[e2e] Skype and congestion collapse.

[Cannara]

On where congestion is occurring today in the Inet, it would be useful to ask
Les Cottrell at SLAC how things have been going with their continued
"ping-around-the-world" testing.  It had been true that busy peering points in
the East & West of the US commonly lost 30%.

Alex

RJ Atkinson wrote:
> 
> On Mar 4, 2005, at 17:47, Clark Gaylord wrote:
> > This is why we really do need some notion of QoS other than The Fat
> > Pipe.  It doesn't have to be as elaborate as RSVP-disciplined CAC, but
> > you need to be able to prioritize traffic that matters and limit the
> > amount of traffic that gets prioritized.  It doesn't have to be more
> > complex than that, but it has to do at least that.  [Ergo ... left as
> > an exercise to the reader.]
> 
> I don't know that the "network" needs to have a more sophisticated
> notion
> of QoS than best effort.  It can sometimes be useful for the network
> device
> connected directly to a congested link (e.g. access link between a site
> and
> its upstream provider) to have some internal-to-the-box QoS
> configuration.
> 
> It is not uncommon these days for the access router at the customer
> premise
> to have some ACL ruleset that prefers some traffic over other traffic or
> rate-limits certain kinds of traffic -- and equivalent configuration of
> the aggregation router on the ISP side of the same link is also not
> uncommon these days.
> 
> That said, most congestion today occurs either on an access link such as
> that or on some sort of wireless link (e.g. SATCOM to SW Asia).  ISP
> core
> backbones tend to be over-provisioned.  Most campus (wired/fibred)
> networks
> are similarly over-provisioned.
> 
> Ran