[Asterisk-Users] Echo canceller data-points

[Steve Davies]

In case this is useful to someone...

Initially running * 1.0.7 and the default canceller, about 1 in 20 E1
PRI calls still had echo, sometimes quite bad.

Updated to * 1.0.9, and backported KB1 from 1.2 HEAD to this build -
No noticable change over the previous version, but we ran with it
anyway as the small changes in the EC code looked sensible.

Recently we backported MG2 from Zaptel 1.2.4 into our * 1.0.9 build,
and noticed a significant improvement.

I thought I would try the 1.2 trunk/HEAD version of MG2 with the extra
knobs and whistles, but found 2 problems. This version trains even a
normally clean line in about 10 seconds, rather than instantly, and
its CPU usage is through the roof compared to the 1.2.4 version of the
code. (FYI I got very similar resuls at all intermediate SVN versions
of the MG2 canceller between 1.2.4 and HEAD)

My advice: Go with the 1.2.4 MG2 echo canceller, perhaps if you have
plenty of spare CPU the newer code will become useful, but I could not
cancel even 20 PRI channels using a 1GHz processor on the latest code
- I got clicks, buzzing and eventually a dead PRI. With the 1.2.4
branch I had 40% CPU free when cancelling 30 channels.

Hope this helps.

Cheers,
Steve