.248 procedures are performed: 1) The MG informs the MGC via the MG SERVICE CANCELLATION (IMMEDIATE) procedure. 2) The MG responds to the management system. Note that existing connections are still hanging on the MG. 3) On receipt of the MG SERVICE CANCELLATION (IMMEDIATE) message, the MGC force releases any calls/connections associated with that MG. However, the connections cannot be removed on the MG due to the control association being down. Since connections may be left hanging, it is recommended that the DISABLE MG (Immediate) primitive is applied firstly at the MGC and then at the MG. MGC MG MG Service Cancellation ( Immediate) MG Service Cancellation (Immediate) Ack Figure 7: MG SERVICE CANCELLATION (Immediate) Procedure
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10.5 Disable MGC
This primitive is sent to a MGC and results in a MGC being taken out of service. Prior to the MGC being disabled, it is recommended that the MGC inform its dependent MGs to move their control associations to an alternative MGC via the MGC HANDOFF procedure (clause 10.18) or that all dependent MGs are disabled prior to disabling the MGC (clause 10.4).
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10.6 Enable Termination
This management primitive is applicable to both the MGC and MG. It is recommended that this primitive is initially sent to the MGC and subsequently to the MG.
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10.6.1 Enable Termination (at MGC)
The following H.248 procedures are performed: 1) The MGC may: a) Optionally assume that the corresponding termination is in-service on the MG, in which case the MGC attempts to use the termination and will receive an error code if the termination is not available at the MG end. On receipt of any such error code, the MGC desists from using the termination until such time as the procedures in clause 10.6.2 are completed. b) Optionally assume that the corresponding termination is out of service and await the completion of the procedures in clause 10.6.2. c) Optionally audit the service state of the termination via the AUDIT TERMINATION STATE procedure. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 20 MGC MG Audit Termination State Audit Termination State Ack Figure 8: Audit Termination State Procedure
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10.6.2 Enable Termination (at MG)
The following H.248 procedures are performed: 1) The MG informs the MGC via the MG TERMINATION AVAILABLE procedure. If a successful response is obtained the termination is now in-service at both the MG and MGC. If a negative response/error descriptor with error code #511 "Temporarily Busy" (defined in ITU-T Recommendation H.248.8 [i.13]) indicating a temporary busy condition in the MGC is received, the MG periodically repeats the MG TERMINATION AVAILABLE procedure until a successful response is received. If multiple repetitions are needed, the repetition rate shall be continuously decreased over time. The minimum inter-transmit time under such conditions shall be 100 ms. NOTE: In case the MG termination procedure is to be repeated and if the corresponding MG termination has undergone a Service State change in the meantime, only the latest Service State is reported. This may imply a change of the procedure to be applied (e.g. MG TERMINATION UNAVAILABLE). MGC MG MG Termination Available MG termination Available Ack Figure 9: MG Termination Available Procedure
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10.7 Disable Termination (Graceful)
This primitive is applicable to both the MG and MGC and covers the use case of management action that results in a termination being taken out of service gracefully. It is recommended that the network management system performs a Disable Termination (Graceful) command to the MGC. The one scenario where a Disable Termination (Graceful) command to the MG makes sense is for an Access Gateway in order to inhibit new calls being initiated toward the MGC during the graceful period - and even in this case a MGC would be able to reject any originating calls appropriately.
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10.7.1 Disable Termination (Graceful) (at MGC)
The following actions are performed: 1) The MGC prevents any new calls/connections being offered to the affected termination. 2) If there are any current calls/connections on the termination, the MGC allows them to expire normally/naturally. 3) When all calls are released, the MGC informs the management system. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 21
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10.7.2 Disable Termination (Graceful) (at MG)
The following actions are performed: 1) The MG informs the MGC via the MG TERMINATION OOS GRACEFUL procedure. This procedure enables the MG to specify a timer (the ServiceChangeDelay) during which it is anticipated that all existing calls/connections on that MG termination will expire normally. On receipt of this message, the MGC now inhibits any new calls/connections to the specified MG termination and allows existing calls/connections to expire naturally/normally. NOTE 1: The use of delay means that the network management has lost control of when the calls will be forced- released, in many cases the operator would control this and depending on number of calls still active may chose to defer the maintenance action. 2) If a successful response is obtained at the end of the ServiceChangeDelay period, the MG places the termination in the out of service state. If a negative response/error descriptor with error code #511 "Temporarily Busy" (defined in ITU-T Recommendation H.248.8 [i.13]) indicating a temporary busy condition in the MGC is received, the MG periodically repeats the MG TERMINATION OOS GRACEFUL procedure until a successful response is received. Furthermore the MG may adapt the ServiceChangeDelay timer accordingly. If multiple repetitions are needed, the repetition rate shall be continuously decreased over time. The minimum inter-transmit time under such conditions shall be 100 ms. NOTE 2: In case the MG termination procedure is to be repeated and if the corresponding MG termination has undergone a Service State change in the meantime, only the latest Service State is reported. This may imply a change of the procedure to be applied (e.g. MG TERMINATION AVAILABLE). 3) Additionally, at the end of the ServiceChangeDelay period, the MGC force releases any remaining calls that have not expired naturally and subtracts the terminations on the MG since the control association is still up. MG Termination OOS Graceful MGC MG MG Termination OOS Graceful Ack (expiry of graceful timer) Figure 10: MG Termination OOS Graceful Procedure
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10.8 Disable Termination (Immediate)
This primitive is applicable to both the MG and MGC and covers the use case of management action that results in a termination being taken out of service immediately.
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10.8.1 Disable Termination (Immediate) (at MGC)
The following H.248 procedures are performed: 1) The MGC force releases all affected calls/connections, subtracting appropriate terminations on the MG. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 22
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10.8.2 Disable Termination (Immediate) (at MG)
This use case is triggered by management action that results in a MG termination being taken out of service immediately. The following H.248 procedures are performed: 1) The MG informs the MGC via the MG TERMINATION UNAVAILABLE procedure. If a successful response is obtained the termination is now out-of-service at both the MG and MGC. If a negative response/error descriptor with error code #511 "Temporarily Busy" (defined in ITU-T Recommendation H.248.8 [i.13]) indicating a temporary busy condition in the MGC is received, the MG periodically repeats the MG TERMINATION UNAVAILABLE procedure until a successful response is received. If multiple repetitions are needed, the repetition rate shall be continuously decreased over time. The minimum inter-transmit time under such conditions shall be 100 ms. NOTE: In case the MG termination procedure is to be repeated and if the corresponding MG termination has undergone a Service State change in the meantime, only the latest Service State is reported. This may imply a change of the procedure to be applied (e.g. MG TERMINATION AVAILABLE). 2) The MGC now force releases all affected calls/connections including subtracting appropriate terminations on the MG. MGC MG MG Termination Unavailable MG Termination Unavailable Ack Figure 11: MG Termination Unavailable Procedure
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10.9 MG Failure and Recovery
This use case is triggered by a hardware/software failure on the MG. The following H.248 procedures are performed: 1) If possible, the MG informs the MGC via the MG SERVICE CANCELLATION (IMMEDIATE) procedure. The MGC force releases all affected calls. 2) On recovering, the MG restarts and informs the MGC. The procedures of clause 10.1.2 are applicable. MG Service Cancellation ( Immediate) MGC MG MG Service Cancellation (Immediate) Ack (MG recovery) See 10.1.2 Figure 12: MG Failure and Recovery Procedures ETSI ETSI TS 183 025 V2.5.1 (2009-04) 23 10.10 MG Termination Failure and Recovery This use case is triggered by a hardware/software failure on the MG termination (e.g. loss of synchronization on an E1). The following H.248 procedures are performed: 1) The MG informs the MGC via the MG TERMINATION UNAVAILABLE procedure. The MGC force releases any affected calls (and subtracts related terminations on the MG). 2) On the fault being cleared, the MG informs the MGC via the MG TERMINATION AVAILABLE procedure. MG Termination Unavailable MGC MG MG Termination Unavailable Ack (recovery of termination) MG Termination Available MG Termination Available Ack Figure 13: MG Termination Failure and Recovery Procedures 10.11 MGC Failure and Recovery This use case is triggered by a hardware/software failure on the MGC. The following H.248 procedures are performed: 1) During the outage, the procedures associated with the MG detecting the loss of the control association are applicable (see clause 10.13). 2) When the MGC recovers, the procedures of clause 10.2 are applicable. 10.12 User Plane Failure 10.12.1 Failure affecting a Single Termination This use case is triggered by the MG detecting loss of application data (e.g. RTP) on an ephemeral termination. The following H.248 procedures are performed: 1) During the establishment of the connection, the MGC is assumed to have armed the MG to report an appropriate ObservedEvent which would be associated with user plane failure. There are a number of events that could be used for this purpose (e.g. nt/netfail, nt/qalert (see clause E.11 of [i.5]), g/cause (see clause E.1 of [i.5], adid/ipstop (see [i.10]) etc.). 2) The MG detects loss of user plane data on one or more streams and notifies the MGC via the USER PLANE FAILURE procedure. The MG should avoid sending an avalanche of notifications where loss of user plane data is detected simultaneously across multiple ephemeral terminations. 3) On being informed of user plane failure, the MGC would typically remove the affected stream(s) and/or force release the affected call and subtract the related terminations. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 24 MGC MG User Plane Failure User Plane Failure Ack Figure 14: MG User Plane Failure Procedure 10.12.2 Failure affecting Multiple Terminations The events of previous clause may be applied as in this scenario as well. The major difference is the fact, that in this scenario the failure affects multiple ephemeral terminations in parallel. This may lead to a burst arrival of correspondent event notifications at the MGC. Alternative failure reporting could be based on the use of ServiceChange with appropriate wildcarding. 10.13 MGC-MG Control Association Failure and Recovery The general framework for "MGC-MG control association monitoring" is defined in clause 11.6 of [i.5]. If UDP transport is used to convey the H.248 signalling, then the control association is indirectly monitored via the Inactivity Package (see [i.7]). In this case, it is assumed that the MGC has previously initiated the inactivity timer on the MG via the SET ROOT TERMINATION EVENTS/PROPERTIES procedure (see clause 10.1). This approach is based on the MGC being polled by the MG. An unsuccessful event notification can be the result of either a failure in the MGC entity, or a failure of the IP transport. If SCTP transport is used, then the SCTP association is monitored via SCTP procedures (which are out of scope of the present document) and the H.248 application layer is informed by the SCTP layer when the SCTP association goes down/comes up. The following H.248 procedures are performed: 1) For UDP transport, the MGC should endeavour to send at least one message to the MG during the period of the inactivity timer. If there are no call related messages, the MGC may use the CHECK MG AVAILABILITY procedure. If this procedure fails, the MGC periodically re-attempts the procedure to check if the control association is once more OK. 2) For UDP transport, on expiry of the inactivity timer, if the MG has received a message (including an acknowledgment) from the MGC during the inactivity timer period, then the MG resets the inactivity timer. 3) For UDP transport, on expiry of the inactivity timer, if the MG has not received a message (including an acknowledgment) from the MGC during the inactivity timer period, then the MG initiates the ROOT EVENT NOTIFICATION procedure to notify the MGC of the expired inactivity timer. 4) For UDP transport, if the ROOT EVENT NOTIFICATION procedure is successfully acknowledged, then the MG resets the inactivity timer. 5) For UDP transport, if no acknowledgement is received, then the control association is deemed to be down after normal H.248 retransmissions have occurred. 6) For UDP transport, the MG now attempts to re-establish the lost control association via the MG LOST COMMUNICATION (DISCONNECTED) procedure. If no acknowledgement is received (and H.248 retransmissions have occurred), then the MG attempts to establish an alternative control association via the MG LOST COMMUNICATION (FAILOVER) procedure. 7) For SCTP transport, on being informed by the SCTP layer that the SCTP association is now up, the MG re-establishes the H.248 control association via the MG LOST COMMUNICATION (DISCONNECTED) or MG LOST COMMUNICATION (FAILOVER) procedure (dependent on whether the new SCTP association is to the same MGC or different MGC as previously). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 25 8) When the control association is re-established, the MGC may optionally re-synchronize its data with the MG via the AUDIT ROOT PROPERTIES, CONTEXT AUDIT and AUDIT TERMINATION STATE procedures. 9) When the control association is re-established, the MG informs the MGC of the state of its terminations via the MG TERMINATION AVAILABLE/MG TERMINTION UNAVAILABLE procedure if any changes occurred which it was unable to report during the signalling link outage. 10) When the control association is re-established, commands that were buffered during the outage period may be sent. | Check MG Availability Ack Check MG Availability MGC1 MG ROOT Event Notification (inactivity timer) MG Lost Communication (Disconnected) ROOT Event Notification (inactivity timer) UDP transport (inactivity timer running) (timer expiry & reset) | (timer expiry) MG Lost Communication (Failover) Context Audit Context Audit Ack (start inactivity timer) Optional Audit Termination State Audit Termination State Ack If state changes occurred during outage MG Termination (Un)Available MG termination (Un)Available Ack Optional MG Lost Communication (Disconnected) | | MG Lost Communication (Failover) Ack A k MGC2 Audit ROOT Properties Audit ROOT Properties Ack Optional Figure 15: Control Association Failure and Recovery Procedures (UDP) ETSI ETSI TS 183 025 V2.5.1 (2009-04) 26 WC – I’ve ad | MGC MG MG Lost Communication (Disconnected / Failover ) MG Lost Communication (Disconnected / Failover) Ack A k STCP Transport (SCTP association failure) | (SCTP association OK) Context Audit Context Audit Ack Optional Audit Termination State Audit Termination State Ack Optional MG Termination (Un)Available MG termination (Un)Available Ack If state changes occurred during outage Optional Audit ROOT Properties Audit ROOT Properties Ack Figure 16: Control Association Failure and Recovery Procedures (SCTP) 10.14 MG Overload This use case is triggered by the MG entering an overloaded state. It is assumed that that MGC has previously armed the MG for notification of overload via the SET ROOT TERMINATION EVENTS/PROPERTIES procedure. Examples of packages for such notification would be the MG Overload Control Package (see [i.8]) or the MG Resource Handling Package (see [i.6]). The following H.248 procedures are performed: 1) The MG is then pushed into an overload state by excessive call related activity. 2) The MG informs the MGC of its overload condition via the ROOT EVENT NOTIFICATION procedure. If this notification is based on [i.8], then such a notification is triggered by the receipt of a new ADD request on the MG - else the notification may be sent autonomously. 3) On receipt of this notification, the MGC takes appropriate action to reduce the load offered to the MG. MGC MG ROOT Event Notification (MG overload) ROOT Event Notification Ack Figure 17: MG Overload Notification Procedure ETSI ETSI TS 183 025 V2.5.1 (2009-04) 27 10.15 MGC Overload This procedure is applicable only where the MGC is controlling MGs that are capable of generating traffic (e.g. an AGW). The following H.248 procedures are performed: 1) The MGC is pushed into an overload state by excessive call related activity. 2) The MGC informs its dependent MGs of its overload condition via the MGC OVERLOAD NOTIFICATION procedure. A suitable package for this notification would be [i.9]. 3) On receipt of this notification, the MG takes appropriate action to reduce the load offered to the MGC (see [i.9]). MGC MG MGC Overload Notification MGC Overload Notification Ack Figure 18: MGC Overload Procedure 10.16 MGC Hand-Off This use case is triggered by management action that results in the MGC moving an existing control association to an alternative MGC address (e.g. when a single-homed IP host MGC entity provides multiple IP ports for the IP transport connection; or when the MGC entity is realized as multi-homed IP host, i.e. provides multiple IP interfaces. The former "hand-off to an alternative address" relates then to an IP port redirection, the later to an IP interface redirection). This could be done as a load balancing exercise or as a pre-condition to taking a MGC out of service. The following H.248 procedures are performed: 1) The MGC requests its MGs to move an existing control association to a specified alternative MGC address via the MGC HANDOFF procedure. On receipt of this message, the MG then forms a new control association to the specified alternate MGC address via the MG RE-REGISTRATION (HANDOFF) procedure. MGC Hand-Off MGC (initial address) MG MGC Hand-Off Ack MG Re-Registration (Handoff) MG Re-Registration (Handoff) Ack MGC (alternative address) Figure 19: Hand-Off Procedures ETSI ETSI TS 183 025 V2.5.1 (2009-04) 28 10.17 MGC Triggered MG Redirect This use case is triggered by an MGC rejecting a registration request from an MG and providing an alternative MGC address in the response. This relates to a redirection of the IP port or the entire IP interface (see clause 10.16). This could be done as a load balancing exercise. The following H.248 procedures are performed: 1) The MGC on receipt of a registration request, provides an alternative MGC identity/address in the registration response. This is shown in the MG REGISTRATION REDIRECT procedure. The MG subsequently repeats the original registration request to the alternate MGC. MGC MG MG Registration MG Registration (Redirect) Ack Figure 20: MG Registration Redirect Procedure 10.18 MG Failover This use case is triggered by management action that results in the MG swapping over from a primary/worker MG to a secondary/standby MG. This swap over can either be initiated by the Primary MG or the Secondary MG. The following H.248 procedures are performed: Primary MG Initiated 1) The Primary MG is about to go out of service and wishes to relinquish processing to a Secondary MG. The Primary MG firstly informs the MGC that it is about to go out of service via the MG REDUNDANT TAKEOVER (PRIMARY) procedure. On completion of this procedure, the control association to the MGC is terminated. 2) The Secondary MG then registers with the MGC using the procedures in clause 10.1.2 (Warm Boot). MGC MG (secondary) MG Redundant Takeover (Primary) MG Redundant Takeover (Primary) Ack MG (primary) Warm Boot procedures Figure 21: MG REDUNDANT TAKEOVER (PRIMARY) Procedure Secondary MG Initiated 1) In this case, the Secondary MG initiates the swap over (e.g. by detecting the failure of the Primary MG) via the MG REDUNDANT TAKEOVER (SECONDARY) procedure. 2) On completion of this procedure, the control association is now established between the MGC and Secondary MG. The procedures in clause 10.1.2 (Cold/Warm Boot) from bullet 3 onwards are then are then applicable. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 29 MGC MG (secondary) W MG Redundant Takeover (Secondary) MG Redundant Takeover (Secondary) Ack Figure 22: MG REDUNDANT TAKEOVER (SECONDARY) Procedure 10.19 Change of MG Resources This use case is triggered by management action that results in a change to MG resources on an In-Service MG such that the applied change does not result in a Service Change message, but does require the MGC to be notified of the applied change via a H248 NOTIFY message. The MGC has previously armed the necessary event via the SET ROOT EVENTS/PROPERTIES procedure (see clause 10.1). 1) The MG's resources are changed via Management Configuration and the MG has been previously armed to inform the MGC of the related change. 2) The MG informs the MGC of the change in its resources via the ROOT EVENT NOTIFICATION procedure. ROOT Event Notification MGC MG W ROOT Event Notification Ack Figure 23: Change to MG Resources Procedure ETSI ETSI TS 183 025 V2.5.1 (2009-04) 30 11 Non-Call Related H.248 Procedures and their Contents Table 1 lists the procedures described in this clause. Table 1 Procedure Clause MG REGISTRATION (COLD BOOT) (see note) 11.1 MG Restoration (see note) 11.2 Packages Audit 11.3 Context Audit 11.4 MG Termination Available 11.5 MG Termination Unavailable 11.6 Audit Termination State 11.7 Set ROOT Termination Events/Properties 11.8 MGC INITIATED SERVICE RESTORATION 11.9 Check MG Availability 11.10 MG SERVICE CANCELLATION (GRACEFUL) 11.11 MG SERVICE CANCELLATION (IMMEDIATE) 11.12 MGC Hand-Off 11.13 MG RE-REGISTRATION (HANDOFF) (see note) 11.14 MG Termination OOS Graceful 11.15 MGC Overload Notification 11.16 MG Registration Redirect (see note) 11.17 User Plane Failure 11.18 ROOT EVENT NOTIFICATION 11.19 MG LOST COMMUNICATION (DISCONNECTED) 11.20 MG LOST COMMUNICATION (FAILOVER) 11.21 MG REDUNDANT TAKEOVER (PRIMARY) 11.22 MG RE-REGISTRATION (RESTART) 11.23 Wildcarded Subtract 11.24 MG REDUNDANT TAKEOVER (SECONDARY) 11.25 MGC INITIATED SERVICE CANCELLATION 11.26 Void 11.27 Audit ROOT Properties 11.28 NOTE: These procedures are initiated using H.248 version 1 and may be used to negotiate a higher protocol version. All other procedures are initiated using the negotiated protocol version. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 31
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11.1 MG Registration (Cold Boot)
Table 2 shows the contents of the MG REGISTRATION (COLD BOOT) and MG REGISTRATION (COLD BOOT) Ack command/response pair. Table 2: MG Registration (Cold Boot) and MG Registration (Cold Boot) Ack Command/Response Initiated Information element name Information element required Information element description MG Registration (Cold Boot) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to RESTART. Reason M This information element indicates the reason for the command. This is set to 901 - "Cold Boot". Service Change Profile O Indicates the name of a supported H.248 profile. Protocol Version O Indicates the highest H.248 version supported by the MG - if other than 1. MG Registration (Cold Boot) Ack MGC Context M As received. Command M As received. Termination M As received. Protocol Version O If the highest protocol version supported by the MGC is lower than that proposed by the MG, this parameter must be included. If the highest protocol version supported by the MGC is equal to that proposed by the MG, this parameter may be included. Note that if the protocol version supported by the MGC is greater than that proposed by the MG, the command is rejected with an error response 406 ("Version Not Supported"). Service Change Profile O This information element indicates the profile (name and version) supported by the MGC if different from that proposed by the MG. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 32
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11.2 MG Restoration
Table 3 shows the contents of the MG Restoration and MG Restoration Ack command/response pair. Table 3: MG Restoration and MG Restoration Ack Command/Response Initiated Information element name Information element required Information element description MG Restoration MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to RESTART. Reason M This information element indicates the reason for service change. This is set to 900 ("Service Restored") or 902 ("Warm Boot") or 916 ("Packages Change" ) or 917 ("Capabilities Change") or 918 "Cancel Graceful"). Service Change Profile O Indicates the name of a supported H.248 profile. Protocol Version O Indicates the highest H.248 version supported by the MG - if other than 1. MG Restoration Ack MGC Context M As received. Command M As received. Termination M As received. Protocol Version O If the highest protocol version supported by the MGC is lower than that proposed by the MG, this parameter must be included. If the highest protocol version supported by the MGC is equal to that proposed by the MG, this parameter may be included. Note that if the protocol version supported by the MGC is greater than that proposed by the MG, the command is rejected with an error response 406 ("Version Not Supported"). Service Change Profile O This information element indicates the profile (name and version) supported by the MGC if different from that proposed by the MG.
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11.3 Packages Audit
This procedure is typically performed against the ROOT termination, in which case the MG returns all supported packages. It is also possible for the MGC to request a packages audit against other than the ROOT termination (e.g. a circuit termination) in which case the MG returns the sub-set of the packages that are applicable to the termination type. However, it is recommended that a packages audit be performed on the ROOT termination since the MGC can be expected to know how the returned set of packages ought to be used in relation to its different termination types. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 33 Table 4 shows the contents of the Packages Audit and Packages Audit Ack command/response pair. Table 4: Packages Audit and Packages Audit Ack Command/Response Initiated Information element name Information element required Information element description Packages Audit MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Audit packages M This is the Audit Descriptor requesting "Packages". Packages Audit Ack MG Context M As received. Command M As received Termination M As received. Package List M The list of supported packages.
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11.4 Context Audit
This procedure is invoked by the MGC to check/determine the list of active contexts and related terminations on the MG. There are a number of variations to this audit dependent on the amount of information available to the MGC prior to the audit (e.g. context identity known or termination naming scheme known etc.). A MGC may choose to use one or a combination of these variations dependent on its specific audit requirements. Tables 5 to 8 shows the contents of the various Context Audit and Context Audit Ack command/response pair. Table 5: Context Audit and Context Audit Ack (termination id known) Command/Response Initiated Information element name Information element required Information element description Context Audit MGC Context M This information element indicates the H.248 context for the command. Set to ALL or NULL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to a specific termination identity known by the MGC (e.g. aln/4). Audit Information O This is the Audit Descriptor requesting the appropriate information to be returned (e.g. "Media"). Context Audit Ack (see note) MG Context M The specific context with which the termination is currently associated. Command M As received. Termination M As received. Audited Information O The information requested. NOTE: In the event of a termination/context mismatch, then an error 435 would be returned. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 34 Table 6: Context Audit and Context Audit Ack (context known) Command/Response Initiated Information element name Information element required Information element description Context Audit MGC Context M This information element indicates the H.248 context for the command. Set to a specific (non NULL) value. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to a specific termination identity or a wildcarded to ALL. Audit Information O This is the Audit Descriptor requesting the appropriate information to be returned (e.g. "Media"). Context Audit Ack MG Context M As received (see note). Command M As received. Termination(s) M As received (if a specific termination in the request), else a list of termination identities (if wildcarded in the request). Audited Information O The information requested (per termination). NOTE: In the event of the context not being known at the MG, an error 435 would be returned. Table 7: Context Audit and Context Audit Ack (termination id partly known) Command/Response Initiated Information element name Information element required Information element description Context Audit MGC Context M This information element indicates the H.248 context for the command. Set to ALL or NULL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to a partially wildcarded termination, e.g. ephemeral/5/*. Audit Information O This is the Audit Descriptor requesting the appropriate information to be returned. Context Audit Ack MG Context M One or more active contexts associated with the wildcarded termination identity (see note). Command M As received. Termination(s) M For each returned context, one or more matching terminations. Audited Information O The information requested. (per termination). NOTE: In the event of there a mismatch between the wildcarded termination and specified context, an error 431 would be returned. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 35 Table 8: Context Audit and Context Audit Ack (context list) Command/Response Initiated Information element name Information element required Information element description Context Audit MGC Context M This information element indicates the H.248 context for the command. Set to ALL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Context Audit Ack MG Context M One or more active contexts present on the MG. Command M Set to AUDIT VALUE. Termination(s) M For each returned context, the ROOT termination is returned. NOTE: In the event of there being a mismatch between the wildcarded termination and specified context, an error 431 would be returned.
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11.5 MG Termination Available
Table 9 shows the contents of the MG Termination Available and MG Termination Available Ack command/response pair. Table 9: MG Termination Available and MG Termination Available Ack Command/Response Initiated Information element name Information element required Information element description MG Termination Available MG Context M This information element indicates the H.248 context for the command. Set to NULL or specific. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to a specific termination identity or a partially wildcarded identity (e.g. an E1). Method M This information element indicates the method for the command. This is set to RESTART. Reason M This information element indicates the reason for the command. This is set to 900 - "Service Restored". MG Termination Available Ack MGC Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 36
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11.6 MG Termination Unavailable
Table 10 shows the contents of the MG Termination Unavailable and MG Termination Unavailable Ack command/response pair. Table 10: MG Termination Unavailable and MG Termination Unavailable Ack Command/Response Initiated Information element name Information element required Information element description MG Termination Unavailable MG Context M This information element indicates the H.248 context for the command. Set to NULL, ALL or specific. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to a specific termination identity or a partially wildcarded identity (e.g. an E1). Method M This information element indicates the method for the command. This is set to FORCED. Reason M This information element indicates the reason for the command. This is set to 904 ("Termination Malfunction") or 905 ("Termination Taken OOS") or 906 ("Loss of Lower Layer Connectivity"), or 907 ("Transmission Failure") or 910 ("Media Capability Failure") or 912 ("Mux Capability Failure") or 913 ("Signal Capability Failure") or 914 ("Event Capability Failure" or 915 ("State Loss"). MG Termination Unavailable Ack MGC Context M As received. Command M As received Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 37
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11.7 Audit Termination State
Table 11 shows the contents of Audit Termination State and Audit Termination State Ack command/response pair. Table 11: Audit Termination State and Audit Termination State Ack Command/Response Initiated Information element name Information element required Information element description Audit Termination State MGC Context M This information element indicates the H.248 context for the command. Set to ALL or specific or NULL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to a specific termination identity or a partially wildcarded identity (e.g. an E1). Audit Service State M This is the Audit Descriptor requesting the Service State in the Termination State Descriptor. Audit Termination State Ack MG Context M The specific/NULL context with which the termination is currently associated (see note). Command M As received Termination M As received. Service State M The Service State in the Termination State Descriptor. NOTE: If the termination does not match the specified context, then a 430 (wildcarded termination) or 435 (specific termination) error is returned.
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11.8 Set ROOT Termination Events/Properties
Table 12 shows the contents of Set ROOT Termination Events/Properties and Set ROOT Termination Events/Properties Ack command/response pair. Table 12: Set ROOT Termination Events/Properties and Set ROOT Termination Events/Properties Ack Command/Response Initiated Information element name Information element required Information element description Set ROOT Termination Events/Properties MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to MODIFY. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. ROOT Properties O These are the ROOT level properties - e.g. "Normal MGC Execution Time". ROOT Events O These are the ROOT level events - e.g. notification of expiry of inactivity timer, notification of overload etc. Set ROOT Termination Events/Properties Ack MG Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 38
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11.9 MGC Initiated Service Restoration
Table 13 shows the contents of the MGC Initiated Service Restoration and MGC Initiated Service Restoration Ack command/response pair. Table 13: MGC Initiated Service Restoration and MGC Initiated Service Restoration Ack Command/Response Initiated Information element name Information element required Information element description MGC Initiated Service Restoration MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to RESTART. Reason M This information element indicates the reason for the command. This is set to 900 ("Service Restored") or 901 ("Cold Boot"). MGC Initiated Service Restoration Ack MG Context M As received. Command M As received. Termination M As received. 11.10 Check MG Availability Table 14 shows the contents of the Check MG Availability and Check MG Availability Ack command/response pair. Table 14: Check MG Availability and Check MG Availability Ack Command/Response Initiated Information element name Information element required Information element description Check MG Availability MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Check MG Availability Ack MG Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 39 11.11 MG Service Cancellation (Graceful) Table 15 shows the contents of the MG Initial OOS Graceful and MG Service Cancellation (Graceful) Ack command/response pair. Table 15: MG Service Cancellation (Graceful) and MG Service Cancellation (Graceful) Ack Command/Response Initiated Information element name Information element required Information element description MG Service Cancellation (Graceful) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to GRACEFUL. Reason M This information element indicates the reason for the command. This is set to 908 - "MG Impending Failure" or 905 - "Termination OOS". Service Change Delay O Indicates the period before which the MG will go out of service. MG Service Cancellation (Graceful) Ack MGC Context M As received. Command M As received. Termination M As received. 11.12 MG Service Cancellation (Immediate) Table 16 shows the contents of the MG Service Cancellation (Immediate) and MG Service Cancellation (immediate) Ack command/response pair. Table 16: MG Service Cancellation (Immediate) and MG Service Cancellation (Immediate) Ack Command/Response Initiated Information element name Information element required Information element description MG Service Cancellation (Immediate) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to FORCED. Reason M This information element indicates the reason for the command. This is set to 908 - "MG Impending Failure" or 905 - "Termination Taken OOS". MG Service Cancellation (Immediate) Ack MGC Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 40 11.13 MGC Hand-Off Table 17 shows the contents of the MGC Hand-Off and MGC Hand-Off Ack command/response pair. Table 17: MGC Hand-Off and MGC Hand-Off Ack Command/Response Initiated Information element name Information element required Information element description MGC Hand-Off MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to HANDOFF. Reason M This information element indicates the reason for the command. This is set to 903 - "MGC Directed Change". Alternate MGC Id M This is the alternate MGC Identity (see note) to which the control association should be moved. MG Hand-Off Ack MG Context M As received. Command M As received. Termination M As received. NOTE: The ServiceChangeMgcID parameter is of type Message Identifier (MID, see clause 8.3/H.248.1 [i.5]), the parameter format represents thus either an address (IP version 4 or 6 domain address; broadband MTP3 address) or a name (IP domain name or a generic device name). In both cases the parameter is used for an unambiguous identification of an MGC entity (i.e. a primary or secondary MGC). Names require firstly a resolution into a routable address. The name-to-address resolution by the MG requires a local or remote DNS query request in case of the domain format, or a local mapping table in case of the device format. Each name resolution is related to the "pre-configured list of MGC entities" in the MG see clause 11.5/H.248.1 [i.5]). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 41 11.14 MG Re-Registration (Handoff) Table 18 shows the contents of the MG Re-Registration (Handoff) and MG Re-Registration (Handoff) Ack command/response pair. Table 18: MG Re-Registration (Handoff) and MGC Re-Registration (Handoff) Ack Command/Response Initiated Information element name Information element required Information element description MG Re-Registration (Handoff) Request MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to HANDOFF. Reason M This information element indicates the reason for the command. This is set to 903 - "MGC Directed Change". Service Change Profile O Indicates the name of a supported H.248 profile. Protocol Version O Indicates the highest H.248 version supported by the MG - if other than 1. MG Re-Registration (Handoff) Ack MGC Context M As received. Command M As received. Termination M As received. Service Change Profile O This information element indicates the profile (name and version) supported by the MGC if different from that proposed by the MG. Protocol Version O If the highest protocol version supported by the MGC is lower than that proposed by the MG, this parameter must be included. If the highest protocol version supported by the MGC is equal to that proposed by the MG, this parameter may be included. Note that if the protocol version supported by the MGC is greater than that proposed by the MG, the command is rejected with an error response 406 ("Version Not Supported"). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 42 11.15 MG Termination OOS Graceful Table 19 shows the contents of the MG Termination OOS Graceful and MG Termination OOS Graceful Ack command/response pair. Table 19: MG Termination OOS Graceful and MG Termination OOS Graceful Ack Command/Response Initiated Information element name Information element required Information element description MG Termination OOS Graceful MG Context M This information element indicates the H.248 context for the command. Set to ALL, NULL or SPECIFIC (dependent on whether the termination identity is partially wildcarded or not). Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to a specific termination or a partially wildcarded identity (e.g. an E1). Method M This information element indicates the method for the command. This is set to GRACEFUL. Reason M This information element indicates the reason for the command. This is set to 905 - "Termination OOS". Service Change Delay M Indicates the period before which the MG will go out of service. MG Termination OOS Graceful Ack MGC Context M As received. Command M As received. Termination M As received. 11.16 MGC Overload Notification Table 20 shows the contents of MGC Overload Notification and MGC Overload Notification Ack command/response pair. Table 20: MGC Overload Notification and MGC Overload Notification Ack Command/Response Initiated Information element name Information element required Information element description MGC Overload Notification MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to MODIFY. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Overload Notification M This information element indicates that the MGC is in overload. MGC Overload Notification Ack MG Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 43 11.17 MG Registration Redirect Table 21 shows the contents of the MG Registration and MG Registration (Redirect) Ack command/response pair. Table 21: MG Registration Redirect Command/Response Initiated Information element name Information element required Information element description MG Registration MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to RESTART or DISCONNECTED or HANDOFF or FAILOVER. Reason M This information element indicates the reason for the command. This is set dependent on the METHOD. Service Change Profile O Indicates the name of a supported H.248 profile. Protocol Version O Indicates the highest H.248 version supported by the MG - if other than 1. MG Registration (Redirect) Ack MGC Context M As received. Command M As received. Termination M As received. Protocol Version O If the highest protocol version supported by the MGC is lower than that proposed by the MG, this parameter must be included. If the highest protocol version supported by the MGC is equal to that proposed by the MG, this parameter may be included. Note that if the protocol version supported by the MGC is greater than that proposed by the MG, the command is rejected with an error response 406 ("Version Not Supported"). Service Change Profile O This information element indicates the profile (name and version) supported by the MGC if different from that proposed by the MG. Alternate MGC Id M This element enables the MGC to inform the MG that it should redirect its Service Change to an alternative address (see note). The MG will now repeat the MG REGISTRATION (COLD BOOT) procedure to this alternate address. NOTE: See also note in table 17. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 44 11.18 User Plane Failure Table 22 shows the contents of User Plane Failure and User Plane Failure Ack command/response pair. Table 22: User Plane Failure and User Plane Failure Ack Command/Response Initiated Information element name Information element required Information element description User Plane Failure MG Context M This information element indicates the H.248 context for the command. Set to a specific value. Command M This is the H.248 Command. Set to NOTIFY. Termination M This information element indicates the H.248 termination for the command. This is set to a specific ephemeral termination identity. User Plane Failure M This information element indicates that a failure in the user plane has been detected (e.g. nt/netfail, g/cause etc.). User Plane Failure Ack MGC Context M As received. Command M As received. Termination M As received. 11.19 Root Event Notification Table 23 shows the contents of the Root Event Notification and Root Event Notification Ack command/response pair. Table 23: Root Event Notification and Root Event Notification Ack Command/Response Initiated Information element name Information element required Information element description Root Event Notification MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to NOTIFY. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. ROOT events M This information element indicates the detected ROOT event (e.g. expiry of inactivity timer, MG Overload Notification or change to IP Realm Availability). Root Event Notification ACK MGC Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 45 11.20 MG Lost Communication (Disconnected) Table 24 shows the contents of the MG Lost Communication (Disconnected) and MG Lost Communication (Disconnected) Ack command/response pair. Table 24: MG Lost Communication (Disconnected) and MG Lost Communication (Disconnected) Ack Command/Response Initiated Information element name Information element required Information element description MG Lost Communication (Disconnected) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to DISCONNECTED. Reason M This information element indicates the reason for the command. This is set to 900 "Service Restored". MG Lost Communication (Disconnected) Ack MGC Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 46 11.21 MG Lost Communication (Failover) The MG attempts to establish a new control association using its list of pre-provisioned MGC identities. The MG cycles though its list until a successful response is received. This procedure may be part of a MGC failover procedure, e.g. the MG is initiating a changeover from the original primary MGC to a next secondary MGC. Table 25 shows the contents of the MGC Failover -Establish New Control Association and MGC Failover -Establish new Control Association Ack command/response pair. Table 25: MG Lost Communication (Failover) and MG Lost Communication (Failover) Ack Command/Response Initiated Information element name Information element required Information element description MG Lost Communication (Failover) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to FAILOVER. Reason M This information element indicates the reason for the command. This is set to 909 - "MGC Impending Failure". Service Change Profile O Indicates the name of a supported H.248 profile. Protocol Version O Indicates the highest H.248 version supported by the MG - if other than 1. MG Lost Communication (Failover) Ack MGC Context M As received. Command M As received. Termination M As received. Service Change Profile O This information element indicates the profile (name and version) supported by the MGC if different from that proposed by the MG. Protocol Version O If the highest protocol version supported by the MGC is lower than that proposed by the MG, this parameter must be included. If the highest protocol version supported by the MGC is equal to that proposed by the MG, this parameter may be included. Note that if the protocol version supported by the MGC is greater than that proposed by the MG, the command is rejected with an error response 406 ("Version Not Supported"). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 47 11.22 MG Redundant Takeover (Primary) Table 26 shows the contents of the MG Redundant Takeover (Primary) and MG Redundant Takeover (Primary) Ack command/response pair. Table 26: MG Redundant Takeover (Primary) and MG Redundant Takeover (Primary) Ack Command/Response Initiated Information element name Information element required Information element description MG Redundant Takeover (Primary) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to FAILOVER. Reason M This information element indicates the reason for the command. This is set to 908 - "MG Impending Failure". MG Redundant Takeover (Primary) Ack MGC Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 48 11.23 MG Re-Registration (Restart) Table 27 shows the contents of the MG Re-Registration (Restart) and MG Re-Registration (Restart) Ack command/response pair. Table 27: MG Re-Registration (Restart) and MG Re-Registration (Restart) Ack Command/Response Initiated Information element name Information element required Information element description MG Re-Registration (Restart) MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to RESTART. Reason M This information element indicates the reason for the command. This is set to the value received from the MGC during the MGC INITIATED SERVICE RESTORATION procedure - see clause 11.9. Service Change Profile O Indicates the name of a supported H.248 profile. Service Change Version O Indicates the highest H.248 version supported by the MG - if other than 1. MG Re-Registration (Restart) Ack MG Context M As received. Command M As received. Termination M As received. Service Change Profile O This information element indicates the profile (name and version) supported by the MGC if different from that proposed by the MG. Service Change Version O If the highest protocol version supported by the MGC is lower than that proposed by the MG, this parameter must be included. If the highest protocol version supported by the MGC is equal to that proposed by the MG, this parameter may be included. Note that if the protocol version supported by the MGC is greater than that proposed by the MG, the command is rejected with an error response 406 ("Version Not Supported"). ETSI ETSI TS 183 025 V2.5.1 (2009-04) 49 11.24 Wildcarded Subtract Table 28 shows the contents of the Wildcarded Subtract and Wildcarded Subtract Ack command/response pair. Table 28: Wildcarded Subtract and Wildcarded Subtract Ack Command/Response Initiated Information element name Information element required Information element description Wildcarded Subtract MGC Context M This information element indicates the H.248 context for the command. Set to ALL. Command M This is the H.248 Command. Set to SUBTRACT or W-SUBTRACT. Termination M This information element indicates the H.248 termination for the command. This is set to ALL or a partially wildcarded identity (e.g. ip/2/*). Wildcarded Subtract Ack MG Context M As received (if W prefix used), else a list of specific context IDs. Command M As received. Termination M As received (if W prefix used), else a list of specific IDs. 11.25 MG Redundant Takeover (Secondary) Table 29 shows the contents of the MG Redundant Takeover (Secondary) and MG Redundant Takeover (Secondary) Ack command/response pair. Table 29: MG Redundant Takeover (Secondary) and MG Redundant Takeover (Secondary) Ack Command/Response Initiated Information element name Information element required Information element description MG Redundant Takeover (Secondary) MG Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to FAILOVER. Reason M This information element indicates the reason for the command. This is set to 919 - "Warm Failover" or 920 - "Cold Failover". MG Redundant Takeover (Secondary) Ack MGC Context M As received. Command M As received. Termination M As received. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 50 11.26 MGC Initiated Service Cancellation Table 30 shows the contents of the MGC Initiated Service Cancellation and MGC Initiated Service Cancellation Ack command/response pair. Table 30: MGC Initiated Service Cancellation and MGC Initiated Service Cancellation Ack Command/Response Initiated Information element name Information element required Information element description MGC Initiated Service Cancellation MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to SERVICE CHANGE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Method M This information element indicates the method for the command. This is set to FORCED. Reason M This information element indicates the reason for the command. This is set to 905 - "Termination taken out of service". MGC Initiated Service Cancellation Ack MG Context M As received. Command M As received. Termination M As received. 11.27 Void 11.28 Audit ROOT Properties This procedure is performed against the ROOT termination to enable the MGC to determine the values of any ROOT termination properties on the MG. Table 31 shows the contents of the Audit ROOT Properties and Audit ROOT Properties Ack command/response pair. Table 31: Audit ROOT Properties and Audit ROOT Properties Ack Command/Response Initiated Information element name Information element required Information element description Audit ROOT Properties MGC Context M This information element indicates the H.248 context for the command. Set to NULL. Command M This is the H.248 Command. Set to AUDIT VALUE. Termination M This information element indicates the H.248 termination for the command. This is set to ROOT. Audit Properties M This is the list of ROOT properties required to be audited by the MGC. Audit ROOT Properties Ack MG Context M As received. Command M As received. Termination M As received. Root Properties M The returned list of ROOT property values as requested by the MGC. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 51 Annex A (informative): Stage 3 Non-Call Related H.248 Procedures and their Contents This annex provides exemplar stage 3 H248 message equivalents of the procedures in clause 11. A.1 MG Registration (Cold Boot) The MG sends SERVICE CHANGE command as in table A.1. Table A.1: MG Registration (Cold Boot) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = RESTART SC Reason = 901 If applicable: H248 Profile Identity H248 Protocol Version The MGC responds as in table A.2. Table A.2: MG Registration (Cold Boot) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT If applicable:- H248 Profile Identity H248 Protocol Version An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Restart, Reason='901', Profile=ProfileName/1, Version=2}}}} Reply=1002{Context=-{ServiceChange = ROOT }} A.2 MG Restoration The MG sends SERVICE CHANGE command as in table A.3. Table A.3: MG Restoration Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = RESTART SC Reason = 900,902, 916, 917 or 918 If applicable:- H248 Profile Identity H248 Protocol Version ETSI ETSI TS 183 025 V2.5.1 (2009-04) 52 The MGC responds as in table A.4. Table A.4: MG Restoration Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT If applicable:- H248 Profile Identity H248 Protocol Version An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Restart, Reason='900', Profile=ProfileName/1, Version=2}}}} Reply=1002{Context=-{ServiceChange = ROOT }} A.3 Packages Audit The MGC sends an AUDIT VALUE request command as in table A.5. Table A.5: Packages Audit Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT Audit Packages The MG responds as in table A.6. Table A.6: Packages Audit Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT Packages List An example message exchange would be: Transaction=1002{Context=- { AuditValue=ROOT{ Audit{Packages}}}} Reply=1002{Context=-{AuditValue = ROOT {Packages { g-2,root-2, nt-1, xdd-1…….etc.}}}} ETSI ETSI TS 183 025 V2.5.1 (2009-04) 53 A.4 Context Audit A number of different context audits are possible, dependent on what information is already known and what information is required to be returned in the audit response. The MGC audits the MG by sending an AUDIT VALUE request to the MG. The required information is returned in the response. Table A.7: Context Audit Request (Termination Id known) Address Information Control information Bearer information Transaction ID = x Context ID = * OR - Termination ID = specific If required Required Audit Info Table A.8: Context Audit Request Ack (Termination Id known) Address Information Control information Bearer information Transaction ID = x Context ID = specific OR - Termination ID = specific If requested:- Audit Info An example message exchange would be: Transaction=1002{Context=* { AuditValue=aln/4{ Audit{}}}} Reply=1002{Context=12{AuditValue = aln/4}} Table A.9: Context Audit Request (Context Id known) Address Information Control information Bearer information Transaction ID = x Context ID = specific Termination ID = * OR specific If required Required Audit Info Table A.10: Context Audit Request Ack (Context Id known) Address Information Control information Bearer information Transaction ID = x Context ID = specific Termination ID = specific If requested:- Audit Info An example message exchange would be: Transaction=1002{Context=12 { AuditValue=*{ Audit{}}}} Reply=1002{Context=12{AuditValue = aln/4, AuditValue=ephemeral/23}} ETSI ETSI TS 183 025 V2.5.1 (2009-04) 54 Table A.11: Context Audit Request (Termination Id partially wildcarded) Address Information Control information Bearer information Transaction ID = x Context ID = * Termination ID = Partially Wildcarded If required Required Audit Info Table A.12: Context Audit Request Ack (Termination Id partially wildcarded) Address Information Control information Bearer information Transaction ID = x Context ID = specific (list) Termination ID = specific (list) If requested:- Audit Info An example message exchange would be: Transaction=1002{Context=* { O-AuditValue=tdm/e1_3/*{ Audit{ }}}} Reply=1002{Context=12{AuditValue = tdm/e1_3/4}, Context=15{AuditValue=tdm/e1_3/12}, Context=23{AuditValue=tdm/e1_3/21}} Table A.13: Context Audit Request (to obtain context list) Address Information Control information Bearer information Transaction ID = x Context ID = * Termination ID = ROOT Table A.14: Context Audit Request Ack (to obtain context list) Address Information Control information Bearer information Transaction ID = x Context ID = specific (list) Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=* { W-AuditValue=ROOT{ Audit{ }}}} Reply=1002{Context=10{AuditValue = ROOT}, Context=24{AuditValue=ROOT}, Context=45{AuditValue=ROOT}} A.5 MG Termination Available The MG sends SERVICE CHANGE command as in table A.5.1. Table A.15: MG Termination Available Request Address Information Control information Bearer information Transaction ID = x Context ID = - OR specific Termination ID = Specific or Partially Wildcarded SC Method = RESTART SC Reason = 900 ETSI ETSI TS 183 025 V2.5.1 (2009-04) 55 The MGC responds as in table A.16. Table A.16: MG Termination Available Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = Specific or Partially Wildcarded An example message exchange would be: Transaction=1002{Context=- { ServiceChange=aln/1{ Services{Method=Restart, Reason='900'}}}} Reply=1002{Context=-{ServiceChange = aln/1}} A.6 MG Termination Unavailable The MG sends SERVICE CHANGE command as in table A.17. Table A.17: MG Termination Available Request Address Information Control information Bearer information Transaction ID = x Context ID = - OR * OR specific Termination ID = Specific or Partially Wildcarded SC Method = FORCED SC Reason = 904-907, 910, 912-915 The MGC responds as in table A.18. Table A.18: MG Termination Available Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = Specific or Partially Wildcarded An example message exchange would be: Transaction=1002{Context=- { ServiceChange=aln/1{ Services{Method=Forced, Reason='905'}}}} Reply=1002{Context=-{ServiceChange = aln/1}} A.7 Audit Termination State The MGC sends an AUDIT VALUE command as in table A.19. Table A.19: Audit Termination State Request Address Information Control information Bearer information Transaction ID = x Context ID = - OR * OR specific Termination ID = Specific or Partially Wildcarded Audit Service State ETSI ETSI TS 183 025 V2.5.1 (2009-04) 56 The MG responds as in table A.20. Table A.20: MG Termination Available Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - OR specific Termination ID = Specific or Partially Wildcarded Service State An example message exchange would be: Transaction=1002{Context=- { AuditValue=aln/1{ Audit{Media{TerminationState{ServiceState}}}}}} Reply=1002{Context=-{AuditValue = aln/1{ServiceState=InService}}} A.8 Set ROOT Termination Events/Properties The MGC sends a MODIFY request command as in table A.21. Table A.21: Set ROOT Events/Properties Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT If required: Set Inactivity Timer Request Overload Notification The MG responds as in table A.22. Table A.22: Set ROOT Events/Properties Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { Modify=ROOT{ Events{it/ito{mit=30000}, ocp/mg_overload}}}} Reply=1002{Context=-{Modify = ROOT}} A.9 MGC Initiated Service Restoration The MGC sends SERVICE CHANGE command as in table A.23. Table A.23: MGC Initiated Service Restoration Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = RESTART SC Reason = 900 or 901 ETSI ETSI TS 183 025 V2.5.1 (2009-04) 57 The MG responds as in table A.24. Table A.24: MGC Initiated Service Restoration Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Restart, Reason='901'}}}} Reply=1002{Context=-{ServiceChange = ROOT}}} A.10 Check MG Availability The MGC sends an AUDIT VALUE command as in table A.25. Table A.25: Audit Termination State Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT The MG responds as in table A.26. Table A.26: MG Termination Available Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { AuditValue=ROOT{ Audit{}}}} Reply=1002{Context=-{AuditValue = ROOT}} A.11 MG Service Cancellation (Graceful) The MG sends SERVICE CHANGE command as in table A.27. Table A.27: MG Service Cancellation (Graceful) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = GRACEFUL SC Reason = 905, 908 Service Change Delay ETSI ETSI TS 183 025 V2.5.1 (2009-04) 58 The MGC responds as in table A.28. Table A.28: MG Service Cancellation (Graceful) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Graceful, Reason='908', Delay=600}}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.12 MG Service Cancellation (Immediate) The MG sends SERVICE CHANGE command as in table A.29. Table A.29: MG Service Cancellation (Immediate) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = FORCED SC Reason = 905, 908 The MGC responds as in table A.30. Table A.30: MG Service Cancellation (Immediate) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Forced, Reason='905'}}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.13 MGC Hand-Off The MGC sends SERVICE CHANGE command as in table A.31. Table A.31: MGC Hand-Off Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = HANDOFF SC Reason = 903 SC MGCId = Alternate MGCId ETSI ETSI TS 183 025 V2.5.1 (2009-04) 59 The MG responds as in table A.32. Table A.32: MGC Hand-Off Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be (see note): Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Handoff, Reason='903', MgcIdToTry=1.2.3.4}}}} Reply=1002{Context=-{ServiceChange = ROOT}} NOTE: The ServiceChangeMgcID parameter is of type "IP version 4 address". The parameter value provides a port-less IP address, i.e. the well-known port (2944 for text, 2945 for binary encoding) is used at the redirected IP interface. A.14 MG Re-Registration (Handoff) The MG sends SERVICE CHANGE command as in table A.33. Table A.33: MG Re-Registration (Handoff) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = HANDOFF SC Reason = 903 If applicable:- H248 Profile Identity H248 Protocol Version The MGC responds as in table A.34. Table A.34: MG Re-Registration (Handoff) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT If applicable:- H248 Profile Identity H248 Protocol Version An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Handoff, Reason='903', Profile=ProfileName/1, Version=2}}}} Reply=1002{Context=-{ServiceChange = ROOT }} ETSI ETSI TS 183 025 V2.5.1 (2009-04) 60 A.15 MG termination OOS (Graceful) The MG sends SERVICE CHANGE command as in table A.35. Table A.35: MG Termination OOS Graceful Request Address Information Control information Bearer information Transaction ID = x Context ID = * OR specific OR - Termination ID = specific OR Partially Wildcarded SC Method = GRACEFUL SC Reason = 908 Service Change Delay The MGC responds as in table A.36. Table A.36: MG Termination OOS Graceful Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = * OR specific OR - Termination ID = Specific OR partially wildcarded An example message exchange would be: Transaction=1002{Context=34{ ServiceChange=aln/16{ Services{Method=Graceful, Reason='908', Delay=600}}}} Reply=1002{Context=34{ServiceChange = aln/16}} A.16 MGC Overload Notification The MGC sends a MODIFY request command as in table A.37. Table A.37: MGC Overload Notification Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT Overload Notification The MG responds as in table A.38. Table A.38: MGC Overload Notification Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { Modify=ROOT{ Media{TerminationState{etsi_nr=1.34}}}}} Reply=1002{Context=-{Modify = ROOT }} ETSI ETSI TS 183 025 V2.5.1 (2009-04) 61 A.17 MG Registration Redirect The MG sends SERVICE CHANGE command as in table A.39. Table A.39: MG Registration Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = RESTART or DISCONNECTED or HANDOFF or FAILOVER SC Reason = 901 or others If applicable:- H248 Profile Identity H248 Protocol Version The MGC responds as in table A.40. Table A.40: Registration Redirect Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT Alternate MGC Address (see note) If applicable:- H248 Profile Identity H248 Protocol Version NOTE: See also note in table 11.13-1. An example message exchange would be (see note): Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Restart, Reason='901', Profile=ProfileName/1, Version=2}}}} Reply=1002{Context=-{ServiceChange = ROOT {Services { MGCIdToTry=1.2.3.4}}}} NOTE: The ServiceChangeMgcID parameter is of type "IP version 4 address". The parameter value provides a port-less IP address, i.e. the well-known port (2944 for text, 2945 for binary encoding) is used at the redirected IP interface. A.18 User Plane Failure During call related procedures, the MGC has previously armed for the nt/netfail event. If so, and user plane failure is detected by the MG, then the MG sends a NOTIFY request command as in table A.41. Table A.41: User Plane Failure Address Information Control information Bearer information Transaction ID = x Context ID = specific Termination ID = specific Network Failure ETSI ETSI TS 183 025 V2.5.1 (2009-04) 62 The MGC responds as in table A.42. Table A.42: User Plane Failure Ack Address Information Control information Bearer information Transaction ID = x Context ID = specific Termination ID = specific An example message exchange would be: Transaction=1002{Context=1 { Notify=ephemeral/2{ ObservedEvents{nt/netfail{stream=1}}}}} Reply=1002{Context=1 {Notify = ephemeral/2}} A.19 Root Event Notification The MG sends a NOTIFY request command as in table A.43. Table A.43: Root Event Notification Address Information Control information Bearer information Transaction ID = x Context ID= - Termination ID = ROOT Notified ROOT Event The MGC responds as in table A.44. Table A.44: Root Event Notification Request ACK Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be : Transaction=1002{Context=- { Notify=ROOT{ ObservedEvents{it/ito}}}} OR Transaction=1002{Context=- { Notify=ROOT{ ObservedEvents{ocp/mg_overload}}}} OR Transaction=1002{Context=- { Notify=ROOT{ ObservedEvents{ipra/arc{nar=[“1”,”5”]}}}}} Reply=1002{Context=-{Notify = ROOT }} A.20 MG Lost Communication (Disconnected) The MG sends a SERVICE CHANGE command as in table A.45. Table A.45: MG Lost Communication (Disconnected) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = DISCONNECTED SC Reason = 900 ETSI ETSI TS 183 025 V2.5.1 (2009-04) 63 The MGC responds as in table A.46. Table A.46: MG Lost Communication (Disconnected) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Disconnected, Reason='900'}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.21 MG Lost Communication (Failover) The MG sends SERVICE CHANGE command as in table A.47. Table A.47: MG Lost Communication (Failover) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = FAILOVER SC Reason = 909 If applicable:- H248 Profile Identity H248 Protocol Version The MGC responds as in table A.48. Table A.48: MG Lost Communication (Failover) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT If applicable:- H248 Profile Identity H248 Protocol Version Alternate MGC Address (see note) NOTE: See also note in table 17. An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Failover, Reason='909', Profile=ProfileName/1, Version=2}}}} Reply=1002{Context=-{ServiceChange = ROOT }} ETSI ETSI TS 183 025 V2.5.1 (2009-04) 64 A.22 MG Redundant Takeover (Primary) The MG sends SERVICE CHANGE command as in table A.49. Table A.49: MG Redundant Takeover (Primary) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = FAILOVER SC Reason = 908 The MGC responds as in table A.50. Table A.50: MG Redundant Takeover (Primary) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Failover, Reason='908'}}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.23 MG Re-Registration (Restart) The MG sends SERVICE CHANGE command as in table A.51. Table A.51: MG Re-Registration (Restart) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = RESTART SC Reason = 900 or 901 If applicable:- H248 Profile Identity H248 Protocol Version The MGC responds as in table A.52. Table A.52: MG Re-Registration (Restart) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT If applicable:- H248 Profile Identity H248 Protocol Version ETSI ETSI TS 183 025 V2.5.1 (2009-04) 65 An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Restart, Reason="901", Profile=ProfileName/1, Version=2 }}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.24 Wildcarded Subtract The MGC sends a SUBTRACT or W-SUBTRACTcommand as in table A.53. Table A.53: Wildcarded Subtract Address Information Control information Bearer information Transaction ID = x Context ID = * Termination ID = * OR partially wildcarded The MG responds as in table A.54. Table A.54: Wildcarded Subtract Ack Address Information Control information Bearer information Transaction ID = x Context ID = * Termination ID = * OR partially wildcarded An example message exchange would be: Transaction=1002{Context=* { W-Subtract=*{ Audit{}}}} Reply=1002{Context=*{Subtract= *}} A.25 MG Redundant Takeover (Secondary) The MG sends SERVICE CHANGE command as in table A.55. Table A.55: MG Redundant Takeover (Secondary) Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = FAILOVER SC Reason = 919, 920 The MGC responds as in table A.56. Table A.56: MG Redundant Takeover (Secondary) Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT ETSI ETSI TS 183 025 V2.5.1 (2009-04) 66 An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Failover, Reason='919'}}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.26 MGC Initiated Service Cancellation The MGC sends a SERVICE CHANGE command as in table A.57. Table A.57: MGC Initiated Service Cancellation Request Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT SC Method = FORCED SC Reason = 905 The MG responds as in table A.58. Table A.58: MGC Initiated Service Cancellation Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT An example message exchange would be: Transaction=1002{Context=- { ServiceChange=ROOT{ Services{Method=Forced, Reason='905'}}}} Reply=1002{Context=-{ServiceChange = ROOT}} A.27 Void A.28 Audit ROOT Properties The MGC sends an AUDIT VALUE request command as in table A.59. Table A.59: Audit ROOT Properties Request Address Information Control information Bearer information Transaction ID = x Context ID= - Termination ID = ROOT Audit ROOT Properties The MG responds as in table A.60. Table A.60: Audit ROOT Properties Request Ack Address Information Control information Bearer information Transaction ID = x Context ID = - Termination ID = ROOT ROOT Properties ETSI ETSI TS 183 025 V2.5.1 (2009-04) 67 An example message exchange would be: Transaction=1002{Context=- { AuditValue=ROOT{ Audit{Media{TerminationState{root/*}}}}}} Reply=1002{Context=-{AuditValue = ROOT { Media{TerminationState {root/maxNumberOContexts=1000, root/maxTerminationsPerContext=2, root/normalMGExecutionTime=2, root/normalMGCExecutionTime=2, root/MGProvisionalResponseTimerValue=5, root/MGCProvisionalResponseTimerValue=5, root/MGCOriginatedPendingLimit=10, root/MGOriginatedPendingLimit=10}}}}} ETSI ETSI TS 183 025 V2.5.1 (2009-04) 68 Annex B (informative): Relation of the H.248 ServiceStates Property Model with Management Models This annex provides an example for mapping H.248 ServiceStates to a management state model and vice versa. B.1 Introduction The majority of H.248 procedures are independent of the management plane, i.e. "interactionless" procedures. However some procedures should consider potential interaction aspects between control plane (here H.248) and management plane. Such interactions might be loosely coupled like in case of provisioning or pre-provisioning activities, but there are also some more tightly coupled interactions, particularly in the area of the ServiceChange Command. For instance, certain actions, which are resulting in H.248 or management state changes, may result in correspondent state changes in the management or H.248 model respectively. B.2 Scope The scope of the present document is only on the H.248 ServiceStates Property state model. The H.248 ServiceChange Command model (see annex F ITU-T Recommendation H.248.1 [i.5]) is not considered. The indicated management technologies and correspondent management state models are just examples. There are many other possibilities in mapping the H.248 ServiceStates Property on dedicated management state models. From that perspective, the present document may assist to correlate such management state models with the H.248 ServiceStates Property. The present document provides an example mapping between the H.248 ServiceStates Property states and management plane state models according ITU-T Recommendation X.731 [i.12] and RFC 4268 [i.11]. Other management plane models could be used as well for correlation with the H.248 ServiceStates Property states. For such models the documented mapping could be used as guideline. B.3 Mapping between Models B.3.1 Example Management Models It is proposed to consider the management models from ITU-T Recommendation X.731 [i.12] and RFC 4268 [i.11] as example. One reason for a management model using ITU-T and IETF technologies is related to the origins of H.248 in these two standardization development organizations (SDO). Another motivation is the fact that RFC 4268 [i.11] refers explicitly to ITU-T Recommendation X.731 [i.12] and provides already an aligned management model (on top level). Management models are typically distinguishing three different basic state models, which are related to the three primary factors that are affecting the management state of a managed object with regard to its corresponding resources' availability: operability, administration and usage. The correspondent three basic management state models could be combined. The correlation with the H.248 ServiceStates Property with a single basic management state model (from RFC 4268 [i.11]), i.e. the operational state model, administrative state model or usage state model, may be used as starting point, but is typically not sufficient, e.g. when considering interactions between H.248 procedures and management procedures. For this reason is a combined management state model proposed, based on the combination of operational and administrative states, see table B. 1. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 69 Table B.1: Basic Model Relations Relation of H.248 ServiceStates Property Model with Management Models Control State Model ITU-T Recommendation H.248 Management State Models ITU-T Recommendation X.731 [i.12] / RFC 4268 [i.11] ServiceStates Property ↔ Operational State Administrative State Usage State In-Service ↔ Enabled Unlocked ⎯ Out-of-Service ↔ Disabled Unlocked ⎯ Out-of-Service ↔ Enabled Locked ⎯ Out-of-Service ↔ Disabled Locked ⎯ See note 1 ↔ Enabled Shutting Down ⎯ Test ↔ See note 2 See note 2 ⎯ NOTE 1: There is no explicit state modelled. "Test" is rather indicated via status attributes, which are used to qualify operational, administrative or usage states. Relevant in case of test might be the availability status attribute "in test", or the control status attributes "subject to test" or "reserved for test". NOTE 2: There is no explicit state modelled concerning H.248 ServiceStates Property. There might be a transient state in the H.248 ServiceChange Command model, but this is out of scope here. Other mapping schemes are principally possible. B.4 Interaction Aspects Purpose of this clause is to illustrate principle interaction between management use cases and H.248 procedures. Only a few examples are shown. A comprehensive list of all potential interaction aspects is out of scope of the present document. B.4.1 Effect of H.248 Actions on Management Models Some ServiceChange procedures may affect the H.248 ServiceStates Property. For instance, the ServiceStates Property of a physical Termination could be changed from In-Service to Out-of-Service with a ServiceChangeMethod of "Forced" or "Graceful" and ServiceChangeReason #905 ("Termination taken out of service"), see clause F.3.10.2 of [i.5]. Such a ServiceStates Property change may lead to a state transition in the management model from {enabled, unlocked} to {disabled, unlocked} when using the sample mapping of clause 3.2. That means that the operational state would change. Such a state change in the management model would be visible for the management system, but would not lead to a notification of the management system because the operational state is read-only in nature (see clause 7.1.1 of ITU-T Recommendation X.731 [i.12]). B.4.2 Effect of Management Model State Transition on H.248 Model Only management actions in the areas of configuration management and/or fault management may principally have an interaction with the H.248 ServiceStates Property. B.4.2.1 Configuration management The management action is triggering an H.248 ServiceChange procedure. The management action may lead to a state transition in the management model, and also to a correspondent change of the H.248 ServiceStates Property. See also clause 10. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 70 B.4.2.2 Fault management There are not any effects here because the flow of information is typically from the managed entity towards the management systems (see also next clause). B.4.3 Effect of failures in H.248 entities on State Transition in Management Model and H.248 Model Such a failure scenario in an H.248 entity itself is triggering. See also clause 10. 1) an H.248 ServiceChange procedure; and also 2) a notification (e.g. alarm) of the management system. There may be correspondent state transitions in the management model and the H.248 ServiceStates Property model. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 71 Annex C (informative): Change history Change history Date WG Doc. CR Rev CAT Title / Comment Curren t Versio n New Version 01-07-08 18WTD229r1 012 F Editorial changes and corrections 2.2.0 2.2.1 01-07-08 18WTD230r1 013 F Changes to Disable Termination procedure 2.2.0 2.2.1 07-08 TB approval of CRs 012 and 013 2.2.1 2.3.0 23-09-08 18bTD160r1 014 F Addition of new procedure for MG Resources Change 2.3.0 2.3.1 14-11-08 TB approval of CR 014 2.3.1 2.4.0 23-02-09 20WTD108r1 015 F Clarification to clause 10.2 2.4.0 2.4.1 23-02-09 20WTD109r1 016 F Clarification to clause 10.13 2.4.0 2.4.1 Publication 2.4.1 2.5.1 ETSI ETSI TS 183 025 V2.5.1 (2009-04) 72 History Document history V2.0.0 July 2007 Publication as TR 183 025 V2.0.0 V2.2.0 June 2008 Publication as TR 183 025 V2.2.0 V2.5.1 April 2009 Publication
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1 Scope
The present document specifies the architecture and functions of an IPTV system that makes use of the NGN IMS architecture and its features, implementing the requirements defined in TS 181 014 [14] and TS 181 016 [15]. The present document has taken IPTV solutions defined by other organizations (such as DVB, ATIS IIF, etc.) into account. It is based on an IMS based architecture and where appropriate the aforementioned solutions are referenced. By relying on common components the resulting architecture can coexist with other TISPAN NGN services. NOTE: As the use of IPTV services may release personal data the provider of IPTV services is expected to comply with relevant privacy protection principles as specified for Identity Management in the NGN in TS 187 016 [19].
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2 References
References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the reference document (including any amendments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity.
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2.1 Normative references
The following referenced documents are necessary for the application of the present document. [1] ETSI ES 282 001: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); NGN Functional Architecture". [2] ETSI TS 182 006: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IP Multimedia Subsystem (IMS); Stage 2 description [3GPP TS 23.506 Release 8, modified]". [3] ETSI ES 282 004: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); NGN Functional Architecture; Network Attachment Sub-System (NASS)". [4] ETSI TS 133 220: "Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Generic Authentication Architecture (GAA); Generic Bootstrapping Architecture (GBA) (3GPP TS 33.220)". [5] ETSI TS 187 003: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); NGN Security; Security Architecture". [6] ETSI TS 102 034: "Digital Video Broadcasting (DVB); Transport of MPEG-2 TS Based DVB Services over IP Based Networks". [7] ITU-T Recommendation P.10/G.100: "Vocabulary for performance and quality of service " - New Appendix I - Definition of Quality of Experience (QoE). [8] ETSI ES 282 003: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Resource and Admission Control Sub-System (RACS): Functional Architecture". ETSI ETSI TS 182 027 V3.5.1 (2011-03) 12 [9] ETSI TS 183 004: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); PSTN/ISDN simulation services: Communication Diversion (CDIV); Protocol specification". [10] ETSI TS 182 008: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Presence Service; Architecture and functional description [Endorsement of 3GPP TS 23.141 and OMA-AD-Presence-SIMPLE-V1-0]". [11] ETSI ES 282 007: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IP Multimedia Subsystem (IMS); Functional architecture". [12] Void. [13] ETSI ES 283 030: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Presence Service Capability; Protocol Specification [3GPP TS 24.141 V7.0.0, modified and OMA-TS-Presence-SIMPLE-V1-0, modified]". [14] ETSI TS 181 014: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Requirements for network transport capabilities to support IPTV services". [15] ETSI TS 181 016: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Service Layer Requirements to integrate NGN services and IPTV". [16] ETSI TS 122 340: "Universal Mobile Telecommunications System (UMTS); IP Multimedia Subsystem (IMS) messaging; Stage 1 (3GPP TS 22.340 version 7.0.0 Release 7)". [17] ETSI TS 123 237: "Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia Subsystem (IMS) Service Continuity; Stage 2 (3GPP TS 23.237 Release 9)". [18] ETSI TS 124 237: "Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia (IM) Core Network (CN) subsystem IP Multimedia Subsystem (IMS) service continuity; Stage 3 (3GPP TS 24.237 Release 9)". [19] ETSI TS 187 016: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); NGN Security; Identity Protection (Protection Profile)". [20] Void.
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2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. [i.1] DSL Forum Technical Report TR-126: "Triple-play Services Quality of Experience (QoE) Requirements". [i.2] Void. [i.3] ETSI ES 282 010: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Charging management [Endorsement of 3GPP TS 32.240 Release 7, 3GPP TS 32.260 Release 7, 3GPP TS 32.297 Release 7, 3GPP TS 32.298 Release 7 and 3GPP TS 32.299 Release 7, modified]". [i.4] ETSI TR 182 005: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Organization of user data". [i.5] ETSI ES 204 915 (all parts): "Open Service Access (OSA); Application Programming Interface (API); (Parlay 6)". [i.6] ETSI ES 202 504 (all parts): " Open Service Access (OSA); Parlay X Web Services; (Parlay X 3)". ETSI ETSI TS 182 027 V3.5.1 (2011-03) 13 [i.7] ETSI TS 129 198 (all parts): "Universal Mobile Telecommunications System (UMTS); LTE; Open Service Access (OSA) Application Programming Interface (API) (3GPP TS 29.198 Release 7)". [i.8] ETSI TS 123 002: "Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Network architecture (3GPP TS 23.002 Release 8)". [i.9] ETSI TS 123 218: "Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia (IM) session handling; IM call model; Stage 2 (3GPP TS 23.218 Release 8)". [i.10] 3GPP TR 23.810: "Technical Specification Group Services and System Aspects; Study on Architecture Impacts of Service Brokering; (Release 8)". [i.11] Toshiro Nunome; Shuji Tasaka, "An Application-Level QoS Comparison of Inter-Destination Synchronization Schemes for Continuous Media Multicasting", IEICE transactions on communications, ISSN 0916-8516, Vol. 87 (2004), No. 10, pp. 3057-3067 (11). [i.12] SCTE-130 part 1: "Advertising Systems Overview". [i.13] SCTE-130 part 2: "Core Data Elements". [i.14] SCTE-130 part 3: "Ad Management Service interface". [i.15] OMA MobAd 1.0 RD: "Mobile Advertising Requirements". [i.16] OMA MobAd 1.0 AD: "Mobile Advertising Architecture". [i.17] Void. [i.18] ITU-T Recommendation J.181: "Digital program insertion cueing message for cable television systems". [i.19] ETSI TS 129 199 (all parts): "Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Open Service Access (OSA); Parlay X web services; (3GPP TS 29.199 version 8.1.0 Release 8)". [i.20] ETSI TS 126 234: "Universal Mobile Telecommunications System (UMTS); LTE; Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols and codecs (3GPP TS 26.234 Release 8)".
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3 Definitions and abbreviations
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3.1 Definitions
For the purposes of the present document, the following terms and definitions apply: content control: procedure for controlling content delivery NOTE: e.g. starting content delivery, playback of content (such as pause, fast and slow playback, reverse playback. rewinding, jumping forwards or backwards), stopping content delivery), and content management (e.g. digital rights management, program scheduling management, delivery management. content delivery: procedure for delivering multimedia contents content Provider: entity that owns or is licensed to sell content or content assets content protection: protection of content or content assets during its entire lifetime NOTE: The content provider defines the lifetime that the protection is required for. Inter-destination Media Synchronization (IDMS): feature for exchanging arrival time and delay information, resulting in substantial synchronisation of the media outputs of two or more UEs, as presented to their users ETSI ETSI TS 182 027 V3.5.1 (2011-03) 14 IPTV Service Access History (SAH): collection of a user's service states and service actions as well as other information NOTE: Examples include accessed service types, watched content and time of watching. IPTV content identifier: superclass of the identifiers that identify content in specific IPTV services IPTV Service Action Data (SAD): persistent record of actions that a user has made; for use in access to IPTV services NOTE: Examples include BC bookmarks, available CoD, PVR items and UGC items. IPTV service state: snapshot of the information related to an ongoing IPTV service NOTE: Examples include the current BC program ID, the ID of current CoD content, the state of PVR recordings, the media state of services and invoked trick play events, commercial breaks in services and combinations of these. IPTV Service State Data (SSD): information about IPTV service state and service actions NOTE 1: This information may be held in network elements that constitute the IPTV solution or external applications. NOTE 2: The relationship between SSD, SAD and SAH is as follows: SSD is information about the present meant for immediate use, e.g. inserting a targeted advertisement or performing an action on an incoming phone call. SAD is information meant for future service access, e.g. a user setting and later retrieving a BC bookmark to see (again) the bookmarked content. SAH is information meant for user preference extraction and sharing services, e.g. for service personalization, targeting, and sharing consumption history among authorized users. IPTV Service protection: managing authorized access to the IPTV-service; the protection of IPTV-content (e.g. files or streams) and IPTV-service information during delivery which may include content already protected and meta data that the service provider adds to the content NOTE: The IPTV service may be composed of the content to be transfered and other data and service components. Service protection addresses protecting this composition while in transit and regulates authorized access to the service. Additionally it addresses ensuring the service availability, as defined in the service level agreements. IPTV service type identifier: identifies type of IPTV services media stream identifier: identifier carried in a unicast or multicast media stream that identifies that specific media stream offset: value indicating the elapsed time between the beginning of content and the current reading position of the reading cursor in that same streamed content park TV: feature that would enable a user (on a UE) make an impulsive request to record ongoing BC service/programme from a particular point in time NOTE: This recording point is also referred to as a bookmark. park and pickup TV: feature that would enable a user (on a UE) to Park TV and subsequently Pickup TV pickup TV: feature that would enable a user (on a UE) retrieve or request BC service/programme that was recorded and bookmarked via an impulsive record request NOTE: The IPTV content can be retrieved from the bookmarked location or recording point on same or different UE at a later point in time. programme: entry in the Electronic Programme Guide ETSI ETSI TS 182 027 V3.5.1 (2011-03) 15
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3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply: ADM Ad Management Service ADS Ad Decision Service AS Application Server BC BroadCast CIS Content Information Service CM Content marker CoD Content on Demand C-PVR Client Personal Video Recorder CR Content Recommendation CRS Content Recommendation Service CSF Content Security Functions ECF Elementary Control Function EF Elementary Functions EFF Elementary Forwarding Function EPG Electronic Programme Guide GAA Generic Authentication Architecture GBA Generic Bootstrapping Architecture HD High Definition ICM Incoming Call Management IDMS Inter-Destination Media Synchronization IGMP Internet Group Management Protocol IMPU IMS Public User Identity IMS IP Multimedia Subsystem IPTV IP Television MCF Media Control Function MCN Media Channel Negotiation MDF Media Delivery Function MF Media Function MSAS Media Synchronization Application Server NASS Network Attachment SubSystem NGN Next Generation Network N-PVR Network-Personal Video Recorder PC Parental controlled POIS Placement Opportunity Information Service PSC Personalized Service Composition PVR Personal Video Recorder QoE Quality of Experience QoS Quality Of Service RACS Resource and Admission Control Subsystem SAD Service Action Data SAH Service Access History SC Synchronization Client SCF Service Control Function SCIM Service Capability Interaction Manager SCS Service Capability Server SD Standard Definition SDF Service Discovery Function SIP Session Initiation Protocol SIS Subscriber Information Service SKMF Service Key Management elementary Functions SLF Subscription Locator Function SMF Service Membership elementary Functions SPF Service Protection elementary Functions SSC Shared Service Control SSD Service State Data SSF Service Selection Function TAI Targeted Advertisement Insertion ETSI ETSI TS 182 027 V3.5.1 (2011-03) 16 TPF Transport Processing Functions UE User Equipment UGC User Generated Content UPSF User Profile Server Function URI Uniform Resource Identifier XDMS XML Document Management Server
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4 High-level overview
User Equipment Application Functions & IPTV Service Functions Core IMS User Profiles Manage- ment Functions Content Provider Functions Media Delivery, Distribution & Storage Transport Control Functions Transport Processing Functions Transport Functions Figure 1: High level functional architecture for IMS-based IPTV NOTE 1: The specification of management functions and content provider functions is considered out of scope of the present document. User equipment UE: The IPTV enabled UE terminates the IPTV control and media signals, and displays the corresponding information to the user. The UE interaction with the user allows selection of programme, content, and service descriptions, such as content guides for broadcast and VoD services. Application functions and IPTV service functions Enables operation of or provides IPTV services. This includes IPTV Service Supporting Functions. ETSI ETSI TS 182 027 V3.5.1 (2011-03) 17 IPTV Service Supporting Function: The IPTV Service Supporting Function defined here are those common functions which could support or be used by other IPTV service or applications. NOTE 2: Examples of IPTV service supporting functions may be Service Discovery and Selection functions. User Profiles User Profiles includes user data that are involved in providing IPTV services. Core IMS It provides functionality for authentication, authorization, and signalling for the setup of the service provisioning and content delivery. It routes signalling messages to the appropriate application server or triggers the applications based on settings maintained in the UPSF. For resource reservation and admission control this function interacts with the RACS. Transport Functions Transport Control: contains functions from RACS and NASS. It provides policy control, resource reservation and admission control as well as IP address provisioning, network level user authentication and access network configuration as defined in TISPAN. Transport Processing Functions (TPF): represents network access links and IP core. The IP core is in charge of data transmission with quality of service support. Media Delivery, Distribution and Storage The Media Delivery, Distribution and storage function receives and stores live feeds and media streams coming into the IPTV System from Content Providers. It is mainly in charge of media processing, delivery, storing, trans-coding and relaying. This function performs all these tasks along with the control of - or feedback to the IPTV Service and Control. Content protection may also be performed here or already protected content could be delivered over these functionalities.
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5 Overview of functional entities
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5.1 Functional architecture for IPTV services
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5.1.1 Functional architecture overview
The overall functional architecture for IPTV service is shown in figure 2. ETSI ETSI TS 182 027 V3.5.1 (2011-03) 18 Figure 2: Functional architecture for IPTV services NOTE 1: Only Xc and Xd are explicitly shown as traversing the Transport Processing Functions. For the sake of simplicity other reference points are only shown as end to end. In figure 2, the IPTV Service Control Functions, the IPTV Media Functions, the Service Selection Function (SSF) and the Service Discovery Function (SDF) fit in the context of TISPAN NGN Functional Architecture Release 2 [1]. NOTE 2: To support the regionalized delivery of content and metadata in accordance with applicable regulations, at least one of the service layer entities involved in the IPTV service should query the UE location from the NASS and enforce the regionalization. As stated in [2], the IMS architecture shall be based on the principle that the service control for Home subscribed services for a roaming subscriber is in the Home network. This principle shall be applied also in case the IPTV solution supports roaming.
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5.1.2 IPTV services
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5.1.2.0 Compliance
An IPTV solution is compliant to the present document if the following points are fulfilled. • All mandatory services and features are implemented as specified in the present document. • If an optional service or feature is implemented, then it is implemented as specified in the present document. • If an optional service or feature is implemented, and the present document specifies multiple options, then it is implemented according to at least one or those options. Transport Control Functions Core IMS Transport Processing Functions IPTV Media Functions Xc Xd Gm Gq' Xa ISC e2 UPSF Cx e4 RACS NASS UE IPTV Media Control Functions (MCF) IPTV Media Delivery Functions (MDF) Sh Ut y2 Sh ISC Xp Media Delivery, Distribution & Storage Transport Functions Application and IPTV Service Functions SDF SSF Ss’ IPTV Service Control Functions (SCF) ETSI ETSI TS 182 027 V3.5.1 (2011-03) 19 The IMS based IPTV architecture in this release should be fully backward compatible with architecture and services specified in previous release. NOTE: Any backwards compatibility issues need to be explicitly mentioned. 5.1.2.1 General IPTV services execution involves three functions: a service control function (SCF), a media control function (MCF) and a media delivery function (MDF). An SCF may host the logic of one or more of the following services as defined in TS 181 016 [15]: The following table 1 provide list of services and feature supported by TISPAN IMS based IPTV architecture (selection based on [1] and procedures described in TISPAN): NOTE: In certain cases, TS 181 016 [15] provides insufficient guidance with respect to the mandatory/optional nature of services. If a service has been specified as "mandatory" within the Service Layer Requirements specification but the corresponding requirements have not been clearly mandated, the service has been specified as "Optional" or "Mandatory/Optional" (with appropriate qualifying Note) within table 1. Table 1: IPTV services and features supported by TISPAN IMS based IPTV subsystem NGN IPTV Service and Feature TISPAN R2 Service Layer Requirements to Integrate NGN Services and IPTV TISPAN R2 IPTV Architecture; IPTV functions supported by the IMS subsystem TISPAN R3 Service Layer Requirements to Integrate NGN Services and IPTV TISPAN R3 IPTV Architecture; IPTV functions supported by the IMS subsystem Specification TS 181 016 [15] Release 2 TS 182 027 Release 2 TS 181 016 [15] Release 3 TS 182 027 Release 3 Linear/ Broadcast TV M M M M Linear/ Broadcast TV with Trick Play M O M O Time Shifted TV O O O O Content on Demand (CoD) M M M M Push CoD NA NA O O Network PVR M M/O (see note 2) M M/O (see note 2) Client PVR NA NA O O (See NOTE 2) Audio M O M O Pay-Per-View NA NA M O Interactive TV NA NA M O Service discovery M M M M Service Information (EPG) M M M M Parental Control M M/O (see note 3) M M/O (see note 3) User Profiling and Personalization O O O O Communications and Messaging NA NA O O Notifications NA NA O O IPTV Presence O O O O Interaction between users NA N/A O O Interaction with NGN services O O O O Advertising M M (see note 4) M M (see note 4) Targeted Advertising NA NA O O User Generated Content NA NA M O Internationalization O O O O Content recommendation NA NA O O Games NA NA O O Picture NA NA O O Bookmarks NA NA O O Personalized channel NA NA O O Personalized Service Composition NA NA O O ETSI ETSI TS 182 027 V3.5.1 (2011-03) 20 NGN IPTV Service and Feature TISPAN R2 Service Layer Requirements to Integrate NGN Services and IPTV TISPAN R2 IPTV Architecture; IPTV functions supported by the IMS subsystem TISPAN R3 Service Layer Requirements to Integrate NGN Services and IPTV TISPAN R3 IPTV Architecture; IPTV functions supported by the IMS subsystem Service Portability NA NA O O Service Continuation between IPTV UEs NA NA O O Service Continuation fixed-mobile NA NA O O Remote Control of IPTV services NA NA O O Emergency Information. NA NA O O Interaction with 3rd Party application (e.g. Parlay) NA NA O O Service synchronization NA NA O O Incoming call management NA NA O O NOTE 1: M - Mandatory, O- Optional, NA - not available or not specified (out of scope in release) in architecture NOTE 2: It is recommended that at least one type of PVR is supported by the IPTV system. NOTE 3: Mandating this feature is subject to local regulatory policies. NOTE 4: Advertising refers to traditional broadcast based advertising services which impose no new requirements on IMS based IPTV subsystem. The service request/response messages between the UE and the SCF are transferred via the Core IMS. Media Control messages are exchanged between the UE and the MCF via the Xc reference point. Media Data is exchanged between UE and MDF via the Xd reference point. For UGC services, media may also be exchanged or streamed between users provided that the control of this media exchange or these media streams lies with the UGC function. For CR services, the SCF exchanges service request/response messages with the UE directly over the Ut or via the IMS Core as appropriate.
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5.1.3 Functional entities
Refer to clause 5.1.5.
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5.1.3A Generic Capabilities
IPTV Generic IPTV Capabilities: 1. service discovery and selection 2. service control 3. service interaction 4. media control 5. media delivery 6. content protection 7. content management and distribution 8. interactions with other NGN services ETSI ETSI TS 182 027 V3.5.1 (2011-03) 21
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5.1.4 Elementary Functions (EF)
General: 1. network attachment 2. registration 3. resource Management 4. charging information IPTV elementary functions: Service related elementary functions 5. service discovery 6. service authorization 7. service selection 8. service initiation 9. service control 10. service information handling (e.g. metadata) 11. service configuration Session related elementary functions 12. session initiation 13. session modification 14. session termination Service Protection related elementary functions 15. service key triggering function Multimedia delivery and control related elementary functions 16. multicast based media delivery (media streaming) 17. unicast based media delivery (media streaming) 18. content download/upload (offline content transfer) 19. control of multicast based media streaming 20. control of unicast based media streaming) 21. control of content transfer by download/upload 22. content ingestion (receiving content) 23. content recording(capture of live content) 24. content storage 25. content adaptation (e.g. transcoding, mix, substitute, personalize) Content management related elementary functions 26. content acquisition 27. content validation ETSI ETSI TS 182 027 V3.5.1 (2011-03) 22 28. content distribution Content protection related elementary functions 29. content licencing 30. content key management 31. content encryption NOTE: Content protection solutions are not standardised by TISPAN but a framework allowing for implementation of multiple solutions is provided by the TISPAN architecture. User data management related elementary functions 32. User profile/data management 33. Accounting/right control IPTV Common elementary functions: 34. Status/state (changes) detection/reporting 35. Common notification 36. Messaging 37. Presence Reporting 38. Inter-destination Media synchronization
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5.1.4.1 Content Security Functions (CSF)
Content security elementary functions are described in clause 10.2.
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5.1.5 Functional Entities
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5.1.5.1 Service Discovery and Selection Functions (SDF and SSF)
The Service Discovery Function (SDF) and Service Selection Function (SSF) are functions which provide information necessary to the UE to select an IPTV service. Tasks of the SDF: • Generates and/or provides the service attachment information. • Provides personalized service discovery. The service attachment information consists of SSF addresses in the form of URIs and/or ip-addresses. Tasks of the SSF: • Provides the service selection information, e.g. a list of available services that the UE can then browse and select. The SSF may optionally generate this service selection information. It may also retrieve and forward the service selection information. - Provides personalized service selection information and/or information needed to personalize the service selection. This must be delivered via unicast mode. (See note 1 regarding multicast options.) - Provides non-personalized service selection data. This can be delivered via multicast or unicast mode. • Optionally provides service selection presentation information. This presentation information may be personalized when it is delivered over unicast mode. Optionally receives selection request from UE, e.g. an N-PVR content capture request as described in clause 8.5. ETSI ETSI TS 182 027 V3.5.1 (2011-03) 23 NOTE 1: The way the service selection information might be personalized when it is delivered via multicast mode is out of scope for this release. However, specified below is a non exhaustive list of high-level options to achieve such personalization: Using the SDF: when processing a request from a particular user/UE, the SDF could redirect the user/UE to specific multicast addresses/SSFs corresponding to the category to which the user belongs. This would imply that users/UEs are classified into specific categories. Using the SCF: UE could fetch IPTV user profile information in the form of BC Service ID listings from the SCF. This may be encoded as XML document(s) via the Ut reference point using XCAP-like mechanism or as HTML document with possibly embedded scripts to filter this service selection data. This IPTV user profile information may then be used to locally filter the service selection data that was previously delivered via multicast mode. NOTE 2: EPG is defined in TS 181 016 [15]. For each IPTV service, the following data is provided: • An identifier associated to the IPTV service: this identifier is used by service control functions and media functions to identify the requested content when processing service initiation requests. In case of a CoD service, the identifier identifies exactly one content item. In case of a BC service, the BC identifier, which is the Service Package Id related to BC profile defined in clause 7.3, identifies a set of channels among which the user can switch. • Optionally the set of network parameters that may be required by the UE to activate a service (e.g. the extra information that may be needed by the UE to establish content delivery channels and content control channels). • User readable data related to the IPTV service.
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5.1.5.2 IPTV Service Control Functions (SCF)
Tasks of SCF: • Service authorization during session initiation and session modification, which includes checking IPTV users' profiles in order to allow or deny access to the service. • Credit limit and credit control (using the on-line charging systems ES 282 010 [i.3]). In addition, the SCF performs the following tasks depending on type of service supported • Select the relevant IPTV media functions (see clause 5.2). • Send relevant notifications to the MF, e.g. for content recommendation service. • For Push CoD Services, initiate media content (e.g. recorded BC program, CoD content) download to UE. • Select appropriate ad content for specific user or user group, based on user profile (e.g. user preference, shopping habits, location information, etc.) and IPTV service status (e.g. current BC program ID, commercial break in BC service or pause during CoD content playback). • Communicate with an external advertising sub-system in order to make ad-selection and ad-placement decisions if one exists (see annexes E and F). • For SCF-managed TAI, send ad insertion indication to MF or UE. • Instruct the UE to perform trick play commands, e.g. pause a TV channel, CoD or N-PVR stream. • Initiate BC and/or CoD session to UE for immediate consumption. • Generate playlist information and communicate it to the MF. • For Content Recommendation Services, detect CRS event and generate CRS information for specific user or user group, based on user profile (e.g. user preference). ETSI ETSI TS 182 027 V3.5.1 (2011-03) 24 • Detect an event, based on some criteria, trigger relevant internal service logic and send a notification to the UE or other applications associated with the specific user. • Optionally, for PVR service, initiate the recording of content, e.g. for C-PVR service, initiates a notification request to UE to start recording. • For restricted trick play, acquire restriction policy and transmit to relevant MF. • Detecting IPTV service state information. • Optionally, aggregating (i.e. collecting and storing) requested IPTV service state information. The SCF is a SIP Application Server (AS). An IPTV SCF belonging to an IMS network managed by another provider shall not have direct access to user profile data in the UPSF via the Sh reference point; it may however have access to user profile data by other means (e.g. Rg reference point to GUP), depending on the NGN operator's implementation and capabilities. The SCF may use the IPTV profile in order to customize the user experience. For instance, the list of subscribed BC TV Services could be used to filter the information sent to the UE. The User Equipment communicates with the IPTV Service Control Functions via the Core IMS for the purpose of session management, and may be using the Ut reference point for the purpose of service profile configuration. In the latter case, an authentication proxy may sit between the User Equipment and the SCF.
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5.1.5.3 IPTV Media Control and Delivery Functions (MCF and MDF)
IPTV Media Functions are in charge of controlling and delivering the media flows to the UE. They are split into Media Control Functions (MCF) and Media Delivery Functions (MDF). Tasks of Media Control Function (MCF): • Handling media flow control of MDF. • May manage the media processing of MDF. • Monitoring the status of MDF. • Managing interaction with the UE (e.g trick mode commands). • Handling interaction with the IPTV service control function SCF. • Keeping an accurate view on status and content distribution related to the different MDFs that it controls. • Detecting IPTV service state information. • Reporting IPTV service state information to SCF when requested. • Selecting an MDF, in the case an MCF controls multiple MDFs different criteria, may be applicable (as described e.g. for CoD in clause 5.2). • Selecting MF, return the selection result to SCF and Redirect sessions to the selected MF (e.g. in case the requested content is not available on this MF or for load balancing among MFs). • Generate charging information, e.g. for end-user charging based on the viewed content. • Handle ad insertion control of MDF, i.e. control the fetching of the ad content and synchronization between ad content and IPTV content, including accounting for delay or drift in broadcast TV schedules. • In case of live User Generated Content consumption (TS 181 016 [15], clause A.13), there is a direct relationship on the media delivery and media control levels between downstreaming and upstreaming UGC sessions, which both terminate at the MCF. The MCF ensures that session descriptions of the downstreaming and upstreaming UGC sessions match. UE's subscribed to the particular Live UGC are notified when this Live UGC starts. ETSI ETSI TS 182 027 V3.5.1 (2011-03) 25 Tasks of MDF: • Handling media flows delivery (for delivering multimedia services to user). • Status reporting to MCF (e.g. reporting on established IPTV media streams). • Store of media (e.g. CoD assets) and may also store some service information stored with media for IPTV services. • In particular, it may be used for storage for the most frequently accessed content or user specific content (e.g. recording PVR, Time-shift TV, BC service with Trick mode, user generated content) if the same tasks are not performed by UE. • May additionally process, encode or transcode (if required) media to different required media formats (e.g. TV resolution depending on terminals capabilities or user preferences). • May perform content protection functionalities (e.g. content encryption). • May support content ingestion of IPTV media. NOTE 1: Ingested content can either be processed, encoded or transcoded in an MDF, or it can arrive in a suitable media format for delivery to UE, thus avoiding transcoding. • MDF may act as source for multicast streams of IPTV services e.g. BC or UGC media streams. • For UGC services, receiving content from UE through an upstreaming/upload media channel. • May collect QoE reports (e.g. from UE using Xd). • For Push CoD Services, handling content download (download CoD content to UE or record BC live stream and then download to UE). • Perform ad insertion during IPTV content playback, i.e. deliver ad content to the UE during the ad insertion time, either exclusively or in parallel with the IPTV content. • Recognize appropriate in-band /out-of-band Ad insertion indicators (eg-cue messages as defined in ITU-T Recommendation J.181 [i.18]), when present. These Ad insertion indicators define positions within the IPTV content where advertisement content can be inserted /replaced. This task may be done by coordination with an external advertising sub-system. • For personalized stream composition, the MDF may support alternative streams for use with an existing broadcast channel or CoD item, e.g. alternative video, audio or subtitle tracks. NOTE 2: To enhance QoE evaluation quality, QoE reports may additionally be collected from other sources than the UE. However, this is beyond the scope of the present document. To support QoE, the UE may send QoE reports via Xd concerning the quality of the IPTV Media Data received. Each IPTV Service Control Function uses the ISC reference point to communicate with the NGN Core IMS. As stated in TS 182 006 [2], an Application Server may originate requests to a destination without involving the S-CSCF. This capability should be used in case the SCF is to communicate with the media function without involving the core-IMS. Each corresponding IPTV Media Function communicates with the UE over Xc and Xd for Media Control and Media Delivery. For each service, the corresponding Media Control entities communicate with the UE on the Xc reference point and control the appropriate Media Data Delivery entities which send the Media Data to the UE on the Xd reference point. ETSI ETSI TS 182 027 V3.5.1 (2011-03) 26
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5.1.5.4 UPSF
The UPSF holds the IMS user profile and possibly IPTV specific profile data (see clause 7). It communicates with IPTV Service Control Functions at the Sh reference points and with the Core IMS at the Cx reference point as defined in ES 282 007 [11]. When multiple instances of a UPSF exist, the Core IMS and the IPTV Service Control Functions may use the services of a Subscription Locator Function (SLF) to fetch the address of the UPSF. The SLF communicates with IPTV Service Control Functions at the Dh reference points and with the Core IMS at the Dx reference point as defined in ES 282 007 [11]. For the sake of simplicity the SLF and associated reference points are not shown on figure 2. NOTE: The IMS principle procedures, such as security, authentication process, are also considered to be applied to this IPTV functional architecture and the procedures, unless explicitly stated otherwise.
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5.1.5.5 Transport processing functions
IPTV services make use of generic transport processing functions defined in ES 282 001 [1]. 5.2 Interactions between Service Control function and Media Functions The relationship between Service Control Function (SCF) and Media Function (MF), composed of Media Control Function and Media Delivery Function, is shown in figure 3. Figure 3: Relationship between Service Control Function and Media Functions When an MF is involved in a session (e.g. CoD) the specific MF for this particular session will be determined during the session initiation and resource allocation procedure. This determination may be based on the following criteria: • Location of the UE. • Status information of all the available media functions (e.g. online or offline, media processing capability, available resources in the different -MF holding the same contents, etc.). • Load of the different MF holding the same contents. • Content identity of the requested content; It is recommended that the structure of the content identifiers be designed so as to facilitate this selection, without requiring parsing the full identifier. The selection process relies on elementary functions that can be hosted in an SCF and/or an MCF. In the latter case the MCF may act as a redirect server to redirect sessions to another MCF. And in some cases, the selection task of SCF -SCF MCF MDF MDF CoD -MCF MF ETSI ETSI TS 182 027 V3.5.1 (2011-03) 27 and/or MCF may become very simple. For e.g. if a Request-URI for service/content identifier corresponds to just one MCF, then SCF and/or MCF may just transfer the session to the unique MCF. NOTE 1: The location of the selection process in a separate entity is out of scope for this release. NOTE 2: Admission control procedures for use of transport resources at the CoD-MF side are out of scope for this release. The SCF shall contact the MCF during the session initiation and resource allocation phase. The SCF may contact several MCFs before its determination. TheSCF contacts the MCF via the Core IMS as shown in figure 4. Figure 4: Reference points between SCF and MCF When the MCF is contacted, it shall respond with the parameters offer for the session corresponding to the content required by the UE. The MCF controls one or several MDFs. Tasks of the MCF are the following: • Select an MDF. • Control the media stream resources in the MDFs. • Interpret information coming from the SCF and control the MDFs accordingly. • Generate of CDRs. Selection of the MDF by the MCF uses similar criteria to the selection of a MCF by a SCF. And in some cases, the selection task of MCF may become very simple. For e.g. if a Request-URI for service/content identifier corresponds to just one MDF, then MCF may just transfer the session to the unique MDF. After the MCF has selected a MDF for service, it may communicate with the MDF. If the MDF is not functional for some reason, the MCF may detect this exception, for example, by a local response timeout, and select another MDF with the requested content. If there is no other MDF with the requested content under the MCF's control, it should redirect the service request to another MCF or return an appropriate error message to the SCF.
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5.3 Void
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5.4 Inter-destination media synchronization
Inter-destination media synchronization is an optional generic capability, aimed at servicing requiring this capability, see TS 181 016 [15], clause A.9.6 for examples. The Media Synchronization Application Server (MSAS) and Synchronization Client (SC) are functions that provide inter-destination media synchronization. These functions are used for synchronization sensitive services for which IPTV delays and delay differences may spoil the quality of experience. The functional entities and reference point of the synchronization mechanism are shown in figure 4A. SCF CORE-IMS MCF ISC y2 ETSI ETSI TS 182 027 V3.5.1 (2011-03) 28 Media Synchronization Application Server (MSAS) Sync Synchronization Client (SC) Figure 4A: Functional entities and reference points for inter-destination media synchronization
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5.4.1 Functional entities MSAS and SC
The inter-destination media synchronization (IDMS) mechanism uses the concept of synchronization sessions. Each synchronization session involves a Media Synchronization Application Server (MSAS) and multiple Synchronization Clients (SC). A synchronization session is used for the inter-destination synchronization of IPTV content (a BC channel, CoD, UGC, etc.) by exchanging synchronization status information (i.e. arrival time information) and delay information in the form of synchronization settings instructions. • Synchronization status information: timing information on media reception at each SC. • Synchronization settings instruction: instruction how much an SC should delay themedia stream . Tasks of the SC: • Setting up and accepting synchronization sessions with/from the MSAS. • Sending synchronization status information to the MSAS. • Receiving delay information in the form of synchronization settings instructions from the MSAS. • Delaying (buffering) a media stream according to the received synchronization settings instruction. Tasks of the MSAS: • Session-oriented tasks: - Setting up and accepting synchronization sessions with/from SCs. • Media-oriented tasks: - Collecting synchronization status information from SCs. - Calculating delay information and the derived synchronization settings instructions for the SCs. - Distributing synchronization settings instructions to SCs. The MSAS function may be decomposed in session-oriented functions and media-oriented functions. NOTE: Examples of algorithms to calculate the synchronization settings instructions from collected synchronization status information may be found in [i.11].
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5.4.2 Mapping onto the IPTV architecture
The synchronization architecture can be mapped onto the IPTV architecture in the following ways. Mapping 1: SC in UE • The session-oriented part of the MSAS is an elementary function of the SCF. For synchronisation using a direct communication channel between multiple UEs, the MSAS is co-located with the SC in a UE. • The SC is an elementary function of the UE. ETSI ETSI TS 182 027 V3.5.1 (2011-03) 29 • The Sync reference point is tunnelled over the Gm and ISC reference points. • Each synchronization session is associated with an IPTV session. Mapping 2: SC in Transport • The MSAS is an elementary function of the SCF or a stand-alone Application Server. • The SC is an elementary function of the Transport Functions. NOTE 1: Mapping 1 is aimed at small-scale deployments of services that require media synchronization and only a limited number of UEs uses media synchronization. It reuses existing IPTV sessions. Mapping 2 is aimed at large-scale deployment of media synchronization. NOTE 2: In mapping 2, the SC is an adjunct function that may be co-resident with any of the appropriate elements in the transport layer.
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5.4.3 Modification and re-origination of media streams
In addition to inter-destination media synchronization, additional synchronisation measures are needed in case a media stream is modified or re-originated during transport. Examples of these are transcoding, HD-to-SD conversion and user-generated comments to a live broadcast. In such cases, additional media-stream-modifying Synchronisation Clients (SC') are placed at the functional entities where media streams are modified, see figure 4B. The Sync' reference point is used to exchange convey synchronization status correlation information between from the media-stream-modifying SC' and to the MSAS on the synchronicity relationship between incoming and outgoing media streams. • Synchronization correlation information: timing information on the synchronicity relationship between incoming and outgoing media streams at an SC'. Figure 4B: Media synchronization in case of media stream modification SC MSAS Media stream origination (e.g. MF or EFF) Media stream modification (e.g. transcoder at MF or re-origination at UE) SC' Media stream destination (e.g. UE or TFP) SC Sync Sync' Media stream M Media stream M' ETSI ETSI TS 182 027 V3.5.1 (2011-03) 30