Summary

This Recommendation 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 ITU-T Rec. H.320 need be provided in the terminals. It is noted that ITU-T Rec. H.322 addresses the use of some other LANs which are able to provide the underlying performance not assumed by the 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 6 of H.225.0 (this version) shall comply with all of the mandatory requirements of this Recommendation. Version 6 products can be identified by H.225.0 messages containing a protocolIdentifier value of {itu-t (0) recommendation (0) h (8) 2250 version (0) 6}.

This revision brings the following features:

1)��������� Extension to H.225.0 AliasAddress to support digit codes 10 to 14.

2)��������� Added the capability of a gatekeeper to assign an E.164 alias to an endpoint that does not register any by itself.

3)��������� Added no-bandwidth error code in H.225.0 AdmissionRejectReason.

4)��������� ASN.1 and text changes required for Assigned Gatekeeper procedures.

5)��������� Changes to Clause 7.5 to add the requirement to re-start T310 timer when a PI value of 1 or 8 is received.

6)��������� Changes to H.225.0 ASN to take care of H.361 changes.

7)��������� Changes to ASN.1 definition and text to address the addition of 'language' field in LRQ and RRQ structures for new Rec. H.460.21 (ex H.460.MB).

8)��������� Corrected a spelling mistake in the comments for unallocatedNumber in ASN.1 specification.

This revision also clarifies text or corrects errors previously identified in Implementors' Guides: added mapping tables for LocationRejectReason/AdmissionRejectReason and AccessRejectionReason/AdmissionRejectReason, clarified the description of the insertion of additionalSourceAddresses by a gatekeeper, and the text on the use of Facility message to carry h245Address, and corrected text describing length of UUIE field.