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Implementation Notes

On this page, you will find a collection of implementation notes that will help you with various aspects of your work. You may search for notes that are specific to various technologies, including: SIP, SDP, H.323, H.225.0, H.245, ASN.1, RTP, G.723.1, H.264, H.263, and H.324. You may also search the text of the various implementation notes using this search tool. Search engines search the entire site, but we will increase the chances of finding only implementation notes by including the text "+'this article applies' site:packetizer.com" at the front of the search. This will be done for you automatically when you click "Search".

 
  1. Primary and Secondary ISDN Numbers In ARQ And Setup (Q1) {H.323, H.225.0}
  2. Provide E.164 Alias in RRQ (Q2) {H.323, H.225.0}
  3. CNAME Is Not An Email Address (Q3) {H.323, H.225.0, RTCP}
  4. Only Include perCallInfo After Media Received (Q4) {H.323, H.225.0}
  5. User Name in Q.931 Display Information Element (Q5) {H.323, H.225.0}
  6. TPKT Header (Q6) {H.323, H.225.0, T.120}
  7. Multiple RAS Messages Per PDU? (Q7) {H.323, H.225.0}
  8. Whether to Discard RTP Packets with Invalid Packet Types (Q8) {H.323, H.225.0, RTP}
  9. RTP Payload Types (Q9) {H.323, H.225.0, H.245, RTP}
  10. Bandwidth is Bi-directional (Q10) {H.323, H.225.0}
  11. Direction and perCallInfo (Q11) {H.323, H.225.0}
  12. OPTIONAL perCallInfo Fields (Q12) {H.323, H.225.0}
  13. Message-Not-Understood Not Understood (Q13) {H.323, H.225.0}
  14. Whose Address Is In RCF.callSignalAddress? (Q14) {H.323, H.225.0}
  15. Transfer mode (Q15) {H.323, H.225.0}
  16. Ain't It a Bear? (Q16) {H.323, H.225.0}
  17. "Reference value soup" (Q17) {H.323, H.225.0}
  18. Where'd You Come From? (Q18) {H.323, H.225.0}
  19. remoteExtensionAddress (Q19) {H.323, H.225.0, H.320}
  20. timeToLive (Q20) {H.323, H.225.0}
  21. Stayin’ Alive (Q21) {H.323, H.225.0}
  22. Full Response to Lightweight RRQ (Q22) {H.323, H.225.0}
  23. A Design Specification for RAS (Q23) {H.323, H.225.0}
  24. What do the ARJ reject reasons mean? (Q24) {H.323, H.225.0}
  25. Can the GK send IRQ to registered EPs during a call? (Q25) {H.323, H.225.0}
  26. If an EP does not reply to its GK, does the GK unregister it? (Q26) {H.323, H.225.0}
  27. Is there any limit to how many H.245 PDUs can be encapsulated in the h245Control field? (Q27) {H.323, H.225.0, H.245}
  28. What's an h245Address doing in a Setup message? (Q28) {H.323, H.225.0, H.245}
  29. Are fastStart elements, h245Tunneling, and h245Address allowed in a Setup? (Q29) {H.323, H.225.0, H.245}
  30. If an EP supports Fast Connect, does it also need to support H.245? (Q30) {H.323, H.225.0, H.245}
  31. Why do I receive media from some vendors' EPs but not from others'? (Q31) {RTP, RTCP}
  32. From what port does an EP send RTP and RTCP packets? (Q32) {H.323, H.225.0, RTP, RTCP}
  33. Use Presence of Audio, not Packets, to Determine Who Has Floor (Q33) {RTP, G.723.1}
  34. How can one determine the frame boundaries? (Q34) {G.723.1}
  35. Version Interoperability (Q35) {H.323, H.324}
  36. Present Incoming Media ASAP (Q36) {H.324, H.323, RTP}
  37. Relationship Between Packets and Video Frames (Q37) {H.324}
  38. Opening Channel for One-Way Video (Q38) {H.245, H.324}
  39. One Audio Frame Per Packet (Q39) {H.324, G.723.1}
  40. "Say What?" (Q40) {H.323, H.324, H.245}
  41. Don't Forget H.263 SQCIF and H.261 (Q41) {H.324, H.261, H.263}
  42. Always Respond to SendTerminalCapabilitySet (Q42) {H.245}
  43. Always Respond to RoundTripDelayRequest (Q43) {H.245}
  44. Sometimes Not Allowed to Reject RequestMode (Q44) {H.245, H.324}
  45. Support All Signaling Entities (Q45) {H.245, H.324, H.323}
  46. Must Handle Packed SRP Frames (Q46) {H.324, H.245}
  47. Must Transmit DTMF (Q47) {H.323, H.324, H.245}
  48. Must Accept Silence Frames (Q48) {H.324, G.723.1}
  49. Modem-Specific Issues (Q49) {H.324}
  50. Choking the Multiplexer (Q50) {H.324}
  51. Clarification of H.245 MTSE (Q51) {H.245, H.324}
  52. Disambiguating Unconstrained OPTIONAL Components in H.245 (Q52) {H.245}
  53. G.723.1 Framing (Q53) {H.245, G.723.1}
  54. Abide by Framing in Audio Caps (Q54) {H.323, H.225.0, H.245, G.711, G.723.1}
  55. Which G.723.1 Bit Rate? (Q55) {H.245, G.723.1, RTP}
  56. Capability Descriptors (Q56) {H.245}
  57. One RTDSE Per Call, not Terminal (Q57) {H.245}
  58. Closing Channels (Q58) {H.323, H.324, H.245}
  59. Commands Are Just That (Q59) {H.245}
  60. Obey Speed Limits (Q60) {H.245}
  61. Mode is a Set of Streams (Q61) {H.245}
  62. Decoding H.245 ASN.1 Extension Additions (Q62) {H.245, X.691}
  63. Signaling Temporal/Spatial Tradeoff in H.245 (Q63) {H.245, H.323, H.324}
  64. H.221 Non-standard Codepoints (Q64) {H.245, H.225.0}
  65. Changing Capabilities During a Call (Q65) {H.245}
  66. A Problem with CommunicationModeCommand (Q66) {H.245, G.723.1}
  67. CommunicationModeCommand versus RequestMode versus TerminalCapabilitySet (Q67) {H.245}
  68. Video Format Signaled In-band (Q68) {H.245}
  69. What's a portNumber For? (Q69) {H.245, H.323, H.324}
  70. What do I set sessionId and associatedSessionId to? (Q70) {H.245}
  71. What Happens When Both EPs Start Capability Exchange At The Same Time? (Q71) {H.245}
  72. terminalCapabilitySet Is a Delta (Q72) {H.245}
  73. Must Both EPs Perform Master Slave Determination? (Q73) {H.245, H.323, H.324}
  74. Why is Master Slave Determination Acknowledged In Both Direction? (Q74) {H.245}
  75. What Audio Packetization Should I Specify When Opening a Channel? (Q75) {H.245}
  76. How Many Audio What's Per What? (Q76) {H.245, G.711, G.723.1, G.729, H.225.0, H.223}
  77. What is the relationship between the CapabilityTableEntryNumber and the CapabilityDescriptorNumber in H.245? (Q77) {H.245}
  78. Are capabilities in the capabilityTable field of TerminalCapabilitySet listed in order of preference? (Q78) {H.245}
  79. Are simultaneous capabilities listed in order of preference? (Q79) {H.245}
  80. How can one indicate symmetric codecs? (Q80) {H.245}
  81. Why do I have to retain the value of a timer I reset? (Q81) {H.245}
  82. LRJ reject reason, notRegistered (Q82) {H.323, H.225.0}
  83. Does an endpoint have to use a gatekeeper? (Q83) {H.323, H.225.0}
  84. If a field is marked OPTIONAL, do I have to encode it? (Q84) {X.691, H.245, H.323}
  85. Does a gatekeeper participate in MSD? (Q85) {H.323, H.245}
  86. Only one G.723.1 frame per packet? (Q86) {H.323, H.225.0, G.723.1}
  87. What is the well-known port for H.245? (Q87) {H.323, H.245}
  88. Call flow for third-party pause (Q88) {H.323, H.245}
  89. How do I know if the other endpoint will honor my TCS=0? (Q89) {H.323, H.245}
  90. Flow Control (Q90) {H.323, H.225.0, RTP}
  91. Both Rates of G.723.1 (Q91) {H.323, G.723.1, H.245}
  92. Prudent to Support G.723.1 (Q92) {H.323, G.723.1, G.729}
  93. Don't Forget G.711 (Q93) {H.323, G.711, H.245}
  94. Don't Forget H.261 (Q94) {H.323, H.261, H.263}
  95. Always Respond to SendTerminalCapabilitySet (Q95) {H.323, H.245}
  96. Always Respond to RoundTripDelayRequest (Q96) {H.323, H.245}
  97. Sometimes Not Allowed to Reject RequestMode (Q97) {H.323, H.245}
  98. First H.245 Message Transmitted (Q98) {H.323, H.245}
  99. Interoperability and Compliance Rant (Q99) {H.323}
  100. Termination of Call by GK (Q100) {H.323, H.225.0}
  101. Registering a Zillion Aliases (Q101) {H.323, H.225.0}
  102. GK As a "Version GW" (Q102) {H.323, H.225.0}
  103. H.323 Taxonomy (Q103) {H.323}
  104. Call Termination (Q104) {H.323, H.225.0, H.245}
  105. H.323, H.225.0, and H.245 Versions (Q105) {H.323, H.225.0, H.245}
  106. What versions are interoperable with what other versions? (Q106) {H.323}
  107. How will I know which decoder to use if I use alternative media in Fast Connect? (Q107) {H.323, H.225.0}
  108. Does an H.323 EP have to support H.245? (Q108) {H.323, H.245}
  109. Is it possible to develop an H.323 stack in Java? (Q109) {H.323}
  110. Where is the format of H.323 messages described? (Q110) {H.323, X.691, H.245, H.225.0}
  111. Encoding Fast Connect OLCs (Q111) {H.323, H.245, H.225.0}
  112. Maintenance Loops (Q112) {H.245, H.323, H.324}
  113. For what are the prefixes in SupportedProtocols used? (Q113) {H.323, H.225.0}
  114. What is the format of the Cause IE? (Q114) {H.323, H.225.0}
  115. ASN.1 PER Implementation Guidelines (Q115) {ASN.1 PER, X.691, H.323, H.245, H.225.0}
  116. UserInputSupportedIndication (Q116) {H.323, H.324, H.245}
  117. H.264 Support in H.323 (Q117) {H.323, H.245, H.264}
  118. Setting the Call Reference Value (CRV) Flag (Q118) {H.323, H.225.0, Q.931}
  119. Protocol Port Numbers (Q119) {H.323, H.225.0, SIP, MGCP, H.248}
  120. Comparing Status Determination Numbers when Negotiating Master/Slave in H.245 (Q120) {H.323, H.245}
  121. DiffServ values for VoIP and Videoconferencing (Q121) {SIP, H.323, H.248, MGCP}
  122. SIP OPTIONS "Ping" (Q122) {SIP, POCS-1}
  123. Video Resolutions Used in Videoconferencing and Video Streaming (Q123) {H.320, H.323, H.325, SIP, RTP}