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Short History of Study Group 17

​The following is a short history of Study Group 17 and the related X-series and Z-series of Recommendations. 

As many people know, SG 17 was formed by the merger of ITU-T Study Groups 7 and 10 in 2001. 

Study Group 7 had its roots back to the Joint Working Party on New Data Networks, which was created by the IVth Plenary Assembly of the CCITT (Consultative Committee for International Telephony and Telegraphy) in 1968. Table 1 below shows the evolution over the various study periods and the study group leadership until the merger with SG 10 in 2001. Its work program evolved significantly over this time. In the late 60s and early 70s, its​ work focused on digital leased lines and digital circuit switched data networks with the first X-series Recommendations approved at the December 1972 Vth CCITT Plenary Assembly. Packet switched networks was the hot topic of the 70s and 80s with the first edition of the famous X.25 Recommendation approved in 1976. An ever increasing number of packet data network Recommendations were developed and approved in 1980, 1984 and 1988. Work on Open Systems Interconnection (OSI) in conjunction with ISO and IEC began in the early 80s and was very intense through the 80s and 90s. By 2000, this work had reached maturity and SG 7 began to build its efforts on security.

Study Group 10 had its roots as part of the work of CCITT Study Group XI with three Questions (out of eleven Questions) on languages for stored program control telephone exchanges adopted by the Vth CCITT Plenary Assembly in 1972. Table 2 below shows the evolution over the various study periods and the study group leadership until the merger with SG 7 in 2001. In 1976, skeleton Recommendations on Specification and Description Language (SDL) and Man-Machine Language (MML) were adopted as the first Z-series Recommendations. These were further developed in the next 8 years along with CHILL with approvals in 1980 and 1984. The VIIIth CCITT Plenary Assembly in October 1984 established Study Group 10. By 2000, a suite of Z-series Recommendations was in place with MSC (Message Sequence Chart) as the major addition in the 1990s. Focus in the later years moved to aligning ITU-T languages, such as SDL and MSC, to OMG’s UML (Unified Modeling Language).

In 2001, TSAG agreed to merge Study Groups 7 and 10 to form Study Group 17 (7 + 10 = 17). The chairman of the two study groups became co-chairmen of the new Study Group 17 and all the vice chairmen of the two study groups became vice chairman of the new Study Group 17. Table 3 below shows the evolution of Study Group 17 over five study periods and the study group leadership. A major change was made at WTSA-04 when the remaining work on data network was transferred to Study Group 13 and the major focus of Study Group 17 was shifted to security while also continuing its work on languages. By WTSA-08, a substantial set of security Recommendations had been approved and WTSA-08 changed the title of Study Group 17 to Security. The role of Study Group 17 was essentially continued by WTSA-12 and strengthened by WTSA-16.  Study Group 17 has lead study group responsibilities for:
         -     Security
         -     Identity management (IdM)
         -     Languages and description techniques

Table 4 shows the history of X and Z series Recommendations approved by the various CCITT Plenary Assemblies. After 1988, Recommendations were developed, approved and published individually, rather than in the sequence of color books published every four years. The X-series expanded in scope over the years from “New data networks” to “Data communication networks” to “Data networks and open system communications” to “Data networks, open system communications and security”. In a similar​​ manner, the Z-series expanded over the years from “Programming languages for SPC exchanges" to "Programming languages”, to “Languages and general software aspects for telecommunication systems”. Tables 5, 6, 7 and 8 show the set of 396 approved Recommendations and 33 approved Supplements under the responsibility of Study Group 17 as of 1 July 2020, among which over 200 standards (ITU-T Recommendations) focus on security.

Table 1 - Leadership of Study Group 7 and predecessors

Study Period Designation Name Chairman Vice Chairmen Number of Questions
1969-1972JWP/NRDNew data networksO. A. OHLMER (Germany)V. C. MACDONALD (Canada)1
1973-1976Study Group VIINew networks for data transmissionV. C. MACDONALD (Canada)N. R. CRANE (Australia)
H. GABLER (Germany)
A. E. SERRURE (Belgium)
1 (25 points)
1977-1980Study Group VIINew networks for data transmissionV. C. MACDONALD (Canada)J. CHAPMAN (UK)
N. R. CRANE (Australia)
M. KATO (Japan)
A. TEXIER (France)
1981-1984Study Group VIIData communication networksV. C. MACDONALD (Canada)H. V. BERTINE (USA)
M. KATO (Japan)
L. Lavandera SANCHEZ (Spain)
A. TEXIER (France)
1985-1988Study Group VIIData communication networksJ. O. WEDLAKE (UK)H. V. BERTINE (USA)
P. G. BOWIE (Canada)
L. Lavandera SANCHEZ (Spain)
R. PARODI (Italy)
S. TOMITA (Japan)
1989-1992Study Group VIIData communications networksJ. O. WEDLAKE (UK)H. V. BERTINE (USA)
P. G. BOWIE (Canada)
L. Lavandera SANCHEZ (Spain)
J. PARK (Australia)
R. PARODI  (Italy)
P. PUGES (France)
S. TOMITA  (Japan)
1993-1996Study Group 7Data networks and open systems communicationsH. V. BERTINE (USA)V. OSSIPOV (Russia)
S. TOMITA  (Japan)
C. H. YIM (Korea)
1997-2000Study Group 7Data networks and open system communicationsH. V. BERTINE (USA)Y. H. LEE (Korea)
V. OSSIPOV (Russia)
2001-16/9/01Study Group 7Data networks and open systems communicationsH. V. BERTINE (USA)B.-M. CHIN (Korea)
V. OSSIPOV  (Russia)

Table 2 - Leadership of Study Group 10 and predecessors

Study Period Designation Name Chairman Vice Chairmen Number of Questions
1973-1976Study Group XITelephone switching and signallingJ. S. RYAN (USA)T. MOUSSA (Cameroon)
P. PLEHIERS (Belgium)
3 out of 11
1977-1980Study Group XITelephone switching and signallingJ. S. RYAN (USA)C. A. ADEOYE (Nigeria)
P. PLEHIERS  (Belgium)
3 out of 13
1981-1984Study Group XITelephone switching and signallingJ. S. RYAN (USA)P. COLLET (France)
S. KANO (Japan)
P. PLEHIERS  (Belgium)P. STERNDORFF(Denmark)
3 out of 19
1985-1988Study Group XLanguages and methods for telecommunications applicationsC. CARRELLI (Italy)K. KATZEFF (Sweden)
K. SCHULZ (Germany)
1989-1992Study Group XLanguages for telecommunication applicationsC. CARRELLI (Italy)O. F. FAERGEMAND (Denmark)
K. SCHULZ (Germany)
1993-1996Study Group 10Languages for telecommunication applicationsO. F. FAERGEMAND (Denmark)K. SCHULZ (Germany)10
1997-2000Study Group 10Languages and general software aspects for telecommunication systemsA. SARMA (Germany)A. MEISINGSET (Norway)13
2001-16/9/2001Study Group 10Languages and general software aspects for telecommunication systemsA. SARMA (Germany)V. EFIMOUCHKINE (Russia)

Table 3 - Leadership of Study Group 17

Study Period Designation Name Chairman Vice Chairmen Number of Questions
17/9/2001-2004Study Group 17Data networks and telecommunication softwareCo-chairmen:
Amardeo SARMA (Germany)
Byoung-Moon CHIN (Korea)
Vladimir EFIMOUCHKINE (Russia)
Arve MEISINGSET (Norway)
Ostap MONKEWICH (Canada)
V. OSSIPOV (Russia)
2005-2008Study Group 17Security, languages and telecommunication softwareHerbert BERTINE (USA)Jianyong CHEN (China)
Byoung-Moon CHIN (Korea)
Arkadiy KREMER (Russia)
Arve MEISINGSET (Norway)
Ostap MONKEWICH (Canada)
2009-2012Study Group 17Security Arkadiy KREMER (Russia)Jianyong CHEN (China)
Mohamed M.K. ELHAJ (Sudan)
Antonio GUIMARAES (Brazil)
Patrick MWESIGWA (Uganda)
Koji NAKAO (Japan)
Heung Youl YOUM (Korea)
​2013-2016​Study Group 17​Security Arkadiy KREMER (Russia)Khalid BELHOUL (UAE)
Mohamed M.K. ELHAJ (Sudan)
Mario German Fromow RANGEL (Mexico)
Antonio GUIMARAES (Brazil)
Zhaoji LIN (China)
Patrick MWESIGWA​ (Uganda)
Koji NAKAO (Japan)
Sacid SARIKAYA (Turkey)
Heung Youl YOUM (Korea)
​2017-2020​​Study Group 17 ​Security​Heung Youl YOUM (Korea)​Vasily DOLMATOV (Russia)
Gökhan EVREN (Turkey)
Inette FUREY (USA)*
Muataz Elsadig ISHAG (Sudan)
Patrick-Kennedy KETTIN ZANGA (Central African Republic)
Wala LATROUS (Tunisia)
Zhaoji LIN (China)
Hugo Darío MIGUEL (Argentina)**
Yutaka MIYAKE (Japan)​
 * Replaced by Juan Gonzalez(USA), March 2018 
** Replaced by Lia Molinari (Argentina), March 2020

Table 4 - CCITT Plenary Assemblies and Recommendations Approved

Study Period Book Plenary Assembly Dates X-series Recommendations Z-series Recommendations
1969-1972Green BookVth CCITT Plenary Assembly4-15 December 197211 (Public data networks - X.1, X.2, X.20, X.21, X.30, X.31, X.32, X.33, X.40, X.50, X.70)
1973-1976Orange BookVIth CCITT Plenary Assembly27 September – 8 October 197624 (Public data networks)3 (SDL – Z.100-series)
8 (MML – Z.300-series)
1977-1980Yellow BookVIIth CCITT Plenary Assembly10-21 November 198039 (Public data networks)4 (SDL – Z.100-series)
1 (CHILL – Z.200)
9 (MML – Z.300-series)
1981-1984Red BookVIIIth CCITT Plenary Assembly8-19 October 198456 (Public data networks)
9 (OSI – X.200-series)
8 (MHS – X.400-series)
5 (SDL – Z.100-series)
1 (CHILL – Z.200)
15 (MML – Z.300-series)
1985-1988Blue BookIXth CCITT Plenary Assembly14-25 November 198872 (Public data networks)
23 (OSI – X.200-series)
9 (MHS – X.400-series)
8 (Directory – X.500-series)
1 (SDL – Z.100)
1 (FDTs – Z.110)
1 (CHILL – Z.200)
19 (MML – Z.300-series)

Table 5 - E-series Recommendations under the responsibility of Study Group 17*


Subject Recommendation Series Number of Texts
International operation E.100-E.229 2
General provisions concerning Administrations E.104-E.1192
Network management E.400-E.489 1
International network managementE.405-E.4191
* These 3 Recommendations are in conjunction with Study Group 2

Table 6 - F-series Recommendations under the responsibility of Study Group 17


Subject Recommendation Series Number of Texts
​Telegraph service ​F.1-F.109 1
Message handling services F.400-F.499 11
Directory services F.500-F.549 4

Table 7 - X-series Recommendations under the responsibility of Study Group 17


Subject Recommendation Series Number of Texts
Open Systems Interconnection X.200-X.299 48
Model and notationX.200-X.209 2
Service definitions X.210-X.219 11
Connection-mode protocol specifications X.220-X.229 10
Connectionless-mode protocol specifications X.230-X.239 6
PICS proformas X.240-X.259 8
Protocol Identification X.260-X.269 3
Security Protocols X.270-X.279 2
Layer Managed Objects X.280-X.289 5
Conformance testingX.290-X.299 1
Message Handling Systems X.400-X.499 25
Directory X.500-X.599 10
OSI networking and system aspects X.600-X.699 42 + 1 Supp.
Efficiency X.630-X.6396
Quality of service X.640-X.6492
Naming, Addressing and Registration X.650-X.67915 + 1 Supp.
Abstract Syntax Notation One (ASN.1) X.680-X.69912
Security X.800-X.849 20 + 5 Supp.
OSI applications X.850-X.899 14
Commitment, Concurrency and RecoveryX.850-X.8593
Transaction processingX.860-X.8794
Remote operationsX.880-X.8893
Generic applications of ASN.1X.890-X.8994
Open distributed processing X.900-X.999 13
Information and network security X.1000-X.1099 40 + 5 Supp.
General security aspectsX.1000-X.10290
Network securityX.1030-X.104915 + 1 Supp.
Security managementX.1050-X.10699+ 4 Supp.
Secure applications and services (1) X.1100-X.1199 42 + 6 Supp.
Multicast securityX.1100-X.11091
Home network security
X.1110-X.1119 4 + 1 Supp.
Mobile securityX.1120-X.11397 + 2 Supp.
Web securityX.1140-X.11498 + 3 Supp.
Security protocols (1)
Peer-to-peer securityX.1160-X.11694
Networked ID securityX.1170-X.11791
IPTV securityX.1180-X.11998
Cyberspace security X.1200-X.1299 36 + 15 Supp.
CybersecurityX.1200-X.122911 + 5 Supp.
Countering spamX.1230-X.124912 + 8 Supp.
Identity management 
X.1250-X.127913 + 2 Supp.
Secure applications and services (2) X.1300-X.149920
Emergency communicationsX.1300-X.13092
Ubiquitous sensor network security
​Smart grid security
​Certified mail
​Internet of things (IoT) security
​Intelligent transportation system (ITS) security
​​Distributed ledger technology security
​​​​Security protocols (2)
Cybersecurity information exchange​ ​X.1500-X.1599 ​21
​Overview of cybersecurity
Vulnerability/state exchange​
Event/incident/heuristics exchange​​X.1540-X.1549​4
Exchange of policies​​X.1550-X.1559​1
Heuristics and information request​​X.1560-X.1569​0
Identification and discovery​​X.1570-X.1579​1
Assured exchange​​X.1580-X.1589​3
Cloud computing security​X.1600-X.1699 8
​     ​Overview of cloud computing security
​     Cloud Computing security design
​      X.1602-X.1639
​     Cloud Computing security best practices and guidelines
Quantum communication
​     Quantum random number generator
​      X.1702-X.17.09
Data security
​     Big Data Security
​      X.1750-X.1759
5G security

Table 8 - Z-series Recommendations under the responsibility of Study Group 17


Subject Recommendation Series Number of Texts
Formal description techniques (FDT) Z.100-Z.199 35 + 1 Supp.
Specification and Description Language (SDL) Z.100-Z.109 9 + 1 Supp.
Application of formal description techniques Z.110-Z.119 3
Message Sequence Chart (MSC) Z.120-Z.129 2
User Requirements Notation (URN) Z.150-Z.159 2
Testing and Test Control Notation (TTCN)Z.160-Z.179 19
Programming languages Z.200-Z.299 1
CHILL: The ITU-T high level languageZ.200-Z.209 1
Quality Z.400-Z.499 1
Quality of telecommunication softwareZ.400-Z.409 0
Quality aspects of protocol-related RecommendationsZ.450-Z.459 1
Middleware Z.600-Z.699 0
Processing environment architecturesZ.600-Z.609 0