T.120

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	Refs
T.120	Data protocols for multimedia conferencing	In force	^[6]
T.121	Generic application template	In force	^[7]
T.122	Multipoint communication service - Service definition	In force	^[8]
T.123	Network-specific data protocol stacks for multimedia conferencing	In force	^[9]
T.124	Generic Conference Control	In force	^[10]
T.125	Multipoint communication service protocol specification	In force	^[11]
T.126	Multipoint still image and annotation protocol	In force	^[12]
T.127	Multipoint binary file transfer protocol	In force	^[13]
T.128	Multipoint application sharing^[a]	In force	^[14]^[15]
T.130	Realtime architecture	?	^[15]
T.131	Network specific mappings	?	^[15]
T.132	Realtime link management	?	^[15]
T.133	Audio visual control services	?	^[15]
T.134	Text chat application entity	In force	^[16]
T.135	User-to-reservation system transactions within T.120 conferences	In force	^[17]
T.136	Remote device control application protocol	Superseded by H.281	^[18]^[19]
T.137	Virtual meeting room management for multimedia conferencing audio-visual control	In force	^[20]
T.RES	Reservation services	?	^[3]^[15]
T.TUD	User reservation	?	^[3]^[15]

^ T.128 was previously called T.Share while in draft stage.

References

^ ^a ^b Clark, W. J. (1994). "Protocols for Multimedia Conferencing: An Introduction to the ITU-T T.120 series". In Hutchison, D.; Danthine, A.; Leopold, H.; Coulson, G. (eds.). Proceedings of the International COST 237 Workshop on Multimedia Transport and Teleservices. Springer-Verlag. p. 322. doi:10.1007/3-540-58759-4_43.
^ "Evaluation of Shared Display in WebEx and VNC". Community Grids Heritage Web Server: Summer 2000–2001. Indiana University Bloomington. Section: "Network communication". Retrieved 13 March 2018.
^ ^a ^b ^c United States patent 6317777B1, Rune A. Skarbo; Christopher C. Lawless & Puneet Kukkal et al., "Method for web based storage and retrieval of documents", issued 2001-11-13, assigned to Intel
^ Chiabra, Roberto. "What's New in Sametime 8.5" (PDF). IBM DeveloperWorks. IBM. Retrieved 13 March 2018.
^ ^a ^b Zwicky, Elizabeth D.; Cooper, Simon; Chapman, D. Brent (June 2000). "Multimedia Protocols". Building Internet Firewalls (2nd ed.). O'Reilly Media. Subsection: "Packet filtering characteristics of T.120". ISBN 978-1-56592-871-8. OCLC 639935671. Retrieved 20 February 2018.
^ "T.120 : Data protocols for multimedia conferencing". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.121 : Generic application template". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.122 : Multipoint communication service - Service definition". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.123 : Network-specific data protocol stacks for multimedia conferencing". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.124 : Generic Conference Control". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.125 : Multipoint communication service protocol specification". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.126 : Multipoint still image and annotation protocol". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.127 : Multipoint binary file transfer protocol". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.128 : Multipoint application sharing". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ ^a ^b ^c ^d ^e ^f ^g Freedman, Alan. "T.120". Computer Desktop Encyclopedia. The Computer Language Company. Retrieved 3 March 2018.
^ "T.134 : Text chat application entity". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.135 : User-to-reservation system transactions within T.120 conferences". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.136 : Text chat application entity". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "H.281 : A far end camera control protocol for videoconferences using H.224". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.
^ "T.137 : Virtual meeting room management for multimedia conferencing audio-visual control". ITU.int. International Telecommunication Union. Retrieved 3 March 2018.