[c-nsp] QoS - questions

[Tim Franklin]

On Tue, August 21, 2007 12:26 pm, Oliver Boehmer \(oboehmer\) wrote:

> Thanks for your input, made me look at the MQC specs again (and will
> have to revise my statement made earlier.. guess I'm getting old ;-)

Hehe - if engineers aged every time our first answers weren't spot on, I
think we'd all be in homes by now :)

> the tocken bucket configured within the "priority" command is used to
> tell if the router needs to guarantee low-latency for the packets. If
> the traffic rate exceeds the configured rate, it will be sent right away
> if the link is uncongested at the time of excess traffic arrival, and
> will be dropped otherwise. I guess how this is exactly being implemented
> is somewhat platform/queuing-infrastructure-dependant..

OK, thanks.

> Either way: You don't want to send more LLQ traffic than configured
> there, otherwise you *might* drop packets.
>
> priority without any cir/bw argument can result in all bandwidth being
> used by this class, so a policer confirmed in addition (the 2nd example
> above) would unconditionally drop packets above the configured policer's
> rate.

Agreed on both points - and this is where I'm trying to get to, but I need
to be able to explain what it's doing now, why this is not the best of
ideas, and what we really need to make it act like it best ought to.  Plus
work out what the marketing docs say when they say we're selling 'QoS'...

Thanks for the clarification,
Tim.