Re: LLQ- help

Here is a great view:

http://www.cisco.com/en/US/docs/ios/12_0t/12_0t7/feature/guide/pqcbwfq.html#wp5329

JS

On Tue, Dec 18, 2012 at 3:28 PM, Marko Milivojevic <markom_at_ipexpert.com>wrote:

> For fun, I added another source of the traffic and lowered bandwidth
> on the interface to 768000 (in an attempt to actually create a
> congestion). This is by no means an exhaustive test of LLQ and the
> quality, but it shows a conditional policer in action.
>
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>
> If you look closely at the pattern of drops above, you will observe
> the regular intervals at which they appear. This *can* be an indicator
> of active traffic conditioner. Let's see what our policy says. Keep in
> mind that the other traffic generator is much more aggressive than the
> first (timeout 0).
>
> ------------------------------8<------------------------------
> R2#show policy-map interface Serial0/2/0 output class PRIORITY
>
> Serial0/2/0
>
> Service-policy output: LLQ
>
> queue stats for all priority classes:
>
> queue limit 64 packets
> (queue depth/total drops/no-buffer drops) 0/0/0
> (pkts output/bytes output) 158281/238054624
>
> Class-map: PRIORITY (match-all)
> 344671 packets, 518385060 bytes
> 30 second offered rate 10173000 bps, drop rate 9649000 bps
> Match: protocol icmp
> Priority: 100 kbps, burst bytes 2500, b/w exceed drops: 186359
> ------------------------------8<------------------------------
>
> The problem is that this test is flawed when it comes to reproducing
> the real congestion, as here we also have to take into account that
> the traffic is arriving from the same input interface, so we have 1:1
> input:output mapping (again, something I mentioned very early in this
> thread as an important factor).
>
> I could spend even more time labbing it up for you, but I suppose I've
> done enough train-the-trainer for one day :-).
>
> --
> Marko Milivojevic - CCIE #18427 (SP R&S)
> Senior CCIE Instructor - IPexpert
>
> On Tue, Dec 18, 2012 at 1:16 PM, Marko Milivojevic <markom_at_ipexpert.com>
> wrote:
> > On Tue, Dec 18, 2012 at 1:14 PM, Narbik Kocharians <narbikk_at_gmail.com>
> wrote:
> >> How did you prove that LLQ kicks in during congestion? How did you
> measure
> >> the quality of these packets?
> >
> > Well, that's not at all what I was testing, as the test was built
> > specifically to avoid congestion to show how there's no policing when
> > congestion does not occur. Apples and Oranges.
> >
> > Testing the quality of these packets would be difficult (not
> > impossible) to measure using IOS-only and Voice SLA probes as traffic
> > generators, but as I said... this was not the point here.
> >
> > --
> > Marko Milivojevic - CCIE #18427 (SP R&S)
> > Senior CCIE Instructor - IPexpert
>
>
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Received on Tue Dec 18 2012 - 16:40:11 ART