vCDNI warning message

Hello,

Does anyone know what these messages from vmkernel.log mean exactly? We have 1000s of them.

2013-03-17T03:45:27.939Z cpu23:8215)vsla-fence: Fence_Decapsulate:297: port:41001cb49420:OPI:{02,000015} Drop unicast packet with hostKeyMac as dest mac
2013-03-17T03:45:27.939Z cpu23:8215)vsla-fence: Fence_Decapsulate:297: port:41001cb55ad0:OPI:{02,000036} Drop unicast packet with hostKeyMac as dest mac
2013-03-17T03:45:27.939Z cpu23:8215)vsla-fence: Fence_Decapsulate:297: port:41001cb56e00:OPI:{02,00001d} Drop unicast packet with hostKeyMac as dest mac
2013-03-17T03:45:27.939Z cpu23:8215)vsla-fence: Fence_Decapsulate:297: port:41001cb43f60:OPI:{02,00001a} Drop unicast packet with hostKeyMac as dest mac
2013-03-17T03:45:27.939Z cpu23:8215)vsla-fence: Fence_Decapsulate:297: port:41001cb596d0:OPI:{02,000004} Drop unicast packet with hostKeyMac as dest mac

Thanks.