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Liaison statement
Comments on IETF PhoneBCP Draft

State Posted
Submitted Date 2009-09-15
From Group 3GPP
From Contact Susanna Kooistra
To Group IETF
To Contacts
Purpose For action
Deadline 2009-11-20 Action Taken
Attachments (None)
3GPP TSG SA WG2 Meeting #75                     S2-096100
31 August – 4 September, 2009, Kyoto, Japan

Title:  Comments on IETF PhoneBCP Draft

Source: 3GPP TSG SA WG2
To:     Hannes Tschofenig (, Chairman IETF Ecrit
        Marc Linsner (, Chairman IETF Ecrit
        Cullen Jennings (, IETF Real-time Applications and
        Infrastructure Area Director
Cc:     IETF Ecrit Working Group
        3GPP TSG CT WG1
        3GPP TSG SA WG1

Contact Person:
Name:   Stephen Edge
Tel. Number:    +1-858-651-6234
E-mail Address:

Attachments:    None

1. Overall Description:
3GPP TSG SA WG2 along with 3GPP TSG CT WG1 were requested by the TSG CT Chair
on behalf of IETF Ecrit on May 6 to provide feedback on the issue of
applicability of the phoneBCP draft to a cellular environment.

The Email request was as follows:

From: Hannu Hietalahti [mailto:hannu.hietalahti@NOKIA.COM]
Sent: Wednesday, May 06, 2009 4:48 AM
Subject: Question on draft-ietf-ecrit-phonebcp

Dear CT1, SA2,

in the 3GPP - IETF telco earlier this week a question was brought up on whether
the phonebcp IETF draft could be applicable on cellular systems or not:

We have got no dependency from 3GPP specifications and I am not saying that we
should have. In the 3GPP - IETF telco I promised to ping the 3GPP groups
working in the area of VoIP and emergency calls just in case someone might be
able to help in this question.

The question seems to be whether it would be justified or not to restrict the
applicability area of the draft by excluding the use of it in cellular
environment. Even if we are currenlty not directly referencing to the draft,
for me it sounds a bit odd if IETF needs to start categorising SIP extensions
to those that are applicable in cellular environment and to those that are not.

If you think you can help to solve this, please keep the CC'd Cullen Jennings
and Hannes Tschofenig in the discussion.

Hannu Hietalahti
3GPP TSG CT Chairman
tel: +358 40 5021724

3GPP SA WG2 discussed the issue of applicability as well as interworking
between the solution to support IP based emergency calls defined in the Ecrit
phoneBCP draft and the solution defined by 3GPP in 3GPP TS 23.167. The
consensus in SA2 is that these issues need further evaluation including an
analysis of regulator requirements (e.g. by 3GPP SA1) to determine whether and
how the Ecrit solution could apply to 3GPP networks. A suitable applicability
statement to include in the phoneBCP draft, assuming it is intended to apply to
any cellular network, would thus be "the applicability of this solution to 3GPP
wireless networks requires further evaluation in 3GPP".

2. Actions:
To IETF Ecrit group.
ACTION:  3GPP SA2 requests IETF Ecrit to take the above comments and
recommendation into account when finalizing the phoneBCP draft.

3. Date of Next TSG-SA WG2 Meetings:
TSG-SA2 Meeting #76     16th – 20th November 2009       San Jose Del Cabo,
Mexico TSG-SA2 Meeting #77     18th – 22nd January 2010        China