28 Feb
2005
28 Feb
'05
11:43 p.m.
Hey Steve,
The reason you don't see the REFER is because it wont be sent until
after the re-INVITE is responded to. The idea here is that you are going
to "flash" to a new line or use the Conf/Join buttons on the Cisco
phones which means that the session must be modified before the REFER
can be sent. In your case the re-INVITE will modify the ports and media
parameters in the session and will (usually) move the call from sendrecv
to sendonly state (check the a= tags in the SDP) it will also specify
new parameters in the m= tag in the SDP. The GW needs to respond with a
200 OK before your UA will send a REFER message.
-Evan
On Mon, 2005-02-28 at 16:37 -0500, Steve Blair wrote:
Thanks. The odd thing is I never see the REFER using
ngrep. Any idea why?
Evan Borgstrom wrote:
>Hey Steve,
>
> The INVITE's you're seeing are re-INVITES. They're used to modify the
>session before the Cisco phone sends the REFER to transfer the call.
>Check out Section 14 of the SIP RFC (3261).
>
>http://www.faqs.org/rfcs/rfc3261.html
>
>-Evan
>
>On Mon, 2005-02-28 at 16:09 -0500, Steve Blair wrote:
>
>
>> I'm a bit stuck and wonder if someone on this list can help.
>>When a call arrives at a Cisco IP phone registered to our
>>SER proxy from the PSTN it is answered. The called party
>>then tries to transfer the call. In either case a new invite is
>>generated. I'm under the impression a refer message should be
>>generated but given the way attended transfer works on the
>>7960s it doesn't seem possible to have a refer generated. Has
>>anyone else seen this? If so any thoughts on what is happening?
>>
>>Thanks,Steve
>>
>>_______________________________________________
>>Serusers mailing list
>>serusers(a)lists.iptel.org
>>http://lists.iptel.org/mailman/listinfo/serusers
>>
>>
>
>
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