[5MBUSA] User Service Announcement parameters alignment and clarifications
Source: BBC | Work Item: 5MBUSA | Category: F (Correction) | Release: Rel-17 | Spec: TS 26.502 v17.11.0
During 5G-MAG reference implementation of MBS User Services, multiple gaps and ambiguities were identified between the stage 2 definition (TS 26.502) and the stage 3 specification (TS 26.517). This CR corrects TS 26.502 to align with TS 26.517 and resolve implementation issues.
Conformance Profiles – New parameter added to MBS Distribution Session (table 4.5.6-1) and MBS Distribution Session Announcement (table 4.5.8-1), assigned by the MBS Application Provider, referencing profiles defined in clause 12.
Transport Security Protection – Clarified that the flag is provisioned by the MBS Application Provider or (for the User Service Announcement Channel) by the MBSF. Assigner column in table 4.5.6-1 updated accordingly.
Object Acquisition Identifiers – MIME Type – Each identifier may now be accompanied by a content type; this is mandatory when the identifier is an Application Service Entry Point locator. MBSTF shall verify content type on ingest. Impacts tables 4.5.6-2 and 4.5.8-2.
Object Repair Back-off Parameters – New parameter defined in both MBS Distribution Session (table 4.5.6-2) and MBS Distribution Session Announcement (table 4.5.8-2), assigned by the MBSF. Clarified that Object Repair is enabled at MBSF discretion (not provisioned by MBS Application Provider); wording changed from "provisioned" to "enabled" throughout clauses 4.2.6 and 4.5.6.
New Reference Point MBS-1 – Formally defined in clause 4.4.1: exposure of composite User Service Announcement from MBSF to MBS Application Provider for private advertisement via MBS-8. Referenced in procedures (clauses 5.2 and 5.4).
User Service Advertisement Notification – Clarified in table 4.6.2-1 and clause 5.4 that the "User Service advertisement" event includes a URL for the MBS Application Provider to retrieve the full User Service Announcement bundle (not just partial information) via reference point MBS-1 when external delivery mode is indicated.
4.2.2, 4.2.6, 4.3.1, 4.3.2, 4.4.1, 4.5.2, 4.5.6, 4.5.8, 4.6.2, 5.2, 5.4, 6.1
TS 26.580, TS 26.581; potential impact on TS 29.580 (Nmb10/Nmb5, CT3) and TS 29.581 (Nmb2, CT4) for items 1–3 and 5–6.
Stage 2/stage 3 misalignment for MBS User Services, blocking correct reference implementation.