ISO/IEC 9594-3:2020/Amd 1:2025

International
Standard
ISO/IEC 9594-3
Ninth edition
Information technology — Open
2020-11
systems interconnection —
AMENDMENT 1
Part 3:
2025-05
The Directory: Abstract service
definition
AMENDMENT 1: Miscellaneous
enhancements
Reference number
ISO/IEC 9594-3:2020/Amd. 1:2025(en) © ISO/IEC 2025

ISO/IEC 9594-3:2020/Amd. 1:2025(en)
© ISO/IEC 2025
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ISO/IEC 9594-3:2020/Amd. 1:2025(en)
Foreword
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see www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by ITU-T as ITU-T X.511 (2019) Amd. 1 (10/2024) and drafted in
accordance with its editorial rules, in collaboration with Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 6, Telecommunications and information exchange between
systems.
A list of all parts in the ISO/IEC 9594 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body.
A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
Rec. ITU-T X.511 (2019) Amd. 1 (10/2024)
© ISO/IEC 2025 – All rights reserved
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ISO/IEC 9594-3:2020/Amd. 1:2025(en)
INTERNATIONAL STANDARD ISO/IEC 9594-3
RECOMMENDATION ITU-T X.511
Information technology – Open Systems Interconnection – The Directory:
Abstract service definition
Amendment 1
Miscellaneous enhancements
Summary
Amendment 1 to Recommendation ITU-T X.511 (2019) | International Standard ISO/IEC 9594-3:2020 introduces text
updates to facilitate separation between cybersecurity ASN.1 modules and directory ASN.1 modules.

History
Edition Recommendation Approval Study Group Unique ID
1.0 ITU-T X.511 1988-11-25 11.1002/1000/3003
2.0 ITU-T X.511 1993-11-16 7 11.1002/1000/3004
3.0 ITU-T X.511 1997-08-09 7 11.1002/1000/4124
3.1   ITU-T X.511 (1997) Technical Cor. 1 2000-03-31 7 11.1002/1000/5036
3.2   ITU-T X.511 (1997) Amd. 1 2000-03-31 7 11.1002/1000/5035
3.3   ITU-T X.511 (1997) Technical Cor. 2 2001-02-02 7 11.1002/1000/5313
3.4   ITU-T X.511 (1997) Technical Cor. 3 2005-05-14 17 11.1002/1000/8503
4.0 ITU-T X.511 2001-02-02 7 11.1002/1000/5315
4.1   ITU-T X.511 (2001) Technical Cor. 1 2005-05-14 17 11.1002/1000/8504
4.2   ITU-T X.511 (2001) Technical Cor. 2 2005-11-29 17 11.1002/1000/8635
4.3   ITU-T X.511 (2001) Cor. 3 2008-05-29 17 11.1002/1000/9433
5.0 ITU-T X.511 2005-08-29 17 11.1002/1000/8502
5.1   ITU-T X.511 (2005) Cor. 1 2008-05-29 17 11.1002/1000/9434
5.2   ITU-T X.511 (2005) Cor. 2 2008-11-13 17 11.1002/1000/9594
5.3   ITU-T X.511 (2005) Cor. 3 2011-02-13 17 11.1002/1000/11044
5.4   ITU-T X.511 (2005) Cor. 4 2012-04-13 17 11.1002/1000/11586
6.0 ITU-T X.511 2008-11-13 17 11.1002/1000/9593
6.1   ITU-T X.511 (2008) Cor. 1 2011-02-13 17 11.1002/1000/11045
6.2   ITU-T X.511 (2008) Cor. 2 2012-04-13 17 11.1002/1000/11587
6.3   ITU-T X.511 (2008) Cor. 3 2012-10-14 17 11.1002/1000/11737
7.0 ITU-T X.511 2012-10-14 17 11.1002/1000/11738
8.0 ITU-T X.511 2016-10-14 17 11.1002/1000/13033
9.0 ITU-T X.511 2019-10-14 17 11.1002/1000/14034
9.1   ITU-T X.511 (2019) Amd. 1 2024-10-29 17 11.1002/1000/16173

To access the Recommendation, type the URL https://handle.itu.int/ in the address field of your web browser, followed by the
Recommendation's unique ID.
Rec. ITU-T X.511 (2019) Amd. 1 (10/2024)
© ISO/IEC 2025 – All rights reserved
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ISO/IEC 9594-3:2020/Amd. 1:2025(en)
FOREWORD
The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of
telecommunications, and information and communication technologies (ICTs). The ITU Telecommunication
Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical,
operating and tariff questions and issuing Recommendations on them with a view to standardizing
telecommunications on a worldwide basis.
The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes
the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.
The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
In some areas of information technology
...