topic Cisco ACE Module Packet Drops in Application Networking

Cisco ACE Module Packet Drops

patrik.spiess — Fri, 07 Oct 2011 09:33:25 GMT

During high throughput times (nightly, when backup runs) we see packet drops on the network. We think it's the ACE module that drops. We use 2 ACE20-MOD-K9 with base licenses in a FT configuration in Layer2 Mode.

Now I found an interesting statistic on the ACE:

uzhlbsrv1/Admin# sh resource usage resource rate bandwidth

Allocation

Resource Current Peak Min Max Denied

-------------------------------------------------------------------------------

Context: Admin

bandwidth 374 4579 27437502 151187502 0

Context: NOZONE

bandwidth 0 3914 49875004 173625004 0

Context: ZONE1

bandwidth 13177316 274336969 49875004 398062508 4289696988

Context: ZONE2

bandwidth 204178 69633779 49875004 398062508 0

Context: ZONE3

bandwidth 4994 67204248 49875004 398062508 0

Context: ZONE4

bandwidth 0 2276 49875004 398062508 0

Does anyone knows what exaclty the 'Denied' column means?

Especcially because we have a lot of them on context ZONE1.

If I calculate the value to Gbps it is 34,371Gbps (gigabit per seconds)

Does anybody know how to reset this counter?

Thanks

Patrik

Cisco ACE Module Packet Drops

Daniel Arrondo Ostiz — Mon, 10 Oct 2011 09:44:38 GMT

Hi Patrik,

The "Denied" counter indicates packets that were dropped because the bandwidth over what was available to the context. Take into account that, if a context has a minimum value configured, then, this value will be reserved and not available for other contexts, so, you may not be able to reach the configured maximum.

I would recommend you to check if this counter increases at the time of the issue, and if so, review the resource allocation policy.

To clear the counters, you can use the "clear stats resource-usage" command

Regards

Daniel

Cisco ACE Module Packet Drops

patrik.spiess — Mon, 10 Oct 2011 10:03:06 GMT

Hi Daniel

I was in fear that these denies come from too low bandwidth.

Unfortunately "clear stats resource-usage" does not clear the denied counters:

uzhlbsrv1/Admin# sh resource usage context ZONE1 resource rate bandwidth

Allocation

Resource Current Peak Min Max Denied

-------------------------------------------------------------------------------

Context: ZONE1

bandwidth 22265761 274336994 99875000 673062504 32609986

uzhlbsrv1/Admin#

uzhlbsrv1/Admin# clear stats resource-usage

uzhlbsrv1/Admin#

uzhlbsrv1/Admin# sh resource usage context ZONE1 resource rate bandwidth

Allocation

Resource Current Peak Min Max Denied

-------------------------------------------------------------------------------

Context: ZONE1

bandwidth 11654624 274336994 99875000 673062504 32609986

We allocated a maximum of 100% to this resource. So I guess only way is to upgrade the bandwidth license ond the ACE?

bandwidth 4.44% 5.00% RESOURCE_CLASS_ADMIN

8.88% 10.00% RESOURCE_CLASS_NOZONE

8.88% 100.00% RESOURCE_CLASS_ZONE1

8.88% 100.00% RESOURCE_CLASS_ZONE2

8.88% 100.00% RESOURCE_CLASS_ZONE3

8.88% 100.00% RESOURCE_CLASS_ZONE4

thanks & regards

Patrik

Cisco ACE Module Packet Drops

Daniel Arrondo Ostiz — Mon, 10 Oct 2011 10:12:43 GMT

Hi Patrik,

You may not need to increase the license.

Right now, you have allocated almost 50% of the total resources to the minimum allocations of the contexts. As I mentioned earlier, these resources are reserved and cannot be used by another context.

Before upgrading the license, I would recommend you to reduce (or remove) the minimum resource allocation for all the contexts (except Admin) and see if this makes a difference.

Daniel

Cisco ACE Module Packet Drops

patrik.spiess — Mon, 10 Oct 2011 10:19:20 GMT

Ah, now I see.

I guess I'll play a bit with my resource config in the next days 😉

Thanks

Patrik