Hello Vineet Menon,
The 100-trying will be used to stop the timer T1 (500MSEC) , If any subsequent response 18x will take longer than 500msec than 100trying will Be send back to stop the timer T1. Check the timestamp when 180ringing was send. Regards! Valdemar -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of ext Vineet Menon Sent: Wednesday, October 19, 2011 3:06 AM To: [email protected] Subject: [Sip-implementors] sequence of response codes 100 trying Hi, I have a general doubt regarding the sequence of response codes from a proxy. When a proxy receives a request from an UA, say user1 destined to user2, then does proxy always sends back a 100 trying response to user1 before sending a 180 ringing? Or is it that 100 trying is only done in case of forking requests? I will quote the RFC for 100 trying... "This response indicates that the request has been received by the next-hop server and that some unspecified action is being taken on behalf of this call (for example, a database is being consulted). This response, like all other provisional responses, stops retransmissions of an INVITE by a UAC. The 100 (Trying) response is different from other provisional responses, in that it is never forwarded upstream by a stateful proxy." Regards, Vineet Menon _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
