February 10, 2016 by James

Troubleshooting High CPU usage on a Catalyst 6500 due to ARP Input.

Faced with a Cat 6500 with dual Sup 2T's that responded to a  show running-config with Unable to read Configuration.Try Again later and general cli slowness, it became aparrent that the CPU load on the supervisors was massive: cat-6500-sw1#sh proc cpu sorted CPU utilization for five seconds: 99%/83%; one minute: 99%; five minutes: 99% PID…

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February 8, 2016 by James


ARP – RFC 826 Proxy ARP – RFC 1027 ARP request is sent with required IP as the Target, and the Target MAC address field set to all-zeros.