The Qos PipeDream [Was: RE: Two Tiered Internet]

Fri Dec 16 09:29:29 UTC 2005

> most large networks (as was said a few times I think) don't really need 
it
> in their cores. I think I've seen a nice presentation regarding the
> queuing delay induced on 'large pipe' networks, basically showing that 
qos
> is pointless if your links are +ds3 and not 100% full. Someone might 
have
> a pointer handy for that?

Here in London, we have noticed that the double-length
bendy buses have a harder time moving through city streets
than motor scooters do. I suspect that the studies you are
referring to show that the key factor is the ratio between
the size of pipe and the size of the flows moving through
that pipe.

> diffserv is the devil... and I think the voip product(s) in question
> aren't meant to be used in places where bandwidth is the constraint :)

A single VoIP call is a rather slim volume of packets compared
to many other uses of the Internet. If a network doesn't have 
systemic jitter caused by layer 2 congestion, then one would 
expect VoIP to work fine on a modern network. Indeed, that is
what Bill Woodcock reported a year or so ago in regard to
INOC-DBA.

--Michael Dillon