A Mechanism for Transporting User-to-User Call Control Information in SIP
RFC 7433
Internet Engineering Task Force (IETF) A. Johnston
Request for Comments: 7433 Avaya
Category: Standards Track J. Rafferty
ISSN: 2070-1721 Human Communications
January 2015
A Mechanism for Transporting User-to-User Call Control Information
in SIP
Abstract
There is a class of applications that benefit from using SIP to
exchange User-to-User Information (UUI) data during session
establishment. This information, known as call control UUI data, is
a small piece of data inserted by an application initiating the
session and utilized by an application accepting the session. The
syntax and semantics for the UUI data used by a specific application
are defined by a UUI package. This UUI data is opaque to SIP and its
function is unrelated to any basic SIP function. This document
defines a new SIP header field, User-to-User, to transport UUI data,
along with an extension mechanism.
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/rfc7433.
Johnston & Rafferty Standards Track [Page 1]
RFC 7433 SIP UUI for CC January 2015
Copyright Notice
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Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements Discussion . . . . . . . . . . . . . . . . . . . 4
4. Normative Definition . . . . . . . . . . . . . . . . . . . . 5
4.1. Syntax for UUI Header Field . . . . . . . . . . . . . . . 6
4.2. Hex Encoding Definition . . . . . . . . . . . . . . . . . 7
4.3. Source Identity of UUI Data . . . . . . . . . . . . . . . 7
5. Guidelines for UUI Packages . . . . . . . . . . . . . . . . . 9
5.1. Extensibility . . . . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. Registration of User-to-User Header Field . . . . . . . . 11
6.2. Registration of User-to-User Header Field Parameters . . 11
6.3. Registration of UUI Packages . . . . . . . . . . . . . . 11
6.4. Registration of UUI Content Parameters . . . . . . . . . 12
6.5. Registration of UUI Encoding Parameters . . . . . . . . . 12
6.6. Registration of SIP Option Tag . . . . . . . . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . 15
Appendix A. Other Possible Mechanisms . . . . . . . . . . . . . 17
A.1. Why INFO is Not Used . . . . . . . . . . . . . . . . . . 17
A.2. Why Other Protocol Encapsulation UUI Mechanisms Are Not
Used . . . . . . . . . . . . . . . . . . . . . . . . . . 17
A.3. MIME Body Approach . . . . . . . . . . . . . . . . . . . 17
A.4. URI Parameter . . . . . . . . . . . . . . . . . . . . . . 18
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
Johnston & Rafferty Standards Track [Page 2]
RFC 7433 SIP UUI for CC January 2015
1. Overview
This document describes the transport of UUI data using SIP
[RFC3261]. It defines a mechanism for the transport of general
application UUI data and for the transport of the call control
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