[e2e] Skype and congestion collapse.

[RJ Atkinson]

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