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High CPU with 4510R(HELP ME!!!!)

CPU utilization for five seconds: 33%/1%; one minute: 35%; five minutes: 35%

35 12278232681342443097 914 19.75% 19.82% 19.85% 0 Cat4k Mgmt HiPri

36 579466296 259005695 2237 6.00% 8.79% 8.42% 0 Cat4k Mgmt LoPri

Total packet queues 16

Packets Received by Packet Queue

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

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

Esmp 1689959095 271 247 203 195

K2L2 Address Table R 2.00 2.55 12 6 100 500 0 0 0 554:55

K2PortMan Review 2.00 2.96 15 11 100 500 3 3 2 3407:53

K2PacketBufMonitor-P 1.00 2.61 10 1 100 500 3 2 2 2849:05

New Member

Re: High CPU with 4510R(HELP ME!!!!)

Hi ,

Please check with " show platform health " and check for Cat4k Mgmt LoPri and High Pri


- show platform cpu packet statistics


The Catalyst 4500 learns the MAC addresses of various hosts, if the MAC address is not already in the MAC address table. The switching engine forwards a copy of the packet with the new MAC address to the CPU. If there is an excessive number of new MAC addresses for the switch to learn, high CPU utilization can result.


Please find the explanation of HiPri and Lo pri processes;


Each of the platform-specific processes has a target/expected utilization of the CPU. When that process is within the target, the CPU executes the process in the high-priority context. The show processes cpu command output counts that utilization under Cat4k Mgmt HiPri . If a process exceeds the target/expected utilization, that process runs under the low-priority context. The show processes cpu command output counts that additional utilization under Cat4k Mgmt LoPri . This Cat4k Mgmt LoPri is also used to run background and other low-priority processes, such as consistency check and reading interface counters. This mechanism allows the CPU to run high-priority processes when necessary, and the idle CPU cycles that remain are used for the low-priority processes. To exceed the target CPU utilization by a small amount, or a momentary spike in utilization, is not an indication of a problem that needs investigation.


Also try to use sniffer tool inorder to check the traffic . Is it possible to send " show tech -support " output .


Arjun Sarkar

HP india.

Re: High CPU with 4510R(HELP ME!!!!)

Hi There,

Please use the Link below for troublehooting the issue. This is one of the good link that will guide you all the way through.

If you still cannot find the real cause, you can mirror the CPU queues, to really find out the issue.

HTH, Please rate if it does.

-amit singh

New Member

Re: High CPU with 4510R(HELP ME!!!!)

Hi, I have exactly the same problem with OP, in my case, CPU is consistently running CPU at 60% and above, the link given by Amit is great, but it never goes detail about what ESMP is and how to troubleshoot if ESMP is using most CPU cycles. Can I SPAN ESMP (queue 0) to an ethernet port and use ethereal to decode it? my understanding is the ESMP is for internal management, even ethereal can decode it, how does it help me to remedy this problem?

New Member

Re: High CPU with 4510R(HELP ME!!!!)

Could somebody please help me out? or any pointers?


Re: High CPU with 4510R(HELP ME!!!!)

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