datatracker.ietf.org
Sign in
Version 5.12.0, 2015-02-26
Report a bug

The Integrated Services Digital Network (ISDN) Subaddress Encoding Type for tel URI
RFC 4715

Document type: RFC - Informational (November 2006; No errata)
Was draft-munakata-iptel-isub-type (individual in rai area)
Document stream: IETF
Last updated: 2013-03-02
Other versions: plain text, pdf, html

IETF State: (None)
Consensus: Unknown
Document shepherd: No shepherd assigned

IESG State: RFC 4715 (Informational)
Responsible AD: Cullen Jennings
Send notices to: munakata.mayumi@lab.ntt.co.jp, shida@ntt-at.com, ohba.takumi@lab.ntt.co.jp

Network Working Group                                        M. Munakata
Request for Comments: 4715                                   S. Schubert
Category: Informational                                          T. Ohba
                                                                     NTT
                                                           November 2006

            The Integrated Services Digital Network (ISDN)
                  Subaddress Encoding Type for tel URI

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2006).

Abstract

   Without a tel URI parameter to carry an encoding type of Integrated
   Services Digital Network (ISDN) subaddress, interworking between ISDN
   User Part (ISUP) network and a Session Initiation Protocol (SIP)
   network is impossible in some cases.  To solve this problem, this
   document specifies a new optional tel URI parameter to carry the
   encoding type of ISDN subaddress.

Munakata, et al.             Informational                      [Page 1]
RFC 4715                    ISDN for tel URI               November 2006

Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................3
   3. Problem Statement ...............................................3
      3.1. SIP-ISDN Interconnection ...................................3
      3.2. ISDN-SIP-ISDN Interconnection ..............................4
   4. Requirements ....................................................5
   5. Parameter Definition ............................................6
   6. Usage ...........................................................6
      6.1. Gateway Behavior ...........................................7
      6.2. SIP Entity Behavior ........................................8
   7. Security Considerations .........................................9
   8. IANA Considerations .............................................9
   9. Acknowledgements ................................................9
   10. References ....................................................12
      10.1. Normative References .....................................12
      10.2. Informative References ...................................12

1.  Introduction

   RFC 3966 [2] defines a tel URI parameter "isub" that is designed to
   carry Integrated Services Digital Network (ISDN) subaddresses.

   In an ISDN User Part (ISUP) message, a Network Service Access Point
   (NSAP) address [6] or a "user specified" address can be carried as an
   ISDN subaddress.  The NSAP address accommodates various types of
   address information along with an identifier for the address type and
   its encoding type.

   The "isub" parameter can carry any type of address, but RFC 3966 [2]
   does not define a solution to carry information on a subaddress type
   (whether the subaddress is NSAP or user specific) or an identifier
   for the encoding type used.

   The most commonly used encoding type for the ISDN subaddress is an
   International Alphabet 5 (IA5) [5].  RFC 3966 does state, "ISDN
   subaddresses typically contain IA5 characters but may contain any
   octet value" considering this fact.  Nevertheless, IA5 is just one of
   the encoding types among various encoding types used in the NSAP
   address.  Therefore, "isub" parameter alone is not sufficient to
   describe ISDN subaddresses, and additional information is needed.

Munakata, et al.             Informational                      [Page 2]
RFC 4715                    ISDN for tel URI               November 2006

      Lack of information describing the encoding type of ISDN
      subaddress will make it difficult for an ISDN terminal receiving
      the ISDN subaddress from the SIP network (SIP-ISDN
      Interconnection) to interpret the "isub" parameter value, as a
      gateway may translate it using a wrong encoding type and end up
      with a wrong subaddress value due to inconsistency in the encoding
      type used.  It will also make it difficult to recover the original
      ISDN subaddress value when an ISUP message is translated to a SIP
      message and translated back to the ISUP message (ISDN-SIP-ISDN
      Interconnection).  As there is no placeholder to carry the
      encoding type in the SIP message, the encoding type information
      that was present in the original ISUP message will be lost, and
      reconstructing the intended ISDN subaddress value is nearly
      impossible.

   To solve the issues presented, this specification defines an "isub-

[include full document text]