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New Member

CPU Utilization caused by port negotiation


We have a problem on newly installed 3750's whereby we also have recently had new Dell PC's causing the CPU processes to reach 100% when they are rebooted. The high CPU % is only noticed when the NIC's are restarted.WOL has been disabled and the newest drivers and BIOS ver have been installed on these NICs. Autonegotiation has been configured on the NIC's since these switch ports will be used for IPT in the near future.

IOS 12.2(40)SE on 3750's and DELL model is 755 with Intel NIC's. Has anyone come across similar problems?

Sample port config:

interface FastEthernet1/0/6

switchport trunk encapsulation dot1q

switchport trunk native vlan 859

switchport mode trunk

switchport voice vlan 860

srr-queue bandwidth share 10 10 60 20

priority-queue out

mls qos trust cos

auto qos voip trust

no mdix auto

spanning-tree portfast trunk



Re: CPU Utilization caused by port negotiation

Here is the URL which will help you how does the high cpu utilization occurs and troubleshooting for that :

New Member

Re: CPU Utilization caused by port negotiation


Thanks for the link. Its a useful read.

We managed to upgrade the IOS to 12.2(44)SE1 and the results have been very promising. It seems Cisco has deferred several previous IOS versions due to bug fixes. We are waiting to continue testing as well co-ordinating with live enviroments. Will keep updating.