[Serusers] About a SIP load balancing document involving SER

[Victor Pascual Ávila]

On Wed, Oct 8, 2008 at 11:41 PM, Iñaki Baz Castillo <ibc at 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,
-- 
Victor Pascual Ávila