Bandwidth Overhead of IAX2

Is there a rough guess, how much bandwidth overhead IAX2 creates ?
I need to estimate the bandwidth requirement for the internet connection of 2 * connected via IAX, assuming 10 simultaneous channels, for instance.
The use of IAX2 will need some bandwidth, on top of the bandwidth necessary for the 10 active channels, I suppose. Is it possible, to give a rough guess of the overhead, as a percentage value ?
Or is there even a positive effect, because of better packetising, for instance ?

Hi

I think this is what you are looking for

voip-info.org/wiki/view/Aste … width+iax2

Ian