[asterisk-users] which codec over iax => pstn

[sean darcy]

Atis Lezdins wrote:
............
>>>
>>>> BTW, we have 512kbs over the iax connection.
>>> G711 needs about 80Kb/sec each way to work. (It's 64Kb/sec plus IP
>>> overhead). GSM needs about 32Kb/sec (13Kb/sec plus IP overhead).
>>>
>> So with DSL 512kbs up and 3mbs down, plenty of room for G711.
> 
> Take the weakest link - up 512 kbps, that makes 6 simultenous ulaw
> calls (not counting other traffic). Of course you could push more
> calls, inbound voice would be good (3mbps) but outbound would be
> crappy.
> 
>> Of course, I could figure out how to configure QOS in iptables for
>> asterisk, it'd be a lot better.
> 
> If you have fixed bandwidth, it should be fairly simple, there's some
> ready scripts for scheduling outbound/inbound traffic on fixed
> bandwidth links. This is a very good resource for that -
> http://lartc.org/
> 
> Also i found this yesterday, could be good for start. It doesn't
> assume fixed bandwidth, but just gives priority to VoIP packets.
> http://www.howtoforge.com/voip_qos_traffic_shaping_iproute2_asterisk
> 
That's a great find. I've never been able to figure out the lartc docs. 
This really lays it out, simply. Should be linked from the digium or 
voip-info sites.

> Regards,
> Atis
>