[Asterisk-Users] IAX Channel Capacity

[Rich Adamson]

<snip>
> I found a posting by J Todd where he gives BW utilization
> for various IAX2 codecs with trunking on. Now, the number of
> calls I can sustain over an IAX channel, obviously is going
> to be determined by the capacity and state of the physical
> pipe. Typically, here in the office I have a burstable T1.
> The other office has a CIR of 762kbps or such. At the house
> I have ADSL with 128kbps uplink. At some number of calls,
> the channel will collapse. With a PRI, that's not a problem.
> Once all my T1 channels are busy, I get an unavailble, and I
> can inform the caller or take other action. With a IAX
> trunk, I have already observed (at the house) serious
> call/voice deterioration due to channel verload.  How does
> one stop this? I.e. it would be very desirable to specify
> channel capacity (say xx number of simultaneous calls
> allowed) and force an 'unavailable' if more is demanded. 
> Any thoughts on this?

There are not very many ways to handle this realistically. 
You can implement QoS to prioritize your outbound rtp traffic
across the dsl link, but you're still going to be limited to
about two/three calls before quality degrades.

Might consider playing around with implementing some form of
call counter within your dialplan, storing the number using
the DBput function. Then decrementing that value on hangup,
etc. I've not tried this, so I don't have any suggestions as
to what that might look like.