Cluster Parameters

By default, Network Load Balancing operates in unicast mode to ensure full compatibility with all makes of routers. In some cases, you might want to switch to multicast mode in order to avoid the use of a second network adapter for those communications between cluster hosts that are unrelated to cluster operations (for example, for content replication). If you switch to multicast mode, be sure that your router is compatible with this mode. For more information about the unicast and multicast modes, see Windows 2000 Network Load Balancing Help.

In unicast mode, Network Load Balancing on each host causes the network adapter's media access control address to be replaced with the cluster MAC address. (The media access control address is the hardware address, as distinct from the IP address.)

In multicast mode, the Network Load Balancing driver on each host retains the network adapter's media access control address and adds a multicast media access control address.

Note

Network Load Balancing multicast mode is level-2 multicast. Do not confuse it with IP multicast. The virtual IP address must not be an IP multicast address.

For more information about multicast and unicast modes in Network Load Balancing, see Windows 2000 Network Load Balancing Help.