ITU-T Recommendations

Recommendation ITU-T H.225.0 covers the technical requirements for narrow-band visual telephone services defined in H.200 and F.720-series Recommendations, in those situations where the transmission path includes one or more packet-based networks, each of which is configured and managed to provide a non-guaranteed Quality of Service (QoS) which is not equivalent to that of N ISDN, such that additional protection or recovery mechanisms beyond those mandated by Rec. ITU T H.320 need be provided in the terminals. It is noted that Rec. ITU-T H.322 addresses the use of some other LANs which are able to provide the underlying performance not assumed by ITU T Recs H.323 and H.225.0.
This Recommendation describes how audio, video, data, and control information on a packet-based network can be managed to provide conversational services in H.323 equipment.
Products claiming compliance with Version 8 of H.225.0 (this version) shall comply with all of the mandatory requirements of this Recommendation. Version 8 products can be identified by H.225.0 messages containing a protocolIdentifier value of {itu-t (0) recommendation (0) h (8) 2250 version (0) 8}.
This revision incorporates the following changes:
1) Enhancements for language capability exchange.
2) Modification to the scope regarding use on the Internet.
3) Clarification that the Facility message may be used to initiate call transfer.