[OpenSIPS-Users] opensips-cp CDR correlation

[Iñaki Baz Castillo]

2009/4/30 Adrian Georgescu <ag at ag-projects.com>:
> The more load you have at some moment in time you need to add more servers.
> The curent design allows MP2 to handle several thousands of simultaneous
> sessions. Anyway, far from trying to advocate its load capabilities the
> question we all try to find the answer for is:
>
> With a media relay in the path the accounting works deterministically
> regardless of SIP client behaviour with the penalty of bandwidth utilization
> in the relay location. Do you have another solution that works reliable and
> deterministically in any case (again 100% success) without it?

As I've already explained before:

Using a SIP transparent B2BUA (instead or behind a proxy) which
performs SST on both legs and does accounting when SST expires in some
leg or when it receives a correct BYE.
A B2BUA is not vulnerable as a SIP proxy. If a B2BUA receives a BYE it
won't route it based on the BYE headers/RURI (risk!!!), instead it
will generate a new BYE for the other leg => the gateway. Any spoofed
BYE sent by an attacker just could get:
a) The B2BUA consideres this BYE as invalid so:
  a.1) The BYE is rejected with "400 XXX" and the call remains active.
  a.2) The B2BUA detects some attack and decides to terminates the
call (does acc and sends BYE to gateway).
b)  The B2BUA consideres this BYE as valid so terminates the call
(does acc and sends BYE to gateway).

PD: No, I've not this scenario working, it's just theory.


-- 
Iñaki Baz Castillo
<ibc at aliax.net>