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I am trying to write from the scratch for learning H.323 (without any gatekeeper, straight peer-to-peer).

   public DatagramChannel rtp = null;
   public DatagramSocket socket = null;

But i am not sure which specification i should follow? there are lot of H.323 specs. Has anyone wrote H.323 simple point-to-point apps? Can you suggest which documentation is good to get started for this?

e.g (alas its only SIP, which i tested): http://www.tech-invite.com/Ti-abnf-sdp.html

Thanks

References:

enter image description here

A simple Q.931 message exchange might go as follows: enter image description here

http://wiki.wireshark.org/SampleCaptures (search h323 raw packets)

http://www.en.voipforo.com/H323/H323_example.php

http://xtapi.sourceforge.net/

http://www.eventhelix.com/RealtimeMantra/Telecom/h323_call_flow.pdf

http://www.ccie-wiki.com/H323_Call_Processing.htm

  • Have you tried the [H.323](http://en.wikipedia.org/wiki/H.323) Wikipedia page? it even links to tutorials and information about implementing the protocol – Hasturkun Aug 02 '11 at 14:49
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    "There are a lot of H.323 specs" — no, there aren't. There's exactly one, and it's ITU-T Recommendation H.323. – hobbs Aug 02 '11 at 14:52
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    H.323 is big. And far from simple. You need the specs, available from ITU. At least : [H.323](http://www.itu.int/rec/T-REC-H.323-200912-I/en). [H.225](http://www.itu.int/rec/T-REC-H.225.0-200912-I/en) and [H.245](http://www.itu.int/rec/T-REC-H.245/en) , These will refer you to other relevant specs - you'll at least need to know about ASN.1 and PER encoding. – nos Aug 02 '11 at 15:52

3 Answers3

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If you want to use the RTP (Real time Protocol) protocol in your application in java, i suggest you to find an implementation like this one : http://www.cs.columbia.edu/~hgs/teaching/ais/1998/projects/java_rtp/report.html

It will be easier for you to begin

Dimitri
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  • i mean something like this (exact message details, send/receive packet switchings) e.g: http://www.eventhelix.com/RealtimeMantra/Telecom/h323_call_flow.pdf –  Aug 02 '11 at 14:59
  • Hi, what is your objective exactly? – Dimitri Aug 03 '11 at 08:49
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The definitive source are the ITU specs, but they are pretty hard to read. I would reccommend "IP Telephony: Deploying VoIP Protocols and IMS Infrastructure" by Olivier Hersent as a very good start to learn the protocol.

Gene Vincent
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That's simple: - take two ready made h.323 endpoints, - record the traffic with wireshark. - Look for unclear points in h.323 standards - Mimic the communication

test your endpoints for compatibility

Boris
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