Microsoft NLB debugging and Cisco ACE.

NLB multicast address looks something like this:
 03-bf-c0-a8-03-0e


First 2 digits:
      01=IGMP
      02=Unicast
      03=Multicast
The follows by "bf".
Followed by the ip address in hex:
    c0=192, a8=168, 03=3, 0e=14 and thus the IP of 192.168.3.14.

Some equipments will not put this mac in the cam table, like cisco ACE for example.

Nexus 7k/5k behavior:

vlan configuration 10
  layer-2 multicast lookup mac