[c-nsp] Improved queuing in 12.4(20)T?

[Oliver Boehmer (oboehmer)]

Per Carlson <> wrote on Tuesday, August 26, 2008 10:47 AM:

> Hi.
> 
> I'm doing some QoS-testings and notice a remarkable change in the
> latencies on a priority queue (as well as some improvement on other
> queues) in 12.4(20)T compared with 12.4M (19, 19b and 21) and
> 12.4(15)T7. The scenario is H-QoS with a parent doing "shape average"
> and a child with 4 queues:
[...]

> 
> There *is* a new H-QoS feature in 12.4(20)T called HQF
>
(http://www.cisco.com/en/US/docs/ios/qos/configuration/guide/qos_frhqf_s
upport.html),
> but I can't see that it's directly relevant.

HQF is a totally different QoS infrastructure (previously available on
the 7500/7200 in 12.0S as well as some other trains), so I would assume
this being the reason for the improved behavior.

I haven't looked at HQF for a while, but I recall the H-QoS scenario
you're using benefits especially from HQF as the parent shaper is aware
of the LLQ within the child, but not entirely sure about this. It would
explain the improved behaviour, though.

	oli