> 1) If we can not send the response in TCP, > then how we can send the response.
As others have mentioned, rfc3261 section 18.1.1 discusses that UDP fragmentation will occur for SIP messages over (approximately) 1300 bytes. And implementations MUST be able to handle 65k byte SIP messages sent over UDP. Thus assuming your response isn't over 65k bytes, you should send the response over UDP. However because of fragmentation, it might take a few retries to get the response successful delivered. > 2 ) if we have to send Failure response, > then what response code we have to use ? There currently is not a SIP response that clearly indicates that the request was successfully received but please resend it over a different transport. For requests outside of a dialog, returning a 3xx response with a Contact entry indicating the desired transport might work if the device acting upon the redirection supports the transport and is willing to use it. For requests within a dialog, the endpoints can temporarily switch transports. For instance a request can be rejected with a failure response (like 500) with a retry-after. The device can send an UPDATE or re-INVITE with a Contact indicating the needed transport. If the device honored the retry-after, the request will be sent over the updated transport when the retry-after expires. _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
