[SIPForum-discussion] 183 Session Progress

sunilkumar.verma at wipro.com sunilkumar.verma at wipro.com
Fri Jan 22 03:44:11 UTC 2010



It is not mandatory for the far end to see 100 Rel to generate 183
session Progress response.

If we go as per RFC there is no such limitation for generating 180 or
183 or any 1XX response apart from 100 Trying.

But in most of the scenario 183 is sent to indicate the far end that the
call is in progress before the call land on actual user to ring, which
generate 180 ringing. 


Require: 100rel is used if we need acknowledgement of provisional
response in "Prack". Generally its used to reset the timer at proxy
which will terminate the transaction if the 1XX response after100 trying
is not sent in certain time limit (which I remember is 3 minutes).



Sunil verma


From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of SIP Babie
Sent: Wednesday, January 20, 2010 1:26 PM
To: discussion at sipforum.org
Subject: [SIPForum-discussion] 183 Session Progress


Hi All,

Please let me know when the provisional response  "183 Session Progress"
is been sent as a reply of INVITE.
Does Outbound Proxy looks for some header in INVITE on the basis of
which it sends "183 Session Progress" provisional response, like 100rel
support in INVITE. 

SIP Babie

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