Network Working Group                                          M. Tuexen
Request for Comments: 5133            Muenster Univ. of Applied Sciences
Updates: 4233                                               K. Morneault
Category: Standards Track                            Cisco Systems, Inc.
                                                           December 2007

     Terminal Endpoint Identifier (TEI) Query Request Number Change

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

   The Integrated Services Digital Network (ISDN) Q.921-User Adaptation
   Layer (IUA) Protocol, described in RFC 4233, defines the message type
   of Terminal Endpoint Identifier (TEI) Query Request messages as 5.
   However, this number is already being used by the Digital Private
   Network Signaling System (DPNSS)/Digital Access Signaling System 2
   (DASS 2) Extensions (DUA) to the IUA Protocol described in RFC 4129.
   This document updates RFC 4233 such that the message type of TEI
   Query Request messages is 8.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  Conventions Used in This Document . . . . . . . . . . . . . . . 2
   3.  New Message Type of the TEI Query Message . . . . . . . . . . . 2
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 2
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 2
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 2
   7.  Normative References  . . . . . . . . . . . . . . . . . . . . . 3

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1.  Introduction

   The Integrated Services Digital Network (ISDN) Q.921-User Adaptation
   Layer (IUA) protocol, described in [RFC3057], does not define a
   Terminal Endpoint Identifier (TEI) Query Request message.  The
   Digital Private Network Signaling System (DPNSS)/Digital Access
   Signaling System 2 (DASS 2) Extensions (DUA) to the IUA Protocol,
   described in [RFC4129], introduces Data Link Connection (DLC) Status
   messages of type 5, 6, and 7.  Then, [RFC4233] was published, which
   updates [RFC3057].  [RFC4233] also introduces the TEI Query Request
   message and uses the message type of 5 for it.  This makes it
   impossible to differentiate the DLC Status request from a TEI Query
   Request.

   This document updates [RFC4233].

2.  Conventions Used in This Document

   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].

3.  New Message Type of the TEI Query Message

   This document updates [RFC4233] by introducing the following change:

   Terminal Endpoint Identifier (TEI) Query messages MUST be encoded
   with a message type of 8 instead of 5 as described in [RFC4233].

4.  IANA Considerations

   In the "Message Types" section of the "Signaling User Adaptation
   Layer Assignments" registry, IANA has reserved the message type 8 of
   Management Messages for Terminal Endpoint Identifier (TEI) Query
   Request messages.

5.  Security Considerations

   This document does not require any security considerations in
   addition to the ones given in [RFC4233].

6.  Acknowledgments

   The authors wish to thank Jon Peterson and Christian Vogt for their
   invaluable comments.

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RFC 5133            TEI Query Request Number Change        December 2007

7.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3057]  Morneault, K., Rengasami, S., Kalla, M., and G.
              Sidebottom, "ISDN Q.921-User Adaptation Layer", RFC 3057,
              February 2001.

   [RFC4129]  Mukundan, R., Morneault, K., and N. Mangalpally, "Digital
              Private Network Signaling System (DPNSS)/Digital Access
              Signaling System 2 (DASS 2) Extensions to the IUA
              Protocol", RFC 4129, September 2005.

   [RFC4233]  Morneault, K., Rengasami, S., Kalla, M., and G.
              Sidebottom, "Integrated Services Digital Network (ISDN)
              Q.921-User Adaptation Layer", RFC 4233, January 2006.

Authors' Addresses

   Michael Tuexen
   Muenster Univ. of Applied Sciences
   Stegerwaldstr. 39
   48565 Steinfurt
   Germany

   EMail: tuexen@fh-muenster.de

   Ken Morneault
   Cisco Systems, Inc.
   13615 Dulles Technology Drive
   Herndon, VA  20171
   US

   Phone: +1-703-484-3323
   EMail: kmorneau@cisco.com

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RFC 5133            TEI Query Request Number Change        December 2007

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