Rec. ITU-T H.225.0 (03/2022) iii
Table of Contents
Page
1 Scope ............................................................................................................................ 1
2 References..................................................................................................................... 3
3 Definitions .................................................................................................................... 5
4 Abbreviations and acronyms ........................................................................................ 5
4.1 General abbreviations ..................................................................................... 5
4.2 RAS message abbreviations ........................................................................... 7
5 Conventions .................................................................................................................. 7
6 Packetization and synchronization mechanism ............................................................ 8
6.1 General approach ............................................................................................ 8
6.2 Use of RTP/RTCP .......................................................................................... 11
7 H.225.0 message definitions ......................................................................................... 14
7.1 Use of Q.931 messages ................................................................................... 14
7.2 Common Q.931 information elements ........................................................... 17
7.3 Q.931 based H.225.0 call signalling message details ..................................... 27
7.4 Q.932-based H.225.0 call signalling message details .................................... 41
7.5 H.225.0 call signalling timer values ............................................................... 46
7.6 H.225.0 common message elements .............................................................. 46
7.7 Required support of RAS messages ............................................................... 60
7.8 Terminal and gateway discovery messages .................................................... 61
7.9 Terminal and gateway registration messages ................................................. 63
7.10 Terminal/gatekeeper unregistration messages ................................................ 69
7.11 Terminal to gatekeeper admission messages .................................................. 71
7.12 Terminal to gatekeeper requests for changes in bandwidth ........................... 76
7.13 Location request messages ............................................................................. 78
7.14 Disengage messages ....................................................................................... 82
7.15 Status request messages .................................................................................. 84
7.16 Non-standard message .................................................................................... 88
7.17 Message not understood ................................................................................. 89
7.18 Gateway resource availability messages ........................................................ 89
7.19 RAS timers and Request in Progress (RIP) .................................................... 90
7.20 Service control messages ................................................................................ 92
7.21 AdmissionConfirmSequence .......................................................................... 94
7.22 Error Code Mapping ....................................................................................... 94
8 Mechanisms for maintaining QoS ................................................................................ 95
8.1 General approach and assumptions ................................................................ 95
8.2 Use of RTCP in measuring QoS ..................................................................... 96
8.3 Audio/Video jitter procedures ........................................................................ 96
8.4 Audio/Video skew procedures ....................................................................... 97
