[Asterisk-Users] reliable capacity for a single * box

[Dorn Hetzel]

I have a couple of capacity related questions for which I am hoping
to find answers (or at least hints) derived from real-world experience.

    asterisk as a "trunking gateway";  bunch of sip phones in location
    one need to access other non-* sip PBX device in location two over
    constrained bandwidth.  I can't replace the existing SIP phones or
    the other SIP device.  I'm considering using * boxes at each end of
    the WAN circuit to pack all of the individual SIP sessions into an
    IAX2 trunk and then unpack them back into SIP at the far end.

    Assuming for the moment G.711 all the way thru, so no codec 
    conversions anywhere, how many simultaneous sessions should
    I reasonably expect to get through a typical single CPU P4 3.2ghz
    box?

    Then as an option, if I wanted to compress the SIP G.711 calls
    into say IAX2-GSM trunks, how would that impact the channels per
    box number?  (well, I know it's going to go down, any hints how
    much?)

Any thoughts?

Regards,

-Dorn