The SIP Supported Header

Document Type Expired Internet-Draft (sip WG)
Authors Jonathan Rosenberg  , Henning Schulzrinne 
Last updated 2001-07-24
Stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Expired & archived
pdf htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The Session Initiation Protocol (SIP) provides a mechanism that allows a client to request that a particular protocol extension be used to process the request. The server declines the request if it does not support the extension. However, there is currently no way for a server to determine which extensions are supported by the client. Knowing about client-supported extensions allows the server to tailor its response accordingly. Furthermore, SIP does not define a way for a client to query a server about the extensions it supports. This document defines a SIP extension that allows clients to indicate, in a request, the set of extensions supported. We also define a mechanism that allows clients, through an OPTIONS request, to determine the extensions supported by a server.


Jonathan Rosenberg (
Henning Schulzrinne (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)