On Tuesday 03 August 2004 19:44, Chris Shaw wrote: > > QoS isn't going to help you get to talk in a crowded CSMA/CD network. > > I might be misunderstanding you about QoS, but I know for a fact that it > does help greatly because whether you use DSL or Cable, your bridge device > (it's not a modem no matter how much people want to call it that, it's a > bridge!) uses large buffered queues to achieve sustained transfer rates... > this is awesome for bulk downloads but makes your VoIP conversation sound > like you're on a cellphone under a bridge in a windstorm... Also if the ISP > is using QoS and they classify users by the MAC address of your bridge > device, they can create something similar to ATM PVCs, allowing traffic to > flow more orderly and evenly across THEIR network...
What I am saying is that you are shaping your ethernet to your cable modem (and yes I call it a cable MODEM -- you're still modulating and demodulating -- it's just DMT or some superhypermega modulation method) -- once it hits your cable modem you're playing the CSMA/CD game and if you collide you're SOL, there goes your timely packet. And yes I know all about huge queues... The cure for that (at least with DSL) is to get a Sangoma S518 -- it's a PCI ADSL modem with drivers for everything... I just prioritise packets now (no rate limiting) and get my full 4M/800kbit without any nonsense. I can flood the link in both directions and my VOIP sounds perfect. You just can't do that with an external modem -- tested 3 different ones (Speedstream one that comes with Bell HSE, an "industrial" grade one that comes with commercial DSL and also an old FP2100 -- the Bell one was by far the worst -- I had to rate limit to 400kbps or it would start queueing up the packets like crazy. > Bear in mind that when you're using QoS you're shaping YOUR traffic as it > goes out YOUR link... you can do nothing about what happens to it once it > crosses your ISP's router into the rest of the InterNet. Exactly -- you're shaping your upstream and with a busy CSMA/CD or CA network you won't have much luck since your prioritised packets are getting delayed on their way to the head unit. -A. _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
