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<DIV>Very hard to say without a complete ngrep trace. If both parties are on
public IPs, there is probably something with the signalling, not the SDP
payload. The 183 Session Progress is a so-called provisional reponse. It
can be used for early media (to set up the rtp stream before
connection). A double 183 sounds strange if it's the proxy that does
it.</DIV>
<DIV>g-)</DIV>
<DIV> </DIV>
<DIV>---- Original Message ----<BR>From: Sam Lee<BR>To:
serusers@lists.iptel.org<BR>Sent: Monday, July 25, 2005 12:27 PM<BR>Subject:
[Serusers] 1 way voice issue<BR><BR>> Hi,<BR>> <BR>> I've recently
encountered some problem with my SIP service whereby i<BR>> call out to a
specific number and i encounter a one way voice. If i'm<BR>> the initiator, i
cannot hear the other party but he can hear me. At<BR>> first i thought it
was a return route issue (as i'm going thru NAT) ,<BR>> so i switch my SIP to
a public IP but i still face the same problem.<BR>> Its really only that
specific PSTN number that i have dialed facing<BR>> this problem. The only
difference that i can think of is that PSTN<BR>> number is on a different
route. I did a NGREP from my SIP server for<BR>> the PSTN number that works
(2-way voice) and the Number that doesn't<BR>> work (1-way voice) . The only
difference is there is an extra : <BR>>
<BR>> NGW --> Proxy<BR>> SIP/2.0 183 Session Progress..Via:
SIP/2.0/UDP<BR>> Proxy --> SIP Device<BR>> SIP/2.0 183
Session Progress..Via: SIP/2.0/UDP<BR>> <BR>> <BR>> for the PSTN number
that works (the one with 2-way voice).<BR>> <BR>> Anyone has idea what
does the Session Progress is for ? Or what<BR>> problem am i facing ?
<BR>> <BR>> Thanks a mILLION !<BR>> <BR>> Regards,<BR>>
Sam<BR>> <BR>> <BR>> <BR>>
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