Description

Packet loss or duplicate packets of PING/ICMP echo replies may be observed sometimes in the network.

One possibility that may case this issue is MAC move/flap.

Symptoms

PING packet loss or duplicate ICMP echo replies are observed.

Upon further check, we will see MAC move or flap of destination client between downstream and upstream switch ports.

Output of CLI command "show ethernet-switching mac-learning-log | match <MAC Address of dst client>" will show us details. 

xSTP status looks good though. No "TOPO_change" logs are observed either.

Solution

One possibility that may cause this issue is high CPU usage on one of the transit switches, which hangs L2 processes.

Solution is to reduce CPU usage and issue is fixed.

Modification History

2024-04-08 : Article Created