flapping between ports

Manu Singh · ‎12-15-2008

Hi all,

I recieved the following error message please give ur suggession to resolve the incident.'

044003: Dec 16 00:41:19: %SW_MATM-4-MACFLAP_NOTIF: Host 0021.5aec.e7a6 in vlan 170 is flapping between port Fa2/0/9 and port Fa2/0/10

044004: Dec 16 00:41:29: %SW_MATM-4-MACFLAP_NOTIF: Host 0021.5aec.e7b6 in vlan 170 is flapping between port Fa2/0/8 and port Fa2/0/7

044005: Dec 16 00:41:30: %SW_MATM-4-MACFLAP_NOTIF: Host 0021.5aec.e7a6 in vlan 170 is flapping between port Fa2/0/9 and port Fa2/0/10

044006: Dec 16 00:41:42: %SW_MATM-4-MACFLAP_NOTIF: Host 0021.5aec.e7a6 in vlan 170 is flapping between port Fa2/0/9 and port Fa2/0/10

glen.grant · ‎12-15-2008

Looks like a loop of some type or you have access points hung off those ports and the user is roaming between AP's.

williamsdo · ‎12-15-2008

I would start by removing the cat5 cable from port FA2/0/7 and work my way up to FA2/0/10 and see if the errors stops and which port being disconnected cause the error to stop. Also the same mac address is on all of the ports investigate who or what has the mac address 0021.5aec.e7a6, and try and figure if they are moving from port to port. That all I can say from the info provided. HTH

ROBERT ISAACS · ‎12-16-2008

Do you have a server with teaming NIC's that might be shouting the same MAC address? I've had that happen before.

crow930us · ‎12-16-2008

The problem of MAC FLAP might be resolve by the following method:.

Check with the server providers to see if the OS and server platform support 'NIC' Teaming (NIC Bonding).

NIC teaming allows users to group two or more physical NICs into a single logical network device called a bond. Once a logical NIC is configured, the virtual machine is not aware of the underlying physical NICs. Packets sent to the logical NIC are dispatched to one of the physical NICs in the bond and packets arriving at any of the physical NICs are automatically directed to the appropriate logical NIC.

If one of the underlying physical NICs is broken or its cable has been unplugged, server will detect the fault condition and automatically move traffic to another NIC in the bond. This capability eliminates a single point of failure for any one physical NIC and makes the overall network connection fault-tolerant.