On Wed, Oct 8, 2008 at 11:41 PM, Iñaki Baz Castillo ibc@aliax.net wrote:
El Miércoles, 8 de Octubre de 2008, Victor Pascual Ávila escribió:
Actually I understand this document to be part of a research project. I don't believe that ignoring a VIA header or preventing a SIP entity from inserting a VIA header is a common praxis in the industry. But as you might imagine, research is research and prototypes are prototypes
Well, however this is completely unfeasible since it would involve modifying all the SIP devices to be compliant with this non RFC3261 specification.
I'm afraid I don't agree here: one could use a transparent B2BUA (i.e. B2BUA used as a Proxy Server). The B2BUA would copy the message from the inbound leg to the outbound leg and could modify the VIA header-- yes, it is not really elegant but still feasible.
Also, it's a completely crazy idea. What to do in the following scenarios?
a) UAC --- (udp) --> LB proxy -- (tcp) --> UAS
b) UAC --- (tcp) --> LB proxy -- (udp) --> UAS
Note that replies for a transaction must use the same network transport, so it's just impossible that UAS in case a) (who receives the request via TCP from proxy) to reply UAC directly using UDP.
I think we already had this discussion in sip-implementors. Anyway, in this scenario, I consider the LB to act as a simple dispatcher and not as a "transport converter". But you are right.
Thanks for your comments,