North American Network Operators Group|
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical
Re: The Qos PipeDream [Was: RE: Two Tiered Internet]
Thus spake "Mikael Abrahamsson" <firstname.lastname@example.org>
There's two problems, actually. The first is serialization delay, and afflicts any link under about 3Mb/s regardless of utilization. Access speeds are finally climbing past this, but for links where they haven't you need something like MLPPP for fragmentation and interleaving.On Fri, 16 Dec 2005, Christopher L. Morrow wrote:ah-ha! and here I thought they wanted buzzword compliance :) From what sales/customers say it seems like they have a perception that 'qos will let me use MORE of my too-small pipe' (or not spend as fast on more pipe) more than anything else.
The second is queueing delay, and that tends to only matter when average utilization passes 58% (someone with a stat background explained why, but my math isn't good enough to explain it). LLQ and WRED solve this well enough for end systems to cope with the result.
So combining voip and data traffic on a link that sometimes (more often now when windows machine have a decent TCP window) go full, evenAdaptive jitter buffers are old technology; Skype is hardly the first company to use them. Most phones and softphones have them; it's the gateways at the other end that are usually stuck with static ones.
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking