Content for TS 26.517 Word version: 18.4.0
7 Packet Distribution Method
7.1 General
7.2 Re-using MBMS Delivery Method as Packet Distribution Method
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7 Packet Distribution Method p. 31
7.1 General p. 31
The Packet Distribution Method reuses different delivery concepts from TS 26.346. Additional distribution methods may be defined in future.
7.2 Re-using MBMS Delivery Method as Packet Distribution Method p. 31
7.2.1 General p. 31
The Packet Distribution Method combines three different delivery methods of TS 26.346 (namely the MBMS Streaming Delivery Method, Group Communication Delivery Method and Transparent Delivery Method) into a single distribution method, with a set of modifications.
For the Packet Distribution Method, the MBSTF may handle the ingested content on two different protocol layers according to the operating mode provisioned for the MBS Distribution Session:
- Proxy mode: The MBSTF handles UDP packet payloads and forwards UDP packet payloads from ingest into the MBS Distribution Session. The MBSTF may use different UDP ports for the MBS Distribution Session. The MBSTF re-uses the Proxy Mode of the Transparent Delivery Method as defined in clause 8B of TS 26.346.
- Forward-only mode: The MBSTF receives complete IP packets and forwards the ingested packets as MBS PDUs. The MBSTF re-uses the Group Communication Delivery Method as defined in clause 8A of TS 26.346 and the Forward-Only Mode of the Transparent Delivery Method as defined in clause 8B of TS 26.346.
7.2.2 Void
7.2.3 Session Description p. 31
7.2.3.1 General p. 31
The Session Description document contains the needed information to activate the reception of a Packet Distribution Method. The Session Description document is formatted according to the Session Description Protocol RFC 8866. The Session Description document for the Packet Distribution Method is based on the Session Description parameters as defined in clauses 8.3, 8A.3 and 8B.3 of TS 26.346 with the following restrictions and extensions.
Restrictions:
- The Mode of MBMS bearer per media parameter (clauses 8.3.1.5 and 8B.3.2 of TS 26.346) shall not be used.
- The QoE Metrics (as defined in clauses 8.3.2.1 and 8.4 of TS 26.346) shall not be used.
- ROHC header compression (as defined in clauses 8A.4 and 8B.4 of TS 26.346) shall not be used.
- The Alternative TMGI (clause 7.3.2.12 of TS 26.346) shall not be used.
- The Start time and End time of the session (SDP t line) shall indicate a superset of the active times specified in the MBS Schedule Description metadata unit, if present in the service schedule descriptions of the MBS Distribution Session (see clause 5.2.7). If there is no service schedule specified, both values of the SDP t-line should be set to zero indicating undefined times.
- When the MBS User Service is of MBS Service Type Broadcast or when an MBS User Service of type Multicast uses a TMGI as its MBS Session ID, the MBS service type of MBS Session declaration attribute as defined in clause 6.2.2.2 shall be present in the Session Description.
7.2.3.2 SDP examples for Packet Distribution Method p. 32
Below is a full example of SDP description describing the media streams part of an MBS Packet Distribution session for RTP streaming:
v=0 o=ghost 2890844526 2890842807 IN IP4 192.168.10.10 s=3GPP MBS Packet Distribution SDP Example i=Example of MBS Packet Distribution SDP file u=http:// |
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The following is a full example of SDP description for transparent streaming with two MPEG-2 Transport Streams:
v=0 o=ghost 2890844526 2890842807 IN IP4 192.168.10.10 s=3GPP MBS Transport-only SDP Example i=Example of MBS transport-only SDP file u=http:// |
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