Cisco ACE Module Packet Drops

[patrik.spiess]

Hi

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

[Daniel Arrondo Ostiz]

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

[patrik.spiess]

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

[Daniel Arrondo Ostiz · Accepted solution]

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

[patrik.spiess]

Ah, now I see.

I guess I'll play a bit with my resource config in the next days ;-)

Thanks

Patrik