RFC 3327 (rfc3327) - Page 1 of 17
Session Initiation Protocol (SIP) Extension Header Field for Registering Non-Adjacent Contacts
Alternative Format: Original Text Document
Network Working Group D. Willis
Request for Comments: 3327 dynamicsoft Inc.
Category: Standards Track B. Hoeneisen
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December 2002
Session Initiation Protocol (SIP) Extension Header Field
for Registering Non-Adjacent Contacts
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
The REGISTER function is used in a Session Initiation Protocol (SIP)
system primarily to associate a temporary contact address with an
address-of-record. This contact is generally in the form of a
Uniform Resource Identifier (URI), such as Contact:
[email protected]> and is generally dynamic and associated
with the IP address or hostname of the SIP User Agent (UA). The
problem is that network topology may have one or more SIP proxies
between the UA and the registrar, such that any request traveling
from the user's home network to the registered UA must traverse these
proxies. The REGISTER method does not give us a mechanism to
discover and record this sequence of proxies in the registrar for
future use. This document defines an extension header field, "Path"
which provides such a mechanism.
Willis & Hoeneisen Standards Track