ARP updates end communications

Answered Question
Nov 10th, 2008

I have a 7604 that when it updates its Arp tables every 4 hours, communications will go down for 7 min 51 seconds, and when I look at the ARP table at that time the tables are empty. Once the time 7:51 passes then communication are re-established and the ARP tables are fully populated again. I am using s3223_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(18)SXF15. Do you guys have any thoughts?

I have this problem too.
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Correct Answer by owillins about 8 years 3 weeks ago

The issue with CAM table/ARP table timer mismatch causing traffic flooding is related to asynchronous routing environments.

The default timeout period for a CAM entry is 300 seconds, which is 5 minutes. For ARP entries in a router, the default is 4 hours. The only reason I can think of that a router would purge all the ARP entry for a single interface is if the interface itself were to reset.

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Correct Answer
owillins Fri, 11/14/2008 - 14:41

The issue with CAM table/ARP table timer mismatch causing traffic flooding is related to asynchronous routing environments.

The default timeout period for a CAM entry is 300 seconds, which is 5 minutes. For ARP entries in a router, the default is 4 hours. The only reason I can think of that a router would purge all the ARP entry for a single interface is if the interface itself were to reset.

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