The WebSocket Protocol as a Transport for the Session Initiation Protocol (SIP)
RFC 7118

Internet Engineering Task Force (IETF)                   I. Baz Castillo
Request for Comments: 7118                            J. Millan Villegas
Category: Standards Track                                      Versatica
ISSN: 2070-1721                                               V. Pascual
                                                                  Quobis
                                                            January 2014

             The WebSocket Protocol as a Transport for the
                   Session Initiation Protocol (SIP)

Abstract

   The WebSocket protocol enables two-way real-time communication
   between clients and servers in web-based applications.  This document
   specifies a WebSocket subprotocol as a reliable transport mechanism
   between Session Initiation Protocol (SIP) entities to enable use of
   SIP in web-oriented deployments.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7118.

Copyright Notice

   Copyright (c) 2014 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Baz Castillo, et al.         Standards Track                    [Page 1]
RFC 7118            WebSocket as a Transport for SIP        January 2014

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  The WebSocket Protocol  . . . . . . . . . . . . . . . . . . .   3
   4.  The WebSocket SIP Subprotocol . . . . . . . . . . . . . . . .   4
     4.1.  Handshake . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  SIP Encoding  . . . . . . . . . . . . . . . . . . . . . .   5
   5.  SIP WebSocket Transport . . . . . . . . . . . . . . . . . . .   6
     5.1.  Via Transport Parameter . . . . . . . . . . . . . . . . .   6
     5.2.  SIP URI Transport Parameter . . . . . . . . . . . . . . .   6
     5.3.  Via "received" Parameter  . . . . . . . . . . . . . . . .   7
     5.4.  SIP Transport Implementation Requirements . . . . . . . .   7
     5.5.  Locating a SIP Server . . . . . . . . . . . . . . . . . .   8
   6.  Connection Keep-Alive . . . . . . . . . . . . . . . . . . . .   8
   7.  Authentication  . . . . . . . . . . . . . . . . . . . . . . .   8
   8.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Registration  . . . . . . . . . . . . . . . . . . . . . .  10
     8.2.  INVITE Dialog through a Proxy . . . . . . . . . . . . . .  12
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  16
     9.1.  Secure WebSocket Connection . . . . . . . . . . . . . . .  16
     9.2.  Usage of "sips" Scheme  . . . . . . . . . . . . . . . . .  16
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
     10.1.  Registration of the WebSocket SIP Subprotocol  . . . . .  16
     10.2.  Registration of New NAPTR Service Field Values . . . . .  17
     10.3.  SIP/SIPS URI Parameters Subregistry  . . . . . . . . . .  17
     10.4.  Header Fields Subregistry  . . . . . . . . . . . . . . .  17
     10.5.  Header Field Parameters and Parameter Values Subregistry  17
     10.6.  SIP Transport Subregistry  . . . . . . . . . . . . . . .  18
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  18
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  18
     12.2.  Informative References . . . . . . . . . . . . . . . . .  19
   Appendix A.  Authentication Use Cases . . . . . . . . . . . . . .  21
     A.1.  Just SIP Authentication . . . . . . . . . . . . . . . . .  21
     A.2.  Just Web Authentication . . . . . . . . . . . . . . . . .  21