H323 and SCCP in action

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Apr 12th, 2007
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hi there. Any documentation show cisco h323 call/protocol flow diagram and sccp call/protocol flow diagram? and h323 and sccp coexistence call/flow diagram... does cisco support sip? is there any documentation about them too? tx you very much for helps. cheers.

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jemekeren Fri, 04/13/2007 - 00:35
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hi..what ports should be opened to support sccp? does scpp use rtp/rtcp? how rtp flow? is it end to end or end to router then to end? tx :)

thisisshanky Fri, 04/13/2007 - 05:33
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All TCP ports below.

SCCP uses port 2000.

Secure SCCP uses port 2443

H3232 uses port 1720

RTP uses UDP and Cisco phones and devices uses a dynamic range from 16384 to 32767.

RTP flow is between two ip phones if the call is internal to the network. If the call is to a pstn number, then the rtp stream will be directly setup between phone and the voice gateway.



PS: please remember to rate posts!

timothyrand Fri, 10/30/2009 - 11:31
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I am also looking for an SCCP call flow diagram. The link http://www.cisco.com/univercd/cc/td/doc/product/voice/ata/ataadmn/sccp/sccpaaph.htm is somewhat helpful, but it seems to be tailored for the ATA device. Is there a similar document that describes SCCP protocol operation in general - like an RFC? I am looking for something that comprehensively describes *ALL* SCCP messages and there interaction with any end device (but 7962 VOIP phones in particular). Diagrams are helpful too. Thanks in advance

timothyrand Fri, 10/30/2009 - 12:32
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Thanks Brandon. In the first link you sent me, there is a SCCP message called "call state" that goes from the call manager towards the phone. This URL documents the call states http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080624977.shtml Why would the call manager ever send a call state 1 (off hook) to the phone? I would expect the off hook message to always go the other way (from phone to call manager). Can the call manager remotely take a phone off hook? If yes, what is this feature used for? Thanks - Tim

Brandon Buffin Fri, 10/30/2009 - 12:50
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The phone sends an OffHook message to Callmanager indicating that the phone is physically off hook. Callmanager sends a CallState message back to the phone telling the phone what should be on the display, what softkeys to use, etc. The first call state will be Off Hook. After you dial the number you want to call, Callmanager will send a Ring Out CallState message, then a Connected CallState message.

Hope this helps.



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