On Thursday 04 May 2006 14:43, Tony Davis wrote: > I am getting a number of complaints from the folks in my company wrt > voice quality. We have a standard (?) Allstream T1 with 12 users and a > simple Linksys WRT54GS router. It has some basic QOS settings which I
I'm assuming that the Allstream T1 is for voice, not data. Is this correct? > have configured. I am using Polycom phones and my voip service provider > is unlimitel so all the equipment and services should be ok. The quality > issues are not consistent and occur periodically. They are best > described as popping and clicking and broken (especially outbound) > speech. Who's your connection through? Are you using a craptastic ADSL modem (the ones Bell likes to ship are JUNK)? > My suspicion is that it's a QOS issue and so I am looking for a good QOS > router that people have had experience with. Any other ideas relating to > improving the quality would also help. I use a Sangoma S518 PCI ADSL modem. It's an internal card with linux drivers and excellent support from the Sangoma folks. I use this card because I can use a standard run-of-the-mill Linux box with my amazing, does-it-all, glow in the dark, effervescent rc.tc script which allows me to TOTALLY PEG the uplink to 800kbps without so much as a warble in my outgoing voice quality. You can't do that with external modems because once the ethernet frame is in its grubby little mitts it can do whatever it wants, and 90% of the time it will "hold on" to the packet and send a bunch of them in a burst in a lame attempt at increased performance. With the S518 the packet queues are firmly in the kernels clutches and the QoS script of Doom affords me all of the control I need. If you're flooding your downstream the script will help with that, but you really do need to either use traffic shaping/QoS at both ends of the link or just pray you can kind of "push on a rope" and control it all from one side. I can explain in more detail if you like. Anyway: get it now, at http://www.mixdown.ca/~andrew/dump/rc.tc. It's based off of the wondershaper script, but modified quite a bit from the original. It will need some tweaking for your particular system, but once configured for you it should work very well. I know it works very, very well for me in the various places I've used it. It will help even those poop Speedstream modems Bell hands out, but you will find you have to limit your uplink to about 50% of the actual capacity in order to keep the modem from playing silly bugger with your voice traffic. If that T1 is really for your data, get one of the Sangoma T1 cards (A101u?) and keep the connection as much under the kernel's control as possible. The second you hand your data off to some external device you are at its mercy, and Murphy and his laws are still very much alive and well in these devices, as you've experienced. -A.
