Summary

Recommendation ITU‑T H.245 specifies syntax and semantics of terminal information messages as well as procedures to use them for in-band negotiation at the start of or during communication. The messages cover receiving and transmitting capabilities as well as mode preference from the receiving end, logical channel signalling, and Control & Indication. Acknowledged signalling procedures are specified to ensure reliable audiovisual and data communication.

Products claiming compliance with Version 17 of Recommendation ITU‑T H.245 shall comply with all of the mandatory requirements of this Recommendation. Version 17 products can be identified by Recommendation ITU‑T H.245 TerminalCapabilitySet messages containing a protocolIdentifier value of {ITU‑T (0) recommendation (0) h (8) 245 version (0) 17}.

Relative to Recommendation ITU‑T H.245 Version 16 (2011), this version incorporates the following changes:

–           Add procedures in Annex V to support better interoperability between IPv4 and IPv6 devices.

–           Updated Table VIII.1 to support the revisions made to Recommendation ITU‑T H.241.

–           Support of an SCTP media transport in H.323 systems, including the addition of Annex U.

–           Support of DTLS media transport in H.323 systems, including the addition of Annex U.

–           Support of out of band data channel establishment for Annex U.

–           Propose updates to Recommendation ITU‑T H.245 to support SCTP: split dtls-sctp into udp‑dtls-sctp and tcp-dtls-sctp.

–           Add ExtendedAudioCapability and ExtendedDataCapability in Recommendation ITU‑T H.245.