Codecs bandwidth limit

Hi, I’ve run into the following issue
My ISP provides with IP telephony as well, and they only allow two codecs, alaw and g729, since g729 needs a license we will stick with alaw for now, so the question is this:

Is there a way to change the quality of alaw to lower the bandwidth consumption?

I’ve tried setting the parameters in codecs.conf like this:

[alaw] quality => 4 complexity => 3 enhancement => true vad => false vbr => false abr => 8000 vbr_quality => 5 dtx => false

But that doesn’t seems to work at all…

Thanks in advance


A licence is $10 per channel. You dont need to spend long trying to do the impossible to make the cost of the licence seem cheap.
If bandwith is an issue stump up the money.


these days bandwidth is cheaper than CPU processing power. g729 is bad for us/canada calls. I don’t understand why there aren’t more providers supporting iLBC instead of g729. It’s more stable under high jitter and doesn’t require a license. Hate those cisco switch. viva asterisk.

Thanx for your replies

We finally ended using iLBC for calls originating from our server, but when we receive a call it’s alaw, so 50% of the problem was solved :laughing:

Hi You hae got me confused here. You said your supplier only suported G711 and G729, But you now say they seem to support ilbc. which is fine on decent hardware but can introduce delays on older hardware.
Have you tried using any other codecs with them? It looks as if they support more than they say.


Yes, I’m a little confused myself, but yesterday we started to try different codecs, the provider told me they only support G729 and Alaw, but we started trying one by one all codecs.
We were able to connect with iLBC and alaw only, I really don’t know why, but it worked.

Probably the guy at the phone didn’t know much about IP telephony nor codecs…