wdiff rfc6993.original rfc6993.txt

Network Working Group
Internet Engineering Task Force (IETF) P. Saint-Andre
Internet-Draft
Request for Comments: 6993 Cisco Systems, Inc.
Intended status:
Category: Informational May 30, 2013
Expires: December 1, July 2013
ISSN: 2070-1721

Instant Messaging and Presence Purpose for the Call-Info Header Field in
the Session Initiation Protocol (SIP)
draft-saintandre-impp-call-info-04

Abstract

This document defines and registers a value of "impp" ("instant
messaging and presence protocol") for the "purpose" header field
parameter of the Call-Info header field in the Session Initiation
Protocol (SIP).

Status of this This Memo

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provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on December 1, 2013.
http://www.rfc-editor.org/info/rfc6993.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2
2. Security Considerations . . . . . . . . . . . . . . . . . . . . 3 2
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3
4.1. Normative References . . . . . . . . . . . . . . . . . . . 4 3
4.2. Informative References . . . . . . . . . . . . . . . . . . 4 3
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5

1. Introduction

To improve interoperability among

Some real-time communication endpoints
that support the combined use of
the Session Initiation Protocol (SIP) [RFC3261] and the Extensible
Messaging and Presence Protocol (XMPP) [RFC6120] (so-called [RFC6120]. To improve
interoperability among such "CUSAX" endpoints [I-D.ivov-xmpp-cusax]), [CUSAX], it can be
helpful to communicate the advertise each endpoint's SIP address over XMPP and the each
endpoint's XMPP address over SIP to provide SIP, thus providing hints about the
endpoints
communication capabilities. capabilities of the endpoints. The former feature is
enabled by an XMPP extension protocol called Reachability Addresses
[XEP-0152]. As to the latter feature, discussion in the SIP
community led to the conclusion that it would be best to use the
Call-Info header field [RFC3261] with a value of "impp" ("instant
messaging and presence protocol") for the "purpose" header field
parameter. An example follows.

Call-Info: <xmpp:juliet@example.com> ;purpose=impp

Although CUSAX endpoints constitute the primary use case for the
"impp" purpose, a Uniform Resource Identifier (URI) [RFC3986] for an
instant messaging and presence protocol other than XMPP could be
included in the Call-Info header field.

2. Security Considerations

Advertising an endpoint's XMPP address over SIP could inform
malicious entities about an alternative attack vector. Because the
"purpose" header field parameter could be spoofed, the receiving
endpoint ought to check the value against an authoritative source
such as a user directory. Clients can integrity protect and encrypt
this header field using end-to-end mechanisms such as S/MIME or hop-
by-hop mechanisms such as TLS. Transport Layer Security (TLS).

This specification provides a new way to correlate otherwise possibly
unconnected identifiers. Because such correlations can be privacy
sensitive, user agents ought to provide a means for users to control
whether or not these values are sent.

3. IANA Considerations

This document defines and registers a new predefined value "impp" for
the "purpose" header field parameter of the Call-Info header field.
The IANA can complete has completed this action by adding this RFC as a reference
to the line for the header field "Call-Info" and parameter name
"purpose" in the Header "Header Field Parameters and Parameter Values Values"
section of the Session "Session Initiation Protocol (SIP) Parameters registry: Parameters"
registry as follows:

Header Field: Call-Info
Parameter Name: purpose
Predefined Values: Yes
Reference: [RFC3261][RFC5367][RFC6910][this document] [RFC3261][RFC5367][RFC6910][RFC6993]

4. References

4.1. Normative References

[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.

[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.

[RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Core", RFC 6120, March 2011.

4.2. Informative References

[I-D.ivov-xmpp-cusax]

[CUSAX] Ivov, E., Saint-Andre, P., and E. Marocco, "Combined "CUSAX:
Combined Use of the Session Initiation Protocol (SIP) and
the Extensible Messaging and Presence Protocol (CUSAX)",
draft-ivov-xmpp-cusax-05 (work (XMPP)",
Work in progress), May Progress, June 2013.

[XEP-0152]
Saint-Andre, P. and J. Hildebrand, "Reachability
Addresses", XSF XEP 0152, February 2013.

Appendix A. Acknowledgements

Thanks to Gonzalo Camarillo, Keith Drage, Saul Ibarra, Emil Ivov,
Cullen Jennings, Olle Johanssen, Paul Kyzivat, Gonzalo Salgueiro,
Dean Willis, and Dale Worley for their input. Elwyn Davies,
Salvatore Loreto, Glen Zorn, and Mehmet Ersue completed reviews on
behalf of the General Area Review Team, Applications Area
Directorate, Security Directorate, and Operations and Management
Directorate, respectively. Stephen Farrell and Pete Resnick provided
substantive feedback during IESG review. Thanks to Yana Stamcheva
for her helpful comments and for shepherding the document.

Author's Address

Peter Saint-Andre
Cisco Systems, Inc.
1899 Wynkoop Street, Suite 600
Denver, CO 80202
USA

Phone: +1-303-308-3282
Email:
EMail: psaintan@cisco.com