________________________________________
From: [email protected]
[[email protected]] On Behalf Of Peter
An incoming call is first ringing on a call center queue:
The UAS is sending a 180 Ringing with SDP and a require: 100rel, the UAC
responds with a PRACK and the UAS again with an 200 OK.
Then the call is actually ringing on a UA (IP hardphone)
The UAS send a 180 Ringing again with an SDP and a require:100rel, but
the UAC ignores this as is seems a duplicate message.
<--
INVITE/SDP supported: 100rel
100 Trying -->
180 Ringing/SDP -->
Require: 100rel RSeq:1
<-- PRACK
200 OK -->
180 Ringing/SDP -->
Require: 100rel RSeq:2
180 Ringing/SDP -->
Require: 100rel RSeq:2
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I can't imagine why the UAS sends the 3rd and 4th 180 responses -- it has
already confirmed the dialog with the 200. I'm not sure if "late" provisional
responses are forbidden by any specification, but I would not be surprised if
the UAC does not pay any attention to them.
Dale
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