unicast flooding when using CSM

[zhichao]

Hi

The customer got one pair of CSM installed on two switches.

Some servers connected to primary switch (primary CSM), and the rest of servers are connected to the 2nd switch/CSM.

On the 2nd switch, sniffer shows a lot of unicast traffics are flooding to all the ports under the same VLAN (and all the trunking ports).

Is this expected behavior?

Thanks

[Gilles Dufour]

are you in bridge mode ?

Do you have HSRP configured ?

There is a well-known bug regarding flooding

CSCei94412: HSRP packets not bridged by CSM causing flooding

This was fixed in 4.2.3

If that does not apply to you, we will need more information - like config, type of packets being flooded [anything in common to those packets ?]

Regards,

Gilles.

Thanks for rating this answer.

[zhichao]

thanks

However we are not using bridge mode.

If this is not expected behavior, I think i have to go onsite to find out more info and do some troubleshooting....

Regards

[zhichao]

Found the problem.

When the two CSM doing replication, they sent out a lot of unicast traffics flooding the replicacation VLAN.

This does not affect user VLANs.