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Content for  TS 23.479  Word version:  18.0.0

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0…   5…   5.6…   5.11…

 

5.11  Open mediap. 22

5.11.1  Generalp. 22

This subclause specifies the open media to start the reception of a given media delivered over an MBMS subchannel.
With this API function, header decompression and FEC decoding can be performed by the MC MBMS user agent or by the MC application.
This API function allows two methods to return the media from the MC MBMS user agent to the MC application: by providing them on a local network interface or by returning them with a callback mechanism.
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5.11.2  Proceduresp. 22

The procedure specified in Figure 5.11.2-1 allows the consumption of a media delivered over MBMS.
Pre-conditions:
  • The MC application is registered towards the MC MBMS user agent
  • A MBMS bearer has been announced to the MC application through the MBMS procedures specified in TS 23.280 and registered toward the MC MBMS user agent.
  • This MBMS bearer is available within the UE location.
  • The MC application has received a MapGroupToBearer message (see TS 23.379, Table 10.10.1.1-1 for MCPTT and TS 23.281, Table 7.10.1.2-1 for MCVideo).
Reproduction of 3GPP TS 23.479, Fig. 5.11.2-1: Open media procedure
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Step 1.
The MC application asks to access to the communication with the open media request, by indicating the TMGI of the MBMS bearer and a list of media description information. If the MC application requests FEC decoding and/or header decompression, relevant FEC and ROHC information are included within the open media request; if the MC application wants the media packets to be returned by callback, the MC application provides a callback listener.
Step 2.
The MC MBMS user agent checks if the MBMS bearer of the media is available and starts its reception.
Step 3.
When the media is available, the MC MBMS user agent sends an open media response to the MC application, including a description of the required media (which can be with or without FEC decoding). If packets are returned to the MC application through a local network interface, this network interface name is included in the response.
Step 4.
The MC MBMS user agent makes the media streams available to the MC application according to the configured method for returning media with a help of a local network interface, or by returning the media packets to the callback listener provided in step 1.
Post-conditions:
  • The MC application can consume the required media, until interruption if the MBMS bearer becomes unavailable, or until it closes the media with the close media procedure.
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5.11.3  Information flowsp. 23

5.11.3.1  Open media requestp. 23

Table 5.11.3.1-1 describes the information flow for the open media request.
Information Element Status Description
TMGIMTMGI information of the announced MBMS bearer
Media descriptionODescribes the multicast IP adresses and ports of the requested media. (e.g. the MBMS subchannel)
FEC informationOFEC information if the MC application requests the MC MBMS user agent to perform the FEC decoding
ROHC informationOROHC information for the requested media. Indicates if header decompression by the MC MBMS user agent is requested
CallbackODedicated callback listener where to return the received media packets. If this IE is not present, the media packets are returned over a local network interface
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5.11.3.2  Open media responsep. 24

Table 5.11.3.2-1 describes the information flow for the open media response.
Information Element Status Description
Media identifierMIdentifier from the open media request
Response codeMIndicates if the open media request was successful, otherwise an error code
MessageOAdditional details
Media descriptionODescription of opened media, including the multicast IP address and port of the media, after FEC decoding
Network interfaceOThe local network interface, identified by the name of a network interface card, where the given media can be consumed by the MC application, if packet are forwarded to the MC application over a local network interface according the configured method for media reception
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5.12  Close mediap. 24

5.12.1  Generalp. 24

This subclause specifies the close media invoked by the MC application to stop the reception of a given media.

5.12.2  Proceduresp. 24

Figure 5.12.2-1 illustrates the procedure for close media.
Pre-conditions:
  • The MC application is consuming a media, after having called the open media procedure.
  • The MC application has received a UnMapGroupToBearer message (see TS 23.379, table 10.10.1.2 -1 for MCPTT and TS 23.281, table 7.10.1.3-1 for MCVideo).
Reproduction of 3GPP TS 23.479, Fig. 5.12.2-1: Close media procedure
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Step 1.
The MC application asks the MC MBMS user agent to stop the reception of media streams with the close media request.
Step 2.
The MC MBMS user agent stops the possible header decompression and FEC decoding.
Step 3.
The MC MBMS user agent notifies the MC application that the media has been closed.
Post-conditions:
  • The closed media streams are no more available to the MC application.
  • If no other media from this MBMS bearer are opened, the MC MBMS user agent can end the reception of this MBMS bearer.
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5.12.3  Information flowsp. 25

5.12.3.1  Close media requestp. 25

Table 5.12.3.1-1 describes the information flow for the close media request.
Information Element Status Description
Media identifierMIdentifier from the open media request
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5.12.3.2  Close media responsep. 25

Table 5.12.3.2-1 describes the information flow for the close media response.
Information Element Status Description
Media identifierMIdentifier from the open media request
Response codeMIndicates if the close media request was successful, otherwise an error code
MessageOAdditional details
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5.13  Retrieve capabilityp. 25

5.13.1  Generalp. 25

This subclause defines API function of retrieve capability.
The retrieve capability request is an API function call and retrieve capability response is returned with a list of capabilities.
The MC application uses this API function call to query what capabilities (e.g. FEC and ROHC) are supported by the MC MBMS user agent.

5.13.2  Proceduresp. 26

Figure 5.13.2-1 illustrates the procedure of retrieve capability.
Pre-conditions:
  • The MC application has registered towards the MC MBMS user agent.
Reproduction of 3GPP TS 23.479, Fig. 5.13.2-1: Retrieve capability procedure
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Step 1.
The MC application sends a request to query the capabilities of the MC MBMS user agent.
Step 2.
A retrieve capability response is returned with a list of available capabilities.
Post-conditions:
  • The MC application can further decide whether or not to use these capabilities of the MC MBMS user agent for subsequent communication.

5.13.3  Information flowsp. 26

5.13.3.1  Retrieve capability requestp. 26

The retrieve capability request does not have input parameters.

5.13.3.2  Retrieve capability responsep. 26

Table 5.13.3.2-1 describes the information flow for the retrieve capability response.
Information Element Status Description
FECMFEC capability of the MC MBMS user agent
ROHCMROHC capability of the MC MBMS user agent
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$  Change historyp. 27


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