Content for  TS 26.348  Word version:  17.1.0

Top   Top   None   None   Next
0…   5…   A…


0  Introductionp. 5

The present document defines a northbound interface between the BM-SC and the content provider. The interface is called xMB. Both external (3rd party) content providers and 3GPP defined API invokers e.g. GCS AS can use the xMB reference point to access BM-SC provided delivery services.
The xMB reference point supports different session types, such as generic file delivery e.g. for MCData, application streaming, including DASH streaming, RTP ingest and ingest for transparent delivery. The xMB reference point supports unicast delivery of content, e.g. for devices outside of the MBMS coverage area.
The xMB reference point is fully integrated into the Common API Framework for 3GPP Northbound APIs (CAPIF).

1  Scopep. 6

The present document provides interaction methods and interfaces between a BM-SC and a content provider. The purpose of the document is the definition of enablers for the usage of MBMS delivery.

2  Referencesp. 6

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
  • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
  • For a specific reference, subsequent revisions do not apply.
  • For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
TR 21.905: "Vocabulary for 3GPP Specifications".
TS 26.346: "Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs".
TS 26.234: "Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols and codecs".
TS 26.247: "Transparent end-to-end Packet-switched Streaming Service (PSS); Progressive Download and Dynamic Adaptive Streaming over HTTP (3GP-DASH)".
TS 33.310: "Network Domain Security (NDS); Authentication Framework (AF)".
RFC 6347:  "Datagram Transport Layer Security Version 1.2", E. Rescorla, N. Modadugu.
RFC 4918:  "HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)", L. Dusseault.
RFC 5795:  "The Robust Header Compression (ROHC) Framework".
RFC 3095:  "RObust Header Compression (ROHC): Framework and four profiles: RTP, UDP, ESP, and uncompressed".
TS 23.222: "Common API Framework for 3GPP Northbound APIs".
draft-wright-json-schema-01:  "JSON Schema: A Media Type for Describing JSON Documents", April 15, 2017.
TS 23.280: "Common functional architecture to support mission critical services; Stage 2".
TS 29.061: "Interworking between the Public Land Mobile Network (PLMN) supporting packet based services and Packet Data Networks (PDN)".
TS 29.468: "Group Communication System Enablers for LTE (GCSE_LTE); MB2 reference point; Stage 3".
RFC 5234  (January 2008): "Augmented BNF for Syntax Specifications: ABNF", D. Crocker and P. Overell.
TS 23.246: "Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional description".
TS 26.501: "5G Media Streaming (5GMS); General description and architecture".

3  Definitions and abbreviationsp. 7

3.1  Definitionsp. 7

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

3.2  Abbreviationsp. 7

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.
5G Media Streaming
Allocation and Retention Priority
Broadcast-Multicast - Service Centre
Dynamic Adaptive Streaming over HTTP
Datagram Transport Layer Security
Forward Error Correction
Guaranteed Bitrate
HTTP Live Streaming
Media Presentation Description
QOS Class Identifier
Quality of Service
Quality of Experience
Receive Only Mode
Real-Time Streaming Protocol
Real Time Transport Protocol
Real Time Transport Control Protocol
Service Announcement Channel
Service Area Identity
Service Capability Exposure Function
Session Description protocol
Transport Layer Security
User Equipment
User Datagram Protocol
Uniform Resource Locator
Universal Time Coordinated

4  Architecturep. 7

4.1  Generalp. 7

As shown in Figure 4.1-1, the reference point between Content Provider and BM-SC is called the xMB interface. Using the xMB reference point, content provider can invoke procedures supported by BM-SC(s) to set up and manage MBMS user service from BM-SC to the MBMS Clients. BM-SC defines an endpoint with all supported procedures on the xMB interface, which can then be converted to SGmb procedures for the interface between BM-SC and MBMS GW (not depicted).
Copy of original 3GPP image for 3GPP TS 26.348, Fig. 4.1-1: The xMB reference model
Figure 4.1-1: The xMB reference model
(⇒ copy of original 3GPP image)
The BM-SC may forward the received content for unicast delivery for appropriate functions (e.g., MBMS user service fallback).
The control plane (xMB-C) and the user plane (xMB-U) may be optionally terminated by 3GPP defined enabler / exposure functions such as an SCEF, which exposes the same or a different interface to content providers. The exposed API such as by SCEF is not specified in the present document.
The content provider may optionally exchange application level information like service metadata (e.g. serviceIds or URL(s) of USD(s) or other service identifier(s)) directly with the application.
The BM-SC may support CAPIF [10]. When CAPIF is supported, then:
  • the BM-SC shall support the CAPIF API provider domain functions (i.e. CAPIF-2/2e (xMB), CAPIF-3, CAPIF-4 and CAPIF-5 as specified in TS 23.222);
  • the BM-SC xMB authentication and authorization functions (as defined in Clause 5.2) are replaced by CAPIF equivalent core domain functions (i.e. CAPIF-1/1e).
The CAPIF and associated API provider domain functions are specified in TS 23.222.
The content provider may be a mission critical service provider ([12]), which is arranging MC Services to Mission Critical Organizations. Providing MC Services may require additional control of the resource allocation (QoS, coverage area). For this purpose, the interface can be extended with the xMB mission critical extension. The xMB mission critical extension consists in:
  • additional properties within the control plane procedures (Table 5.4-6),
  • specific semantic and syntax for the geographical area (Clause 5.4.7).
The Content Provider may be a 5GMS Application Provider as defined in clause 4.6 of TS 26.501, providing 5G Media Streaming services to a 5GMS System, as shown in Figure 4.1-2. In this case, Content Receiver <APP> includes a 5GMS Client that can be served at least partially by the MBMS Client. The 5GMS Application Function (5GMS AF) invokes xMB-C control plane procedures on the BM-SC as specified in clauses 5.3 and 5.4 and, as a result, content is ingested by the BM-SC from the 5GMS Application Server (5GMS AS) using the xMB-U File Distribution procedures specified in clause 5.5.2 to support delivery of xMB-C Session types Application or Files. Procedures for 5GMS content delivery via eMBMS, including communication of the 5GMS AF and 5GMS AS with the BM-SC are defined in clause 5.10 of TS 26.501.
Copy of original 3GPP image for 3GPP TS 26.348, Fig. 4.1-2: 5GMS over eMBMS
Figure 4.1-2: 5GMS over eMBMS
(⇒ copy of original 3GPP image)

4.2  xMB reference pointp. 9

The xMB reference point exists between the content provider and the BM-SC directly or via 3GPP defined enabler / exposure functions such as SCEF. When the BM-SC connects to content provider via a 3GPP defined enabler / exposure function, the xMB-C interface (and optionally also the xMB-U) is terminated at the 3GPP defined enabler / exposure function.
The xMB reference point provides the ability for the content provider to:
  • authenticate and authorize BM-SC(s).
  • create, modify and terminate a service.
  • create, modify and terminate a session.
  • query information.
  • deliver content to the BM-SC(s)
The xMB reference point provides the ability for the BM-SC to:
  • authenticate and authorize a content provider.
  • notify the content provider of the status of an MBMS user service usage.
  • retrieve content from the content provider.
The xMB reference point shall support security function for confidentiality protection of both control plane (xMB-C) and user plane (xMB-U).

Up   Top   ToC