Cisco 4000 - K2CPU Review Analyse

[NICOLAS GERVY]

Hi,

Sometimes we had a High CPU Utilization on one of our Cisco 4000. When we did a "show processes cpu" and a "show platform health" we can see "CatK4 Mgmt LoPri and K2CpuMan Review" are on a high cpu load.

We think there is a Mac Address problem but we don't find commands to show this. We don't have "mac-address-notification" command and his log command.

Cisco Version :

Cisco IOS Software, Catalyst 4000 L3 Switch Software (cat4000-I9S-M), Version 12

.2(25)EWA, RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Fri 04-Mar-05 16:49 by dchih

Image text-base: 0x10000000, data-base: 0x114D6074

ROM: 12.1(20r)EW1

Dagobah Revision 95, Swamp Revision 3

Do you have some commands to help to resolv problem like that, please ?

Regards,

Richard Rabouin

[Karthick Murugan]

Hi Richard,

can you get the output of "show platform cpu packet statistics"?

Thanks & Regards,
Karthick Murugan
CCIE#39285

[NICOLAS GERVY]

Hi Karthick,

Thanks for your answer. This is the output of the command, actually the problem disappear alone... :

"

#sh platform cpu packet statistics

Packets Dropped In Hardware By CPU Subport (txQueueNotAvail)

CPU Subport  TxQueue 0       TxQueue 1       TxQueue 2       TxQueue 3

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

           0               0               0               0       239898503

           3        48161320               0               0               0

Packets Dropped In Processing Overall

Total                5 sec avg 1 min avg 5 min avg 1 hour avg

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

            33498997         0         0         0          0

Packets Dropped In Processing by CPU event

Event             Total                5 sec avg 1 min avg 5 min avg 1 hour avg

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

Input Acl                     33498933         0         0         0          0

Output Acl                          47         0         0         0          0

SA Miss                             17         0         0         0          0

Packets Dropped In Processing by Priority

Priority          Total                5 sec avg 1 min avg 5 min avg 1 hour avg

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

Normal                          856252         0         0         0          0

Medium                              17         0         0         0          0

High                          32642728         0         0         0          0

Packets Dropped In Processing by Reason

Reason             Total                5 sec avg 1 min avg 5 min avg 1 hour avg

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

UnknownLyr-OutAcl                    47         0         0         0          0

L2DstDrop                            17         0         0         0          0

AclActionDrop                  33498933         0         0         0          0

Total packet queues 16

Packets Received by Packet Queue

Queue                  Total           5 sec avg 1 min avg 5 min avg 1 hour avg

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

Esmp                         892511594        31        20        16          8

Control                      197314769         6         3         0          0

Host Learning                 11829630         0         0         0          0

L3 Fwd Low                     3048714         0         0         0          0

L2 Fwd Low                   262239682        16         5        21        463

L3 Rx Low                    246538680         3         0         1          0

RPF Failure                     630305         0         0         0          0

ACL fwd(snooping)           1283733180        43        30        30         29

ACL log, unreach               4503623         0         0         0          0

Packets Dropped by Packet Queue

Queue                  Total           5 sec avg 1 min avg 5 min avg 1 hour avg

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

Host Learning                     3659         0         0         0          0

L2 Fwd Low                      914516         0         0         0         78

ACL fwd(snooping)                   17         0         0         0          0

"

Regards,

Richard Rabouin

[Karthick Murugan]

HI Nicolas,

When the issue is happening we need to capture the output repeatedly for atleast 3 times to see the CPU queue being choked.

Once you identify the CPU queue which is choked then you can use the following command to find the source of the traffic.

debug platform packet all receive buffer

show platform cpu packet buffered

Thanks & Regards,
Karthick Murugan
CCIE#39285

[NICOLAS GERVY]

Thanks for your answer,

Is this debug add some CPU load, memory load on the device which could crash him ? Is this command returns in output the interface number with high cpu load ?

Regards,

Richard Rabouin

[Karthick Murugan]

Hi Nicolas,

Those commands are meant for CPU troubleshooting and it uses a seperate asic hence it should not intterup the traffic. However, If you are still concerned then you consider doing the same OFF business hours.

Thanks & Regards,
Karthick Murugan
CCIE#39285