RFC 3515 (rfc3515) - Page 1 of 23
The Session Initiation Protocol (SIP) Refer Method
Alternative Format: Original Text Document
Network Working Group R. Sparks
Request for Comments: 3515 dynamicsoft
Category: Standards Track April 2003
The Session Initiation Protocol (SIP) Refer Method
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 (2003). All Rights Reserved.
Abstract
This document defines the REFER method. This Session Initiation
Protocol (SIP) extension requests that the recipient REFER to a
resource provided in the request. It provides a mechanism allowing
the party sending the REFER to be notified of the outcome of the
referenced request. This can be used to enable many applications,
including call transfer.
In addition to the REFER method, this document defines the the refer
event package and the Refer-To request header.
Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. The REFER Method . . . . . . . . . . . . . . . . . . . . . . 3
2.1 The Refer-To Header Field . . . . . . . . . . . . . . . 3
2.2 Header Field Support for the REFER Method . . . . . . . 4
2.3 Message Body Inclusion. . . . . . . . . . . . . . . . . 5
2.4 Behavior of SIP User Agents . . . . . . . . . . . . . . 6
2.4.1 Forming a REFER request . . . . . . . . . . . . . 6
2.4.2 Processing a REFER request. . . . . . . . . . . . 6
2.4.3 Accessing the Referred-to Resource. . . . . . . . 6
2.4.4 Using SIP Events to Report the Results
of the Reference. . . . . . . . . . . . . . . . . 7
2.4.5 The Body of the NOTIFY. . . . . . . . . . . . . . 8
2.4.6 Multiple REFER Requests in a Dialog . . . . . . . 9
2.4.7 Using the Subscription-State Header
Field with Event Refer. . . . . . . . . . . . . . 9
Sparks Standards Track