[OpenSIPS-Users] opensips-cp CDR correlation

[Dan Pascu]

On Thursday 30 April 2009, Iñaki Baz Castillo wrote:
> Yes, I agree on it. However I just wanted to mean that using a
> media-proxy is not the best solution for all the cases, specially when
> clients are behind same NAT (an office for example) and the PBX/Proxy
> is hosted in some datacenter.

There is no reliable way to detect if 2 devices are in the same LAN behind 
NAT.

> Also, for calls to a gateway in our same datacenter, forcing the RTP
> through a media-proxy is not the only solution. Using SessionTimers
> (so a B2BUA is required and not just a proxy) is also a good solution
> (and cheaper since no servers are needed for relaying the media).

That is not actually accurate. No _new_ servers are needed, as in you can 
reuse any existing server for this purpose. Nowadays mediaproxy is very 
efficient because it uses conntrack rules in the kernel to forward the 
packets. It does forward hundreds of media streams with virtually no load 
on the CPU, so you can reuse your SIP proxy server to run it. It just adds 
an indirection point between the UAC and the gateway without increasing 
the network traffic and the benefits greatly overcome the inconveniences 
as you get accuracy down to the second in accounting and do not care about 
SIP level hacking attempts.

-- 
Dan