Managing Client-Initiated Connections in the Session Initiation Protocol (SIP)
RFC 5626
Document | Type | RFC - Proposed Standard (October 2009; No errata) | |
---|---|---|---|
Authors | Rohan Mahy , Francois Audet , Cullen Jennings | ||
Last updated | 2015-10-14 | ||
Replaces | draft-jennings-sipping-outbound | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5626 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Robert Sparks | ||
Send notices to | audet@nortel.com |
Network Working Group C. Jennings, Ed. Request for Comments: 5626 Cisco Systems Updates: 3261, 3327 R. Mahy, Ed. Category: Standards Track Unaffiliated F. Audet, Ed. Skype Labs October 2009 Managing Client-Initiated Connections in the Session Initiation Protocol (SIP) Abstract The Session Initiation Protocol (SIP) allows proxy servers to initiate TCP connections or to send asynchronous UDP datagrams to User Agents in order to deliver requests. However, in a large number of real deployments, many practical considerations, such as the existence of firewalls and Network Address Translators (NATs) or the use of TLS with server-provided certificates, prevent servers from connecting to User Agents in this way. This specification defines behaviors for User Agents, registrars, and proxy servers that allow requests to be delivered on existing connections established by the User Agent. It also defines keep-alive behaviors needed to keep NAT bindings open and specifies the usage of multiple connections from the User Agent to its registrar. 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) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of Jennings, et al. Standards Track [Page 1] RFC 5626 Client-Initiated Connections in SIP October 2009 the Trust Legal Provisions and are provided without warranty as described in the BSD License. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 5 2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 5 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Summary of Mechanism . . . . . . . . . . . . . . . . . . . 6 3.2. Single Registrar and UA . . . . . . . . . . . . . . . . . 7 3.3. Multiple Connections from a User Agent . . . . . . . . . . 8 3.4. Edge Proxies . . . . . . . . . . . . . . . . . . . . . . . 10 3.5. Keep-Alive Technique . . . . . . . . . . . . . . . . . . . 11 3.5.1. CRLF Keep-Alive Technique . . . . . . . . . . . . . . 12 3.5.2. STUN Keep-Alive Technique . . . . . . . . . . . . . . 12 4. User Agent Procedures . . . . . . . . . . . . . . . . . . . . 13 4.1. Instance ID Creation . . . . . . . . . . . . . . . . . . . 13 4.2. Registrations . . . . . . . . . . . . . . . . . . . . . . 14 4.2.1. Initial Registrations . . . . . . . . . . . . . . . . 14 4.2.2. Subsequent REGISTER Requests . . . . . . . . . . . . . 16 4.2.3. Third-Party Registrations . . . . . . . . . . . . . . 17 4.3. Sending Non-REGISTER Requests . . . . . . . . . . . . . . 17 4.4. Keep-Alives and Detecting Flow Failure . . . . . . . . . . 18 4.4.1. Keep-Alive with CRLF . . . . . . . . . . . . . . . . . 19 4.4.2. Keep-Alive with STUN . . . . . . . . . . . . . . . . . 21 4.5. Flow Recovery . . . . . . . . . . . . . . . . . . . . . . 21Show full document text