Planning your networking hardware

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

Planning your networking hardware

Implementing the correct networking infrastructure is integral to trouble-free operation of your server cluster. This section offers the following guidelines for planning your networking hardware:


  • Your network hardware must be selected from the Windows Catalog. For information about hardware compatibility and the Windows Catalog, see Support resources.

  • The nodes of a cluster must be connected by two or more local area networks (LANs); at least two networks are required to prevent a single point of failure. A server cluster whose nodes are connected by only one network is not a supported configuration. The adapters, cables, hubs, and switches for each network must fail independently. This usually implies that the components of any two networks must be physically independent.

  • At least two networks must be configured to handle All communications (mixed network) or Internal cluster communications only (private network). For more information, see Change how the cluster uses a network.

  • Each network connecting the nodes of a cluster must be configured as a single IP subnet. The IP subnet numbers for the networks connecting the cluster nodes must be different. If a cluster node has multiple adapters attached to the same cluster network, only one adapter will be used by the Cluster service; the others will be ignored. Multiple adapters connected on one node to the same network will not provide fault tolerance or load balancing and is not recommended.

  • Teaming network adapters on all cluster networks concurrently is not supported. At least one of the cluster networks that is enabled for internal communication between cluster nodes (typically a private network) must not be teamed. The use of teaming network adapters on other cluster networks is acceptable; however, if communication problems occur on a teamed network, Microsoft Product Support Services will require that teaming be disabled. If this action resolves the problem or issue, then you must seek further assistance from the manufacturer of the teaming solution.

  • Use a virtual LAN (VLAN) to connect the nodes of a cluster as long as all of the nodes view it as the same IP subnet. The one-way communication latency between any pair of cluster nodes on the VLAN must be less than 0.5 second. The VLAN must fail independently of all other LANs or VLANs used to connect the nodes of a cluster. Again, this usually implies that the VLAN must be constructed of components that are physically independent from other networks used in the cluster. Both the hardware and software configuration of a VLAN must be certified and listed on the Windows Catalog.


  • Make sure that the network adapters used in all cluster nodes are identical, that is, each is the same make, model, and firmware version.

  • Reserve one network exclusively for internal communications between nodes; that network must not be teamed.