Symptom

IPv6 traffic drops every 4 hours and IPv6 neighbors are moving to the STALE state after 30 seconds even though traffic is being forwarded through the switch. Traffic does recover, but there will be a short period <1s every 4 hours when traffic is dropped.

Conditions

IPv6 traffic is actively forwarded through the switch but the "show ipv6 neighbors" shows traffic streams in STALE state. Every 4 hours ipv6 nd will expire those STALE entries and remove them from the neighbors table.

Workaround

Adding the following command will stop the switch from dropping traffic every 4 hours. It doesn't stop the switch from moving the "show ipv6 neighbors" into a STALE state. ipv6 nd cache expire refresh the default configuration is: ipv6 nd cache expire

Further Problem Description