Technical Committee

Addressing Addendum to 
ATM User-Network Interface 
(UNI) Signalling 
Specification Version 4.0 

AF-CS-0107.000


February, 1999

© 1999 by The ATM Forum.  This specification/document may be reproduced and distributed in whole, but 
(except as provided in the next sentence) not in part, for internal and informational use only and not for 
commercial distribution.  Notwithstanding the foregoing sentence, any protocol implementation 
conformance statements (PICS) or implementation conformance statements (ICS) contained in this 
specification/document may be separately reproduced and distributed provided that it is reproduced and 
distributed in whole, but not in part, for uses other than commercial distribution.  All other rights reserved.  
Except as expressly stated in this notice, no part of this specification/document may be reproduced or 
transmitted in any form or by any means, or stored in any information storage and retrieval system, without 
the prior written permission of The ATM Forum.

The information in this publication is believed to be accurate as of its publication date.  Such information is 
subject to change without notice and The ATM Forum is not responsible for any errors.  The ATM Forum 
does not assume any responsibility to update or correct any information in this publication.  
Notwithstanding anything to the contrary, neither The ATM Forum nor the publisher make any 
representation or warranty, expressed or implied, concerning the completeness, accuracy, or applicability of 
any information contained in this publication.  No liability of any kind shall be assumed by The ATM 
Forum or the publisher as a result of reliance upon any information contained in this publication.

The receipt or any use of this document or its contents does not in any way create by implication or 
otherwise:

¥	Any express or implied license or right to or under any ATM Forum member company's patent, 
copyright, trademark or trade secret rights which are or may be associated with the ideas, techniques, 
concepts or expressions contained herein; nor
¥	Any warranty or representation that any ATM Forum member companies will announce any product(s) 
and/or service(s) related thereto, or if such announcements are made, that such  announced product(s) 
and/or service(s) embody any or all of the ideas, technologies, or  concepts contained herein; nor
¥	Any form of relationship between any ATM Forum member companies and the recipient or user of this 
document.

Implementation or use of specific ATM standards or recommendations and ATM Forum specifications will 
be voluntary, and no company shall agree or be obliged to implement them by virtue of participation in The 
ATM Forum.

The ATM Forum is a non-profit international organization accelerating industry cooperation on ATM 
technology.  The ATM Forum does not, expressly or otherwise, endorse or promote any specific products or 
services.

NOTE:  The user's attention is called to the possibility that implementation of the ATM interoperability 
specification contained herein may require use of an invention covered by patent rights held by ATM Forum 
Member companies or others.  By publication of this ATM interoperability specification, no position is 
taken by The ATM Forum with respect to validity of any patent claims or of any patent rights related 
thereto or the ability to obtain the license to use such rights.  ATM Forum Member companies agree to 
grant licenses under the relevant patents they own on reasonable and nondiscriminatory terms and conditions 
to applicants desiring to obtain such a license.  For additional information contact:

The ATM Forum
Worldwide Headquarters
2570 West El Camino Real, Suite 304
Mountain View, CA 94040-1313
Tel:	+1-650-949-6700
Fax:	+1-650-949-6705

Table of Contents
1. INTRODUCTION	1
2. NORMATIVE ADDRESS REFERENCES FOR UNI SIGNALLING 4.0	2
3. USE OF ADDRESSING INFORMATION ELEMENTS	3
3.1 UNI SIGNALLING 4.0 RESTRICTION	3
3.2 NEW PROCEDURES	3
4. REFERENCES	4

1. Introduction
This document is an Addendum to the UNI Signalling 4.0 specification (af-sig-0061.000 [1]). This 
document does not replace af-sig-0061.000 and must be used in conjunction with af-sig-0061.000.  With 
two exceptions (items two and three below), there are no changes to UNI Signalling 4.0 behaviour.  This 
Addendum serves three purposes:
1. It points to the ATM Forum Addressing: Reference Guide [2] which consolidates 
addressing related information from UNI Signaling 4.0 [1] and other ATM Forum 
specifications and which is now the normative source of this information.
2. It allows support of AESAs other than ICD, DCC and E.164.
3. It removes a restriction present in UNI Signalling 4.0.  The new rules which allow the 
removal of this restriction are detailed in Section 3.
This Addendum and the Addressing Reference Guide both use the term AESA (ATM Endsystem Address) 
in place of the term Òprivate ATM addressÓ used in UNI Signalling 4.0.
2. Normative Address References for UNI Signalling 4.0
[NORMATIVE]
The disposition of addressing-related sections of UNI Signalling 4.0 is listed below. 
UNI Signalling 4.0 Section 3.1 is superseded by Addressing Reference Guide Section 4.
UNI 4.0 Section 3.2 remains normative .  Replace the text Ò(all 3 formats, as defined in section 3.1)Ó from 
bullet 2 of UNI Signalling 4.0 Section 3.2 with Òas defined in the Addressing Reference Guide [2] Section 
4Ó.
UNI Signalling 4.0 Section 7.1 is superseded by Addressing Reference Guide Section 4.3.
UNI Signalling 4.0 Annex 1 is superseded by Section 3 of this Addendum.
First paragraph of UNI Signalling 4.0 Annex 5 is superseded by Addressing Reference Guide Section 4.3.
UNI Signalling 4.0 Annex 5.1 is superseded by Addressing Reference Guide Section 4.3.1 and Annex A.
UNI Signalling 4.0 Annex 5.2 is superseded by Addressing Reference Guide Section 4.3.2.
UNI Signalling 4.0 Annex 5.3 is superseded by Addressing Reference Guide Section 8.3 and Annex B.
In UNI Signalling 4.0 Annex 6, replace the reference to Annex 5 with Addressing Reference Guide Annex 
B.

3. Use of Addressing Information Elements
3.1 UNI Signalling 4.0 Restriction
[INFORMATIVE]
Annex 1: Guidelines for Use of ATM Address Formats of UNI Signalling 4.0 (af-sig-0061.000 [1]) imposes 
the restriction that the Called party subaddress information element can only contain an AESA if the Called 
party number information element contains a Native E.164 address.   The use of this combination of 
addresses was intended to allow a private network to tunnel an AESA through a public network which 
supports only Native E.164 addresses.  However, this combination does not support the situation where a 
private network wishes to tunnel an AESA through a public network which supports AESA.
This Addendum removes this restriction and allows the Called party subaddress information element to 
contain an AESA when the Called party number information element also contains an AESA.  This change 
applies to both the Public and Private UNI.
3.2 New Procedures
[NORMATIVE]
This section  supersedes Annex 1: Guidelines for Use of ATM Address Formats in UNI Signalling 4.0 af-
sig-0061.000 [1].  
The Addressing Reference Guide [2] contains general guidelines on the use and allocation of addresses.
Listed below are the rules for the use of various address types in the address information elements supported 
at the Public and Private UNI.
1.  At the Private UNI, only the AESA address format shall be carried in the Called party number 
information element.
2.  The AESA format uses:
_ Type of Number and Addressing/Numbering Plan Identification of ÒUnknown/ATM 
Endsystem AddressÓ when conveyed via Called party number and Calling party number 
information elements, and 
_ Type of Address as ÒATM endsystem addressÓ when conveyed via Called party subaddress 
or Calling party subaddress information elements.
3.  The maximum number of instances of the Called party subaddress information element containing 
an address other than an AESA (e.g. NSAP) is one.
4.  The maximum number of instances of the Called party subaddress information element containing 
an AESA is one.
5.  Other than the number of instances, there is no restriction on when a Called party subaddress 
information element can contain an AESA.
4. References
[1]	"ATM User-Network Interface (UNI) Signalling Specification Version 4.0", The ATM 
Forum Technical Committee, af-sig-0061.000
[2]	ÒATM Forum Addressing: Reference Guide version 1.0Ó, ATM Forum Technical 
Committee, af-ra-0106.000.

Addressing Addendum to UNI4.0		af-cs-0107.000

Page 4 of 4		 The ATM Forum Technical Committee


iii

		
af-cs-0107.000		Addressing Addendum to UNI4.0
Page 3 of 4
The ATM Forum Technical Committee
af-cs-0107.000		 Addressing Addendum to UNI4.0

	iv
Page iv of 4
The ATM Forum Technical Committee