Network Load Balancing Services (NLBS) is a Microsoft implementation of clustering and load balancing. There are two modes: Multicast and Unicast. This article isfor NLB with multicast mode.
With Multicast mode NLB server expects to receive the packet with destination MAC address as Multicast MAC address. In general, L3 switch needs to configure static-arp and static-mac simultaneously. However in the case of VDX, that doesn't work correctly due to a limitation.