Hello folks, I have a question related to SIP protocol, if anyone knows cause I am a bit confused.
I have an INVITE transaction which contains a Route header as it needs to go through a proxy. The final downstream responds with a non-2xx (480) which is routed back to the initial upstream. My question is whether the ACK (which is a transaction ACK, not a dialog ACK) should contain the initial INVITE's Route headers. I think it shouldn't as this ACK is hop-by hop, but RFC3261 (section 17.1.1.3) says otherwise: "If the INVITE request whose response is being acknowledged had Route header fields, those header fields MUST appear in the ACK. This is to ensure that the ACK can be routed properly through any downstream stateless proxies.". On the other hand, in RFC3665, section 3.11, does not copy the Route headers to the ACK and this is confusing. Seems like RFC3665 is in error, but again to me it seems that appending Route headers in a transaction ACK is pointless, since the final downstream transaction has already been ACK-ed by the middle proxy (like in 3.11 example in RFC3665). So what am I missing here ? Filippos _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
