Recommendation ITU-T H.225.0 (03/2022) Call signalling protocols and media stream packetization for packet-based multimedia communication systems
Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
4 Abbreviations and acronyms
     4.1 General abbreviations
     4.2 RAS message abbreviations
5 Conventions
6 Packetization and synchronization mechanism
     6.1 General approach
     6.2 Use of RTP/RTCP
          6.2.1 Audio
          6.2.2 Video messages
          6.2.3 Data messages
7 H.225.0 message definitions
     7.1 Use of Q.931 messages
     7.2 Common Q.931 information elements
          7.2.1 Header information elements
               7.2.1.1 Protocol discriminator
               7.2.1.2 Call reference
               7.2.1.3 Message type
          7.2.2 Message-specific information elements
               7.2.2.1 Bearer capability
                    7.2.2.1.1 Bearer capability default encoding
                    7.2.2.1.2 Bearer capability encoding for H.450.1 call-independent signalling connections
               7.2.2.2 Call identity
               7.2.2.3 Call state
               7.2.2.4 Called party number
               7.2.2.5 Called party subaddress
               7.2.2.6 Calling party number
               7.2.2.7 Calling party subaddress
               7.2.2.8 Cause
               7.2.2.9 Channel identification
               7.2.2.10 Connected number
               7.2.2.11 Connected sub-address
               7.2.2.12 Congestion level
               7.2.2.13 Date/time
               7.2.2.14 Display
               7.2.2.15 Extended facility information element
               7.2.2.16 Facility
               7.2.2.17 High layer compatibility
               7.2.2.18 Keypad facility
               7.2.2.19 Low layer compatibility
               7.2.2.20 More data
               7.2.2.21 Network-specific facilities
               7.2.2.22 Notification indicator
               7.2.2.23 Progress indicator
               7.2.2.24 Redirecting number
               7.2.2.25 Repeat indicator
               7.2.2.26 Restart indicator
               7.2.2.27 Segmented message
               7.2.2.28 Sending complete
               7.2.2.29 Signal
               7.2.2.30 Transit network selection
               7.2.2.31 User-user
     7.3 Q.931 based H.225.0 call signalling message details
          7.3.1 Alerting
          7.3.2 Call proceeding
          7.3.3 Connect
          7.3.4 Connect acknowledge
          7.3.5 Disconnect
          7.3.6 Information
          7.3.7 Progress
          7.3.8 Release
          7.3.9 Release complete
          7.3.10 Setup
               7.3.11 Setup acknowledge
               7.3.12 Status
          7.3.13 Status inquiry
     7.4 Q.932-based H.225.0 call signalling message details
          7.4.1 Facility
          7.4.2 Notify
          7.4.3 Other messages
     7.5 H.225.0 call signalling timer values
     7.6 H.225.0 common message elements
     7.7 Required support of RAS messages
     7.8 Terminal and gateway discovery messages
          7.8.1 GatekeeperRequest (GRQ)
          7.8.2 GatekeeperConfirm (GCF)
          7.8.3 GatekeeperReject (GRJ)
     7.9 Terminal and gateway registration messages
          7.9.1 RegistrationRequest (RRQ)
          7.9.2 RegistrationConfirm (RCF)
          7.9.3 RegistrationReject (RRJ)
     7.10 Terminal/gatekeeper unregistration messages
          7.10.1 UnregistrationRequest (URQ)
          7.10.2 UnregistrationConfirm (UCF)
          7.10.3 UnregistrationReject (URJ)
     7.11 Terminal to gatekeeper admission messages
          7.11.1 AdmissionRequest (ARQ)
          7.11.2 AdmissionConfirm (ACF)
          7.11.3 AdmissionReject (ARJ)
     7.12 Terminal to gatekeeper requests for changes in bandwidth
          7.12.1 BandwidthRequest (BRQ)
          7.12.2 BandwidthConfirm (BCF)
          7.12.3 BandwidthReject (BRJ)
     7.13 Location request messages
          7.13.1 LocationRequest (LRQ)
          7.13.2 LocationConfirm (LCF)
          7.13.3 LocationReject (LRJ)
     7.14 Disengage messages
          7.14.1 DisengageRequest (DRQ)
          7.14.2 DisengageConfirm (DCF)
          7.14.3 DisengageReject (DRJ)
     7.15 Status request messages
          7.15.1 InfoRequest (IRQ)
          7.15.2 InfoRequestResponse (IRR)
          7.15.3 InfoRequestAck (IACK)
          7.15.4 InfoRequestNak (INAK)
     7.16 Non-standard message
     7.17 Message not understood
     7.18 Gateway resource availability messages
          7.18.1 ResourcesAvailableIndicate (RAI)
          7.18.2 ResourcesAvailableConfirm (RAC)
     7.19 RAS timers and Request in Progress (RIP)
     7.20 Service control messages
          7.20.1 ServiceControlIndication (SCI)
          7.20.2 ServiceControlResponse (SCR)
     7.21 AdmissionConfirmSequence
     7.22 Error Code Mapping
8 Mechanisms for maintaining QoS
     8.1 General approach and assumptions
     8.2 Use of RTCP in measuring QoS
          8.2.1 Sender reports
          8.2.2 Receiver reports
     8.3 Audio/Video jitter procedures
     8.4 Audio/Video skew procedures
     8.5 Procedures for maintaining QoS
     8.6 Echo control
Annex A  RTP/RTCP
Annex B  RTP profile
Annex C  RTP payload format for H.261 video streams
Annex D  RTP payload format for H.261A video streams
     D.1 Introduction
     D.2 H.261A RTP packetization
Annex E  Video packetization
     E.1 H.263
Annex F  Audio and multiplexed packetization
     F.1 G.723.1
     F.2 G.728
     F.3 G.729
     F.4 Silence suppression
     F.5 GSM codecs
          F.5.1 Frame packetization
          F.5.2 Informative references
     F.6 G.722.1
     F.7 TIA/EIA-136 ACELP
          F.7.1 TIA/EIA-136 ACELP frame format
          F.7.2 TIA/EIA-136 ACELP silence suppression mode
          F.7.3 TIA/EIA-136 ACELP packetization
          F.7.4 TIA/EIA-136 ACELP referenced standard
     F.8 TIA/EIA-136 US1
          F.8.1 TIA/EIA-136 US1 frame format
          F.8.2 TIA/EIA-136 US1 silence mode frames (TX-DTX)
          F.8.3 TIA/EIA-136 US1 packetization
          F.8.4 TIA/EIA-136 US1 reference standard
     F.9 IS-127 EVRC
          F.9.1 IS-127 EVRC description
               F.9.1.1 General
               F.9.1.2 Compression rates
               F.9.1.3 Blanked packets
               F.9.1.4 Half rate
               F.9.1.5 Null 1/8 rate traffic channel data
          F.9.2 IS-127 EVRC packetization
               F.9.2.1 General requirements
               F.9.2.2 Frame formats
                    F.9.2.2.1 Full rate – F1
                    F.9.2.2.2 Half rate – F2
                    F.9.2.2.3 Eighth Rate – F3
          F.9.3 IS-127 EVRC reference standards
     F.10 H.223 MUX-PDU packetization
          F.10.1 Introduction
          F.10.2 MUX-PDU packetization format
Annex G  Communication between and within administrative domains
     G.1 Scope
     G.2 Definitions
     G.3 Abbreviations
     G.4 Normative references
     G.5 System models
          G.5.1 Hierarchical
          G.5.2 Distributed or full mesh
          G.5.3 Clearing house
          G.5.4 Aggregation point
          G.5.5 Overlapping Administrative Domains
     G.6 Operation
          G.6.1 Use of H.501 messages
          G.6.2 Address templates and descriptors
               G.6.2.1 Static configuration
               G.6.2.2 Receiving descriptors
               G.6.2.3 Receiving responses to specific queries
          G.6.3 Discovery of a Peer Element or set of Peer Elements
               G.6.3.1 Static
               G.6.3.2 Dynamic
               G.6.3.3 Other methods
          G.6.4 Resolution procedures
               G.6.4.1 Resolution procedure within Administrative Domains
               G.6.4.2 Resolution procedure between Administrative Domains
          G.6.5 Usage information exchange
               G.6.5.1 Multiple UsageIndications for the same call
               G.6.5.2 Requesting and negotiating usage information during service relationship establishment
          G.6.6 Number portability information signalling
     G.7 Signalling examples
          G.7.1 Distributed or full mesh
               G.7.1.1 Exchange of zone information
               G.7.1.2 Placing a call
          G.7.2 Clearing House
               G.7.2.1 Exchange of zone information
               G.7.2.2 Placing a call
     G.8 Annex G profiles
          G.8.1 Introduction
               G.8.1.1 Profile signalling and negotiation
                    G.8.1.1.1 Processing by the requesting entity
                    G.8.1.1.2 Processing by the responding entity
                    G.8.1.1.3 Identifiers
          G.8.2 Profile "A": Interzone call routing to a trusted gatekeeper
               G.8.2.1 Required messages
               G.8.2.2 Required fields
               G.8.2.3 Required procedures
               G.8.2.4 Identifiers for Profile "A"
Annex H  H.225.0 message syntax (ASN.1)
Annex I  H.263+ video packetization
Appendix I  RTP/RTCP algorithms
Appendix II  RTP profile
Appendix III  H.261 packetization
Appendix IV  H.225.0 operation on different packet-based network protocol stacks
     IV.1 TCP/IP/UDP
          IV.1.1 Discovering the gatekeeper
               IV.1.1.1 Discovery using multicast address or well-known port
               IV.1.1.2 Discovery using DNS (informative)
                    IV.1.1.2.1  A URL for gatekeepers
                    IV.1.1.2.2  Finding the URL
                         IV.1.1.2.2.1 The SRV resource record query
                         IV.1.1.2.2.2 The TXT record query
                    IV.1.1.2.3  Gatekeeper processing of email-IDs during ARQ and LRQ
          IV.1.2 Endpoint-to-endpoint communications
     IV.2 SPX/IPX
          IV.2.1 Discovering the gatekeeper
          IV.2.2 Endpoint-to-endpoint communication
     IV.3 SCTP
          IV.3.1 Streams
          IV.3.2 Payload protocol identifiers
Appendix V  ASN.1 usage in this Recommendation
     V.1 Tagging
     V.2 Types
     V.3 Constraints and ranges
     V.4 Extensibility
Appendix VI  H.225.0 identifiers of tunnelled signalling protocols
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