To achieve greater scalability, this Recommendation decomposes the H.323 Gateway function defined in ITU-T Rec. H.246 into functional subcomponents and specifies the protocols these components use to communicate. This allows implementations of H.323 gateways to be highly scalable and encourages leverage of widely deployed Switched Circuit Network (SCN) capabilities such as SS7 switches. This also enables H.323 gateways to be composed of components from multiple vendors distributed across multiple physical platforms. The purpose of this Recommendation is to add capabilities currently defined for H.323 systems and is intended to provide new ways of performing operations already supported in H.323.
This Recommendation includes several enhancements to ITU-T Rec. H.248.1 Version 1:
- individual property, signal, event and statistic auditing;
- improved multiplex handling;
- topology for streams;
- improved description of profiles;
- serviceChange capability change.
Corrigendum 1 corrects several defects found in the Recommendation, in particular:
• Specification of types for rtp/jit and rtp/delay in E.12.4;
• Definition of the '#' symbol in the "unequal" construct in text encoding;
• Definition of the symbol for the NULL context in text encoding;
• Corrections: to Appendix I example statistics, package guidelines for statistics in 12.1.5; ambiguous audit and individual audit return; Context Audit Return; Typographical error in 7.1.2;
• Specification of the meaning of "automatic" in E.13 "TDM Package";
• Additional codepoint and of binary value for packetization time in Annex C;
• Clarification of wildcarding principles and of wildcarding in the Topology Descriptor;
• Clarification of: statistics and the Move command; modification of terminations by MGCs; optional commands in an action; ordering of transactions; precedence of LocalControl mode property versus SDP mode; Digit processing; usage of digitmap timer symbols with range notation; use of StreamID = 0; AuditCapabilities return for string values; protocol version negotiation;
• Clarification that the network package can apply to TDM.
NOTE – This Recommendation comprises the renumbering of ITU-T Rec. H.248, its Annexes A through E, and its Appendix I.