Liaison statement
CLUE WG response to LS to IETF CLUE WG on media handling aspects related to CLUE protocol

State Posted
Posted Date 2015-03-30
From Group clue
From Contact Roni Even
To Contacts
CcDaniel Burnett
Paul Kyzivat
Roni Even
Ben Campbell
Alissa Cooper
ControLling mUltiple streams for tElepresence Discussion List
Purpose In response
Attachments CLUE Response
Liaisons referred by this one LS to IETF CLUE WG on media handling aspects related to CLUE protocol
1. Overall
3GPP SA4 asked IETF CLUE to inform SA4 on the progress of CLUE work group on any media handling aspects related to CLUE protocol.

2. CLUE status:
It was brought to our attention that many CLUE documents are already endorsed by 3GPP in 3GPP TS 24.103 ( ).

From the attached document (SP-140483_S4-140989 Rel-13_WID IMS_TELEP) we conclude that 3GPP SA4 has an interest in the following aspects and we will try to respond what is the CLUE status for each item

• Media codecs (speech, video, real-time text) for IMS-based telepresence – CLUE does not recommend any specific codecs. The topic is out of scope for CLUE WG.

•Media configuration including session setup and control procedures for IMS-based telepresence, and media provisioning aspects of capability negotiation based on SDP and CLUE protocols, etc. – This is the major focus of the CLUE WG as specified in the WG charter (clue/charter/). The following documents defines these topic:

- Framework for Telepresence Multi-Streams in draft-ietf-clue-framework-21 defines a framework for a protocol to enable devices in a telepresence conference to interoperate. This document is now going to publication which means that the CLUE WG agrees that it is ready
- CLUE signaling in draft-ietf-clue-signaling-05 defines how to use SIP and SDP to establish a Telepresence call. The document is still a work in progress.
- The CLUE protocol is specified in draft-ietf-clue-protocol-03 specifies the negotiation of a CLUE telepresence session. It is using the XML schema for the CLUE data model specified in draft-ietf-clue-data-model-schema-07 . These documents are work in progress but they are quiet mature.

• Set-up and control of the individual media streams between clients including interactivity, such as adding and dropping of media components, as well as end-to-end QoS handling, etc. for IMS-based telepresence. – This is not in the scope of the CLUE WG, the support for set-up and control of individual streams is based on existing tools that were specified by other WGs like AVTcore, AVText, Payload and MMUSIC.
• Data transport including usage of RTP / RTCP protocols, RTP profiles, RTP payload formats, RTP mapping, media synchronization, etc. for IMS-based telepresence, e.g., in relation to negotiation and establishment of the CLUE data channel, and exchange of CLUE ADVERTISEMENT and CONFIGURE messages – This topic is discussed in the CLUE signaling document and some aspects of mapping RTP streams to CLUE Media Captures are discussed in draft-ietf-clue-rtp-mapping-04
• Requirements and guidelines for media adaptation in IMS-based telepresence, for example in response to changes of network bandwidth – this is not in the scope of CLUE work. A general solution for congestion control is discussed in the IETF RMCAT WG.