[MB-SMF] SBI: MBS Session Create Service operation

[Borjis131]

Following 3GPP TS 29.532 - Release 17.4.0

Ch. 5.3.2.2 - MBS Session Create Service operation

Other references:
3GPP TS 29.537 - TS29537_Npcf_MBSPolicyAuthorization.yaml

[Borjis131]

MBS Session Service API needs TS29537_Npcf_MBSPolicyAuthorization.yaml OpenAPI spec file from 5G System; Multicast/Broadcast Policy Control services; Stage 3 to be built.

Using 3GPP TS 29.537 - Release 17.2.0

[Borjis131]

To send the MBS Session Create request from the AF, to create a broadcast MBS Session with a previously allocated TMGI:

# MBS Session Create request: /nmbsmf-mbssession/v1/mbs-sessions
curl --http2-prior-knowledge \
  --request POST \
  --header "Content-Type: application/json" \
  --data '{ "mbsSession": { "mbsSessionId": { "tmgi": { "mbsServiceId": "XXXXXX", "plmnId": { "mcc":"001", "mnc":"01" } } }, "serviceType":"BROADCAST" } }' \
  smf.open5gs.org:80/nmbsmf-mbssession/v1/mbs-sessions

Filling "mbsServiceId": "XXXXXX" with the received MBS Service Id from the TMGI Allocate request.

To send the MBS Session Create request from the AF, to create a multicast MBS Session without a preallocated TMGI:

# MBS Session Create request with TMGI allocate: /nmbsmf-mbssession/v1/mbs-sessions
curl --http2-prior-knowledge \
  --request POST \
  --header "Content-Type: application/json" \
  --data '{ "mbsSession": { "tmgiAllocReq": true, "serviceType":"MULTICAST" } }' \
  smf.open5gs.org:80/nmbsmf-mbssession/v1/mbs-sessions

[Borjis131]

From TS 23.247 Rel 18.3.0:
Source specific IP multicast address or TMGI may be used as MBS Session ID in NAS messages exchange between a UE and a CN when the UE requests to join/leave a Multicast MBS session. For multicast MBS sessions that the UE joined with a source specific IP multicast address, a TMGI is also allocated by 5GC and is sent to the UE and used in other signalling messages between RAN, CN and UE. Details see clause 7.2.1.3.

For multicast MBS sessions, a source specific IP multicast address can be assigned by external AFs.
The source specific IP multicast address is used to identify an Multicast MBS session and consists of two IP addresses, one is an IP unicast address used as source address in IP packets for identifying the source of the multicast service (e.g. AF/AS), the other is an IP multicast address used as destination address in related IP packets for identifying a multicast communication service associated with the source.