The Session Initiation Protocol (SIP) Refer Method
RFC 3515
Document | Type |
RFC - Proposed Standard
(April 2003; Errata)
Was draft-ietf-sip-refer (sip WG)
|
|
---|---|---|---|
Author | Robert Sparks | ||
Last updated | 2016-03-31 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3515 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Allison Mankin | ||
IESG note | Approved in 2002-12-12 IESG meeting with just some fixes needed that Bert pointed out and that will be fixed with RFC Editor note: time to stop using atlanta.com etc in favor of RFC 2606 example domains and need for boilerplate. Chairs/author notified, they to let WG know. RFC Editor Note given to Secretariat in hopes of announcement on 13 Dec. [Note from Allison 2002-12-13] | ||
Send notices to | <rohan@cisco.com> |
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 [Page 1] RFC 3515 The SIP Refer Method April 2003 2.5 Behavior of SIP Registrars/Redirect Servers . . . . . . 9 2.6 Behavior of SIP Proxies . . . . . . . . . . . . . . . . 10 3. Package Details: Event refer . . . . . . . . . . . . . . . . 10 3.1 Event Package Name. . . . . . . . . . . . . . . . . . . 10 3.2 Event Package Parameters. . . . . . . . . . . . . . . . 10 3.3 SUBSCRIBE Bodies. . . . . . . . . . . . . . . . . . . . 10 3.4 Subscription Duration . . . . . . . . . . . . . . . . . 10 3.5 NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . 11 3.6 Notifier processing of SUBSCRIBE requests . . . . . . . 11 3.7 Notifier Generation of NOTIFY Requests. . . . . . . . . 11 3.8 Subscriber Processing of NOTIFY Requests. . . . . . . . 11 3.9 Handling of Forked Requests . . . . . . . . . . . . . . 11 3.10 Rate of Notifications . . . . . . . . . . . . . . . . . 11 3.11 State Agents. . . . . . . . . . . . . . . . . . . . . . 11 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.1 Prototypical REFER callflow . . . . . . . . . . . . . . 12 4.2 Multiple REFERs in a dialog . . . . . . . . . . . . . . 14 5. Security Considerations . . . . . . . . . . . . . . . . . . 16 5.1 Constructing a Refer-To URI . . . . . . . . . . . . . . 16 5.2 Authorization Considerations for REFER. . . . . . . . . 17 5.3 Considerations for the use of message/sipfrag . . . . . 18 5.3.1 Circumventing Privacy . . . . . . . . . . . . . . 18 5.3.2 Circumventing Confidentiality . . . . . . . . . . 19 5.3.3 Limiting the Breach . . . . . . . . . . . . . . . 19 5.3.4 Cut, Paste and Replay Considerations. . . . . . . 19 6. Historic Material . . . . . . . . . . . . . . . . . . . . . 20 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . 20 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 21 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 21 9.1 Normative References. . . . . . . . . . . . . . . . . . 21 9.2 Informative References. . . . . . . . . . . . . . . . . 21 10. Intellectual Property Statement. . . . . . . . . . . . . . . 21 11. Author's Address . . . . . . . . . . . . . . . . . . . . . . 22 12. Full Copyright Statement . . . . . . . . . . . . . . . . . . 23 1. Overview This document defines the REFER method. This SIP [1] extension requests that the recipient REFER to a resource provided in theShow full document text