[SR-Users] A question to you, SIP providers: what is your policy on PBXes calling themselves

[Klaus Darilion]

Am 07.06.2015 um 05:06 schrieb Antonio Gómez Soto:
> Hello,
>
> This is question on PBX behavior, what is the right thing to do, and how
> do PBX's generally behave.
>
> If a user on a phone, dials a number, which happens to be configured on
> the same phone system (for example another tenant), there are two options:
>
>  1. The PBX notices this, and directly connects the phone to the DID on
>     that system (breaking separation of tenants)
>  2. The PBX sends the call out on the SIP trunk, and the
>     provider-routing sends the call back as an incoming call.
>
> What are the pros and cons of each option from the SIP provider point of
> view?
> How do PBX's generally behave?
>
> Thanks,
> Antonio

(a bit late but maybe still interesting)
I always keep the call local to my environment, but not local to a 
single PBX. E.g:



PBX1---\
         \
PBX2----GW----- TRUNK ------------- PSTN-Provider
         /
PBX3---/


Calls which are internally to a customer stay on the PBX (as these are 
not charged usually).

Calls between my customers are always routed to my "Gateway", which 
decides the routing, e.g. sends the call back to the same PBX or some 
other PBX (for local DIDs) or to the PSTN termination provider.

This way I always have the same routing and CDRs regardless if the user 
is on the same PBX or some other. For billing I only use the CDRs 
generated by the "Gateway" SIP server (I use Asterisk).

In a small setup this may seem a bit complicated. But you soon may have 
multiple PBX servers (lots of customers, different PBX software versions 
....).

regards
Klaus