Network Working Group J. Rosenberg
Request for Comments: 3262 dynamicsoft
Category: Standards Track H. Schulzrinne
Columbia U.
June 2002
Reliability of Provisional Responses
in the Session Initiation Protocol (SIP)
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
This document specifies an extension to the Session Initiation
Protocol (SIP) providing reliable provisional response messages.
This extension uses the option tag 100rel and defines the Provisional
Response ACKnowledgement (PRACK) method.
Table of Contents
1 Introduction ........................................ 2
2 Terminology ......................................... 3
3 UAS Behavior ........................................ 3
4 UAC Behavior ........................................ 6
5 The Offer/Answer Model and PRACK .................... 9
6 Definition of the PRACK Method ...................... 10
7 Header Field Definitions ............................ 10
7.1 RSeq ................................................ 10
7.2 RAck ................................................ 11
8 IANA Considerations ................................. 11
8.1 IANA Registration of the 100rel Option Tag .......... 11
8.2 IANA Registration of RSeq and RAck Headers .......... 12
9 Security Considerations ............................. 12
10 Collected BNF ....................................... 12
11 Acknowledgements .................................... 12
12 Normative References ................................ 13
13 Informative References .............................. 13
Rosenberg & Schulzrinne Standards Track