EAPS Inconsistent IPARP vs. FDB entry. MAC address learned on disabled port
The MLAG peers ISC link is part of at least one EAPS ring. One of the MLAG ports is down. When the EAPS ring re-converges from a failure any end-system normally reachable via the remaining MLAG port becomes unreachable.
1. Reported behaviour appears when one of the MLAG ports is down. 2. In such condition, FDB will point to MLAG port in software(show fdb) and it will point to ISC port in Hardware. 3. After the EAPS ring gets completed, an FDB flush is initiated in the ring ports including ISC port. 4. FDB is deleted in hardware but it is present in software still pointing to the MLAG port (Not flushed as it is not part of EAPS). 5. After the next checkpoint message, the switch fails to program the FDB entries in kernel and hardware as it is already present according to software. 6. ARP replies are not processed as a result of this mismatch across the layers.
Upgrade to firmware version 220.127.116.11-patch1-7 or higher.