Yes; the RFCs currently require the same transport be used. Some vendors will likely accommodate what you are attempting. However just because the UAC/proxy might be willing to receive the response doesn't mean they will actually process it as you are hoping; thus it might it might be hard to determine "if it is failed".
> -----Original Message----- > From: [email protected] [mailto:sip- > [email protected]] On Behalf Of JC > Sent: Tuesday, June 30, 2009 1:50 AM > To: [email protected] > Subject: [Sip-implementors] About Transport Selection in Response > > Hi All, > > I checked section "18.2.2 Sending Responses" in RFC3261 and section "5 > Server Usage" in RFC 3263, maybe I missed something. My concern is > whether it is mandatory for RESPONSE to use the same transport protocol > as its REQUEST. Needn't think about TLS but UDP/TCP. For example, > incoming REQUEST is "Via: SIP/2.0/UDP", can I use TCP to send its > response. Needn't consider NAT etc. issues. Just wanna make sure SIP > specs don't forbid it. Because sometimes incoming REQUEST is via UDP, > and its RESPONSE takes big message body, can I use TCP to send REPONSE > back. My expecting transport policy in the case is to try TCP firstly, > if it is failed, will have to use UDP to resend mandatorily. > > Thanks and Regards, > JC _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
