Multiple network adapters in multicast mode

  • Article

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Multiple network adapters in multicast mode

This model is suitable for a cluster in which ordinary network communication among cluster hosts is necessary and in which there is heavy dedicated traffic from outside the cluster subnet to specific cluster hosts.

Advantages

  • Because there are at least two network adapters, overall network performance is typically enhanced.

  • Ordinary network communication among cluster hosts is permitted.

Disadvantages

  • This model requires a second network adapter.

  • Some routers might not support the use of a multicast media access control (MAC)address. This only affects the Network Load Balancing/MAC address (not all MAC addresses) and only when dynamic ARP replies are sent by the cluster to the router. not all MAC addresses.

For more information, see Multiple network adapters and Using a router in Network Load Balancing system requirements.

Important

  • Network Load Balancing does not support a mixed unicast/multicast environment within a single cluster. Within each cluster, all network adapters in that cluster must be either multicast or unicast; otherwise, the cluster will not function properly.

    There is no restriction on the number of network adapters that can be bound to network load balancing on each computer: Different hosts can have a different number of adapters, but you can never have more than one adapter on a computer be part of the same cluster.

    Different adapters on each computer can be part of different clusters, and they can all reside on the same subnet. You can also host multiple clusters on the same network adapter. For more information, see Understanding virtual clusters.

  • Before you install Network Load Balancing, it is vital that you review Checklist: Enabling and configuring Network Load Balancing, including the sections on cluster parameters, host parameters, and port rules. It is highly recommended that you read through these sections before configuring Network Load Balancing.