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Cisco Bug: CSCtd82425 - "GLBP vMAC moves (MAC Flaps) observed on access switch"

Last Modified

Feb 01, 2017

Products (1)

  • Cisco Nexus 7000 Series Switches

Known Affected Releases


Description (partial)

MAC flap is observed for virtual MACs on access switch connected to N7ks, when GLBP is configured. 

%SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.4502 in vlan 100 is
flapping between port Te1/0/1 and port Te2/0/1

The Mac  0007.b400.4502 is the VMAC of the GLBP Group 

This issue happens in a topology where an Layer 2 access switch is dual-connected to two N7ks, and GLBP is configured on those ports terminated as Layer3.  Both the links from access switch have to be in forwarding state, for this problem to happen.  Under  this configuration, the access switch may see MAC flaps for GLBP vMACs.
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