QOS or more bandwidth

Tue May 29 14:44:19 UTC 2001

On Tue, 29 May 2001, Stephen J. Wilcox wrote:

>> Although I generally agree, how does one keep QoS out
>> of the core for CBR and jitter-sensitive applications?
>
> I would disagree and argue that your core needs to be
> running top of the range routers with fat pipes with
> spare bandwidth, for a large network if you run out of
> CPU or bandwidth your routers will simply fall over.
>
> If you have sufficient bandwidth and your routers are
> running smoothly then there is no use for QoS hence I
> wouldnt use it (plus it will slow down the routing
> process).

QoS isn't just about queueing algorithms and transmit
reordering. QoS-triggered path selection (a la MPLS-TE, PBR)
can be an equally compelling motivation, if the network is
built for differentiated services (which most aren't today,
since a packet is a packet is a packet). This would make
most sense in the core, of course.

Pete.