[OpenSIPS-Users] opensips-cp CDR correlation

[Iñaki Baz Castillo]

El Miércoles, 29 de Abril de 2009, Dan Pascu escribió:

> You realize that a B2BUA completely separates the 2 call legs, which
> includes audio.

I mean "SIP transparent B2BUA" which doesn't handle media and doesn't touch 
the SDP at all.


> If you only attempt to split the signaling path, but leave
> the media path to flow directly, you may have trouble with NAT.

For that I have a proxy calling a media-proxy when needed, but if both users 
are behind the same NATm using the media-proxy is not required (and this is 
the example I described).


> So if you
> replace a media relay with a B2BUA which does media transcoding, I do not
> believe you are any better.

I've never told about B2BUA with media transcoding.


> > Imagine a company using a hosted virtual PBX solution (the
> > proxy/SA/B2BUA has public IP while the phones are behind NAT).
> > Imagine the boss wishing to have an accurated log (cdr) of how long
> > his employers are speaking between them. These calls take place,
> > probably, into the same LAN so a media-proxy is not required to allow
> > bidirectional audio.
>
> It may not be required, but it can be used to get some additional
> benefits, even more in this particular example, considering that LAN
> traffic is cheap.

LAN traffic is cheap? perhaps I should describe again the scenario I 
described:

A company using a *hosted* virtual proxy/PBX service. The provider (the 
proxy/B2BUA is in some datacenter while the phones are in the company office 
behind a NAT router). There is no media-proxy in the LAN. If you force a 
media-proxy it should take place out of the office (so comsuming 
ADSL/SHDSL/... bandwith).


> > Also, forcing a media-proxy could consume high bandwitch and create
> > audio delay.
>
> This is actually incorrect. A media relay should be positioned next to the
> PSTN gateway, so that the network will not see more traffic than it would
> have seen if the media streams would have reached the gateway directly.

In my example, I clearly spoke about a conversation between two phones in the 
LAN.
With your suggestion (using a media-proxy to ensure the accounting 
reliability) the audio would go and back to the provider datacenter (in which 
the media-proxy resides).


Regards.



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