Indicating Fax over IP Capability in the Session Initiation Protocol (SIP)
draft-hanes-dispatch-fax-capability-03

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Last updated 2012-10-08
Stream (None)
Intended RFC status (None)
Formats plain text pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
DISPATCH                                                        D. Hanes
Internet-Draft                                              G. Salgueiro
Intended status: Standards Track                           Cisco Systems
Expires: April 11, 2013                                       K. Fleming
                                                            Digium, Inc.
                                                         October 8, 2012

                   Indicating Fax over IP Capability
                in the Session Initiation Protocol (SIP)
                 draft-hanes-dispatch-fax-capability-03

Abstract

   This document defines and registers with IANA the new 'fax' media
   feature tag for use with SIP.  Currently, fax calls are
   indistinguishable from voice at call setup.  Consequently, fax calls
   can be routed to SIP user agents that are not fax capable.  A 'fax'
   media feature tag implemented in conjunction with RFC 3841 [RFC3841]
   allows for more accurate fax call routing.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 11, 2013.

Copyright Notice

   Copyright (c) 2012 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

Hanes, et al.            Expires April 11, 2013                 [Page 1]
Internet-Draft            Fax Media Feature Tag             October 2012

   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8

Hanes, et al.            Expires April 11, 2013                 [Page 2]
Internet-Draft            Fax Media Feature Tag             October 2012

1.  Introduction

   Fax communications in the Session Initiation Protocol (SIP) are
   handled in a "voice first" manner.  Indications that a user desires
   to use a fax transport protocol, such as ITU-T T.38[T38], to send a
   fax are not known during the call setup.  The call is set up as a
   voice call first and then only after it is connected, does a
   switchover to the T.38[T38] protocol occur.  This is problematic in
   that fax calls can be routed inadvertently to SIP user agents that
   are not fax capable.

   To ensure that fax calls are routed to fax capable SIP user agents,
   an implementation of caller preferences defined in RFC 3841 [RFC3841]
   is necessary.  Feature preferences are a part of RFC 3841 [RFC3841]
   that would allow UAs to express their preference for receiving fax
   communications.  Subsequently SIP servers take these preferences into
   account to increase the likelihood that fax calls land at fax capable
   SIP user agents.

   This document defines the 'fax' media feature tag for use in the SIP
   tree as per Section 12.1 of RFC 3840 [RFC3840].  This feature tag
   will be applied per RFC 3841 [RFC3841] as a feature preference for
   fax capable UAs.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].
Show full document text