Hi All, Quick question on what the "correct" behaviour of a SIP redirect server is expected to be, in a Voice Telephony environment where the redirector is used solely to spread call load over a number of dedicated Application Servers:
Initiating AS Redirector Destination AS INVITE-----------------> <-------------100 Trying <-------------180 Ringing * <-------------302 Moved Temp ACK--------------------> INVITE----------------------------------------> <------------------------------------100 Trying <------------------------------------180 Ringing <------------------------------------200 OK ACK-------------------------------------------> Ideally, a SIP Redirect Server should only be implemented with a "limited Transaction User layer, which has access to a location service". You would therefore expect that the server does not act on behalf of the end service (the destination AS has this responsibility), and is only responsible for responding with appropriate level of information about how to reach the end service (via 3xx) or any error handling (4xx). As such, I would expect that there should be no need to send further provisional 1xx responses after a 100 Trying - especially as a 180 is generally used to indicate that the eventual destination has been found, and is being alerted (which is not the case with a redirect server - as the 302 indicates that in fact the end service is still yet to be contacted). So I would then make the assertion that the 180 Ringing indicated by the (*) is in fact superfluous - and I would argue - that it is actually incorrect in a redirect server scenario to implement the stack in this way. Any thoughts? Regards Nathan Smith Senior VoIP Specialist Enterprise Fixed & IP Calling Telstra Corporation Ltd Email: [EMAIL PROTECTED] DISCLAIMER: The information contained in this email message may be confidential. If you are not the intended recipient, any use of, interference with, disclosure or copying of this material is unauthorised and prohibited. If you have received this message in error, please notify me by reply email and then delete the message. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
