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Liaison Statement: LS out Reply to "Reply LS to 3GPP TSG CT4 on support of ECN"

Submission Date: 2011-03-17
From: 3GPP (Susanna Kooistra)
To: (
Response Contact:
Technical Contact:
Purpose: For information
Attachments: Change request
3GPP TSG CT4 Meeting #52	C4-111025
Salt Lake City, US
21st  – 25th February 2011

Title:	LS out Reply to "Reply LS to 3GPP TSG CT4 on support of ECN"
Response to:	LS (C4-110519, COM 16 – LS 203 – E) on Reply LS to 3GPP
TSG CT4 on support of ECN from ITU-T Q3/16
Release:	Rel-10

Source:	3GPP TSG CT4
To:	ITU-T Q3/16

Contact Person:	
Name:	Phil Hodges
Tel. Number:	+61 404069546
E-mail Address:	Philip . hodges @ Ericsson . com

Attachments:	C4-111026

1. Overall Description:
CT4 thanks ITU-T Q3/16 for their reply liaison regarding Explicit
Congestion Notification support in H.248 and is pleased to read that a
new WI has been initiated to develop a solution that can be used by

CT4 has agreed a stage 3 solution which aims to satisfy the
requirements in 3GPP Rel-10 but it is envisaged that some additional
work will be required to support interworking to non-3GPP ECN

The attached CR includes the stage 3 solution embodied in two packages
described in Annexes. CT4 is aware that the CR contains a number of
errors which will be corrected in a later revision. The CR was agreed
by majority in order to progress the work but it was not agreed by
consensus as it was questioned whether the solution should be a single
H.248 package or as proposed: a generic package and an additional 3GPP
specific package. What is agreed by consensus is that a single ECN
solution (whether it consists of multiple packages or not) is desired
by 3GPP. Hence despite proposing the second package as a 3GPP package
CT4 prefer this being part of a generic ITU-T solution.

CT4 asks ITU-T Q3/16 if the solution described in 3GPP Annexes can be
developed as a single generic solution, i.e. if the scenarios required
by 3GPP can be solved by the generic package(s) and still support all
other scenarios.

2. Actions:
To ITU-T Q3/16 group.
ACTION: 	CT4 kindly asks ITU-T Q3/16 to consider the CT4 agreed stage 3
solution as input to their generic work on H.248.ECN, consider the
above question and provide CT4 with any output drafts on this work from

3. Date of Next CT4 Meetings:

CT4#53	9th – 13th May 2011		Tallinn, Estonia 
CT4#54	22nd – 26th August 2011		Malta