High CPU on Cisco 4507

[Ahmet Erkol]

Hi,

We have Cisco 4507R-E and we see a high CPU even at nights when there is no much more traffic on the switch.

Here are the some cpu cpmmand outputs.

sh proc cpu sort

  69    52873350   108228799        488 13.35% 10.93% 10.60%   0 Cat4k Mgmt LoPri

  68    62281851   265686819        234  7.19%  6.88%  7.03%   0 Cat4k Mgmt HiPri

sh platform health

K5L3Unicast Adj Tabl   2.00  14.56     15      7  100  500   15  15    8  607:36

sh platform cpu packet stat

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

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

Sa Miss                        1618486         8         1         0          0

Input Acl Fwd                        1         0         0         0          0

Packets Dropped In Processing by Priority

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

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

Medium                         1618486         8         1         0          0

High                                 1         0         0         0          0

Packets Dropped In Processing by Reason

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

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

STPDrop                            3044         0         0         0          0

Tx Mode Drop                    1615443         8         1         0          0

Total packet queues 64

Packets Received by Packet Queue

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

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

Esmp                         169650262        97        92        94         87

Input ACL fwd(snooping)            3438         0         0         0          0

Host Learning                  1618477         9         1         0          0

L2 Control                     8684569         5         3         2          0

Ttl Expired                      12559         0         0         0          0

Adj SameIf Fail                     23         0         0         0          0

Bfd                               1614         0         0         0          0

L2 router to CPU, 7           29932895        12         7        10         11

L3 Glean, 7                   65336474        20        20        25         23

L3 Receive, 7                  3202292         2         3         1          0

Packets Dropped by Packet Queue

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

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

L3 Glean, 7                      84216         0         0         0          0

I cannot find anything about the process K5L3Unicast Adj Tabl on yhe internet.

[Jon Marshall]

Ahmet

I cannot find anything about the process K5L3Unicast Adj Tabl on yhe internet.

From the Troubleshooting High CPU on the 4500-E doc -

K5L3 process name

Different Layer 3 process that managing various Layer 3 function and tables such as forwarding entries, adjacencies, multicast RET entries, and statistics

full link -  http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/troubleshooting/cpu_util.html

You should also look at the more general Troubleshooting High CPU on the 4500 as it applies to your switch as well -

http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a00804cef15.shtml

Jon

[Ahmet Erkol]

Anything else. I didnt find anything really.

Sent from Cisco Technical Support iPhone App

[Jose Solano]

Hi

The platform-process “K5L3Unicast Adj Tabl”, that causes the high CPU usage is a  platform-process that is active when a new MAC address has been learned and the adjacency table is rewritten. This takes place when in the switch receives an unknown source MAC address, it’s forwarded to the CPU for MAC address learning.

It could be possible to have a device connected to a switch port sending lots of MAC address randomly and massively forcing the switch to spend all CPU capacity just to process the new MAC addresses.

So next step is check the interface statistics looking for the highest traffic rate. Use this link below in order to troubleshoot this issue and find the top offender interface.

http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a00804cef15.shtml#trouble

Hope this helps.