T.120 Explained

T.120 is a suite of point-to-multipoint communication protocols for teleconferencing, videoconferencing, and computer-supported collaboration.^[1] It provides for application sharing, online chat, file sharing, and other functions. The protocols are standardised by the ITU Telecommunication Standardization Sector (ITU-T).^[1]

T.120 has been implemented in various real-time collaboration programmes, including WebEx and NetMeeting.^{[2] [3]} IBM Sametime switched from the T.120 protocols to HTTP(S) in version 8.5.^[4]

The prefix T designates the ITU subcommittee that developed the standard, but it is not an abbreviation. The ITU (re)assigns these prefixes to committees incrementally and in alphabetic order.^[5]

The T.123 standard specifies that T.120 protocols use network port 1503 when communicating over TCP/IP.^[5]

Components

Number	Title	Status
	T.120	Data protocols for multimedia conferencing		^[6]
	T.121	Generic application template		^[7]
	T.122	Multipoint communication service - Service definition		^[8]
	T.123	Network-specific data protocol stacks for multimedia conferencing		^[9]
	T.124	Generic Conference Control		^[10]
	T.125	Multipoint communication service protocol specification		^[11]
	T.126	Multipoint still image and annotation protocol		^[12]
	T.127	Multipoint binary file transfer protocol		^[13]
	T.128	Multipoint application sharing		^[14] ^[15]
	T.130	Realtime architecture
	T.131	Network specific mappings
	T.132	Realtime link management
	T.133	Audio visual control services
	T.134	Text chat application entity		^[16]
	T.135	User-to-reservation system transactions within T.120 conferences		^[17]
	T.136	Remote device control application protocol		^[18] ^[19]
	T.137	Virtual meeting room management for multimedia conferencing audio-visual control		^[20]
	T.RES	Reservation services
	T.TUD	User reservation

Notes and References

1. Protocols for Multimedia Conferencing: An Introduction to the ITU-T T.120 series . Clark . W. J. . Proceedings of the International COST 237 Workshop on Multimedia Transport and Teleservices . 1994 . Hutchison . D. . Danthine . A. . Leopold . H. . Coulson . G. . Springer-Verlag . 322 . 10.1007/3-540-58759-4_43.
2. Web site: Evaluation of Shared Display in WebEx and VNC . Section: "Network communication" . Community Grids Heritage Web Server: Summer 2000–2001 . Indiana University Bloomington . 2018-03-13.
3. United States . 6317777B1 . patent . Method for web based storage and retrieval of documents . 2001-11-13 . 1999-04-26 . Rune A. Skarbo . Cameron J. Clitheroe . Christopher C. Lawless . Puneet Kukkal . Stephen D. Hochman . .
4. Web site: What's New in Sametime 8.5 . Chiabra . Roberto . . IBM . 2018-03-13.
5. Book: Zwicky, Elizabeth D. . https://docstore.mik.ua/orelly/networking_2ndEd/fire/ch19_04.htm . Building Internet Firewalls . 2nd . Cooper . Simon . Chapman . D. Brent . Multimedia Protocols . Subsection: "Packet filtering characteristics of T.120" . . June 2000 . 978-1-56592-871-8 . 639935671 . 2018-02-20 . registration .
6. Web site: T.120 : Data protocols for multimedia conferencing . ITU.int . International Telecommunication Union . 2018-03-03.
7. Web site: T.121 : Generic application template . ITU.int . International Telecommunication Union . 2018-03-03.
8. Web site: T.122 : Multipoint communication service - Service definition . ITU.int . International Telecommunication Union . 2018-03-03.
9. Web site: T.123 : Network-specific data protocol stacks for multimedia conferencing . ITU.int . International Telecommunication Union . 2018-03-03.
10. Web site: T.124 : Generic Conference Control . ITU.int . International Telecommunication Union . 2018-03-03.
11. Web site: T.125 : Multipoint communication service protocol specification . ITU.int . International Telecommunication Union . 2018-03-03.
12. Web site: T.126 : Multipoint still image and annotation protocol . ITU.int . International Telecommunication Union . 2018-03-03.
13. Web site: T.127 : Multipoint binary file transfer protocol . ITU.int . International Telecommunication Union . 2018-03-03.
14. Web site: T.128 : Multipoint application sharing . ITU.int . International Telecommunication Union . 2018-03-03.
15. Web site: T.120 . Computer Desktop Encyclopedia . Freedman . Alan . The Computer Language Company . 2018-03-03.
16. Web site: T.134 : Text chat application entity . ITU.int . International Telecommunication Union . 2018-03-03.
17. Web site: T.135 : User-to-reservation system transactions within T.120 conferences . ITU.int . International Telecommunication Union . 2018-03-03.
18. Web site: T.136 : Text chat application entity . ITU.int . International Telecommunication Union . 2018-03-03.
19. Web site: H.281 : A far end camera control protocol for videoconferences using H.224 . ITU.int . International Telecommunication Union . 2018-03-03.
20. Web site: T.137 : Virtual meeting room management for multimedia conferencing audio-visual control . ITU.int . International Telecommunication Union . 2018-03-03.