[Asterisk-Users] MTU and Voice Delay (latency??)

[Andrew Kohlsmith]

On Tuesday 10 January 2006 17:28, Geoff Manning wrote:
> Just as an update, the users used to be on two 2mb down/512 up ADSL lines
> (PPPoE) (4 users on each) and they never reported a problem. Now that they
> are on one SDSL (PPPoA) line (2mb) is when they report the issues.

Threre are *plenty* of cracked-out ADSL and SDSL modems out there.  I suspect 
the hardware's seeing a ton of tiny packets and trying to be smart about 
handling them, likely by waiting until there is sufficient "traffic" to fill 
its output buffer and then sending the entire buffer.

Also FWIW, at least in North America, ADSL (PPPoE) is actually PPPoA as well; 
any packet you send is being fragmented into dozens of ATM cells and sent 
out, travelling over a multitude of hardware devices which just don't exist 
on the IP layer.

My suspect is the SDSL modem; what is it?  We use ADC Megabit modems here and 
they work fairly well.  We've had some issue with the old Flowpoint 5250s.

-A.