SIP Connected before answer

[jroussy]

SIP Phone 7911G (SIP11.8-4-1S) when call outside show 'Connected' during 'ringing' so I try to see the 'debug voip ccapi inout' but I don't really understand, can someone help me or give me some reference?

[steven.lass]

Is your connection to the PSTN a POTS line?

[jroussy]

Yes, why?

[steven.lass]

An FXS/FXO does not have setup acknowledge, progress indication, and etc. like ISDN and other signaling protocols. The ringing and connect are in-band, so the gateway will send back that is it connected as soon as it grabs the line.

-steve

[jroussy]

In this case why it's work with SCCP phone?

[CHRIS CHARLEBOIS]

I would imagine that the same thing happens with a SCCP phone, except that, when using SIP, the call is 'connected' with the H.323 or MGCP-controlled gateway while it is ringing. With SCCP, the phone only receives call control commands from the Call Manager.

[CHRIS CHARLEBOIS]

Edit: I meant to say "when using SCCP", not "when using SIP".

[jroussy]

So it's normal and I can do nothing to correct that's?

[steven.lass]

That is interesting. I would have expected the callmanager to map the signaling from the MGCP/H323 gateway to the equivalent SCCP and SIP messages.

I was not able to find a solution when I noticed this with an IOS gateway using a SIP trunk to an FXO. Your setup is different.

If you have loop-start FX, "supervisory answer dualtone" in the voice port config may change what is signaled to the callmanager, and possibly ba mapped differently.

Unfortunately, I no longer have any FXO lines in my lab, so I cannot try this myself.

-steve

[jroussy]

Same here, all this, is for one of my customer and in my lab I don't have what it take to test. My client tell me he already test with the command "supervisory answer dualtone" on the voice port of his MGCP gateway but... I would like to test it myself...