Cisco ARP and MAC Address Aging

If you migrate from a Cisco 6500 to a Cisco Nexus switch, keep in mind that the ARP Default Timeout is very different. On the 6500’s it’s 4 Hours and on the Cisco Nexus it’s 25 Minutes.

Nexus 5K/7K:
ARP Default Timeout 1500 Seconds = 25 Minutes
MAC Address Aging 300 Seconds = 5 Minutes

6500:
ARP Default Timeout 14400 Seconds = 4 Hours
MAC Address Aging 300 Seconds = 5 Minutes

Changing the ARP Timeout & MAC Aging Time on Nexus:

ip arp timeout 14400
mac address-table aging-time 14400
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