Network Load Balancing May Stop in Unicast Mode with Some FDDI Network Adapters

This article describes why Network Load Balancing (NLB) in unicast mode may not work with all Fiber Distributed Data Interface (FDDI) network adapters.

Network Load Balancing in unicast mode may not work with all FDDI network adapters. NLB's unicast mode changes the media access control (MAC) address of every host to the same MAC address. Some FDDI adapters override NLB's management of MAC addresses. The result is that 'heartbeat' packets are dropped, and the cluster fails to converge.