Representing Trunk Groups in tel/sip Uniform Resource Identifiers (URIs)
RFC 4904

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>, 
    iptel mailing list <iptel@ietf.org>, 
    iptel chair <iptel-chairs@tools.ietf.org>
Subject: Protocol Action: 'Representing trunk groups in tel/sip 
         Uniform Resource Identifiers (URIs)' to Proposed Standard 

The IESG has approved the following document:

- 'Representing trunk groups in tel/sip Uniform Resource Identifiers 
   (URIs) '
   <draft-ietf-iptel-trunk-group-11.txt> as a Proposed Standard

This document is the product of the IP Telephony Working Group. 

The IESG contact persons are Jon Peterson and Cullen Jennings.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-iptel-trunk-group-11.txt

Technical Summary
 
The trunk group extension to the tel URI defines two new URI parameters
for use with the tel URI (defined in RFC 3966). These two new URI
parameters, "tgrp" and "trunk-context" indicate the name and namespace
scope for a trunk group. A trunk group is a collection of circuits in the
Public Switched Telephone Network (PSTN) which are managed as a group. One
trunk group, for example, can be used for toll free calls, while another
one used for calls to a certain carrier, and another for calls to a
certain local calling area. Consequently, when connecting calls from the
PSTN into a VoIP network, and connecting calls from a VoIP network into
the PSTN, it is necessary to convey trunk group information in the VoIP
domain. For example, a SIP proxy may route a call towards a PSTN gateway,
and need to indicate that a specific trunk group should be used. As
another example, a call from a PSTN gateway towards a SIP proxy might need
to indicate that the call arrived from a specific trunk group, so that the
SIP proxy might make appropriate call routing decisions.

The specification defines the syntax for these parameters, matching
rules, and usage of them with SIP.
 
Working Group Summary
 
The draft is a charter item of the IP Telephony (iptel) working group, and
is targeted for Proposed Standard. It was adopted as a working group item
in early 2003 and discussed on the mailing list and in many meetings since
its adoption.
 
Protocol Quality
 
The specification has been implemented in many products and there areknown
deployments of it. The specification itself has received reviews from
telephony experts as well as SIP experts. This document was reviewed for
the IESG by Jon Peterson.