Troubleshooting auto-QoS to protect voice

Hi Guys,

I have an escenario where auto-qos is enabled. The customer has three vlans;
One vlan for voice, one vlan for data and other vlan for wifi.
The problem cames when a virus becomes active and start flooding the
network, in order to use as much bandwith as possible. Then Auto-Qos should
protect and priorize critical traffic, and it doesn't. Checking
configuration I review that traffic is marked in origin, by cisco IP phones,
and the access port is configured to trust DSCP and COS. So at this point we
are sure something is not working when It should.

So a couple of unconfigurations than can cause the problem:
-the layer 2 config vlan for voice, has not being identified as "voice" when
was created, it seems than C2960 with lan base doesn't support this command.

-The connection has a CIR of 10Mb but the interface connection speed
is 100Mb (AR), so it should be a problem when auto-qos is in place? I will
fix it using "srr-queue bandwidth limit 10" under the interface config mode,
is the better way? Can I use auto-qos and also modify some parameters?

How to check it?
-How can I check if some action has been taken in the past? I wish to check
if the last hour the switch has priorized voice over the link.
-By the other hand, how can I check without IP SLA command, because there's
not possible at Catalyst, if the customer lose connectivity and also if
there is jitter problem involved?

Thank you,
Robclav

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Received on Tue Jan 12 2010 - 19:54:26 ART