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animedreamer
Beginner

MAC flapping reported between 2 port channels on Nexus 5596

Hi all, I'm seeing messages like the following reported on a Nexus 5596:

2015 Jan  7 12:40:48.954 Switch-5596A %FWM-6-MAC_MOVE_NOTIFICATION: Host 00ab.cdef.0123 in vlan 104 is flapping between port Po5 and port Po10


Po5 is connected to a storage cluster and is configured as an access port. It is connected to 2 Nexus 5596 switches using vpc.

interface port-channel5
  description Storage Shelf 1
  priority-flow-control mode off
  switchport access vlan 104
  spanning-tree port type edge
  spanning-tree bpduguard enable
  speed 10000
  flowcontrol receive on
  vpc 5


Po10 is the uplink to the core switch:

interface port-channel10
  description uplink
  switchport mode trunk
  switchport trunk native vlan 2702
  switchport trunk allowed vlan 64,94,104,124
  spanning-tree port type network
  speed 10000
  vpc 10


Any ideas on why we would be seeing these log messages?

Thank you.

2 REPLIES 2
InayathUlla Sharieff
Cisco Employee

You need to trace this mac address: - 00ab.cdef.0123 and check if this has dual nic card if yes then check if nic teaming is configured correctly ...then shut down one of the link and see if you are learning the same mac address on two different ports?

 

HTH

devils_advocate
Rising star

MAC Flapping is usually a symptom of a misconfiguration between a switch port and end connected storage or server.