Network Load Balancing system requirements

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

Network Load Balancing system requirements

Network Load Balancing is designed to work as a standard networking device driver in the Microsoft® Windows Server 2003 family of products. Because Network Load Balancing provides clustering support for TCP/IP-based server applications, TCP/IP must be installed in order to take advantage of Network Load Balancing functionality. The current version of Network Load Balancing is designed for use with Ethernet network adapters. It is not compatible with asynchronous transfer mode (ATM), ATM local area network (LAN) emulation, or token ring. It has been tested on 10 megabits per second (Mbps), 100 Mbps, and gigabit Ethernet networks with a wide variety of network adapters, including teaming network adapters listed as compatible with the Windows Server 2003 family of products. For information regarding compatible hardware, click the appropriate link in Support resources.

On x86-based computers, Network Load Balancing uses between 750 kilobytes (KB) and 27 MB of RAM per network adapter during operation, using the default parameters and depending on the network load. The parameters can be modified to allow up to 84 MB memory to be used. Typical memory usage ranges between 750 KB and 2 MB.

On x64-based computers, Network Load Balancing uses between 825 KB and 32.3 MB of RAM per network adapter during operation, using the default parameters and depending on the network load. The parameters can be modified to allow up to 102 MB memory to be used. Typical memory usage for x64-based computers ranges between 825 KB and 2.5 MB.

For optimum cluster performance, you should install a second network adapter on each Network Load Balancing host. In this configuration, the first network adapter handles the network traffic addressed to the server as part of cluster, while the second network adapter is used for intra-host communication.

It is important to understand that it is possible to use Network Load Balancing with only a single network adapter. For more details, see Single network adapter limitations.

Note

  • Network Load Balancing can operate in two modes: unicast and multicast. Unicast support is enabled by default. To enable multicast support, see Enable multicast support.

Using a router

If Network Load Balancing clients are accessing a cluster through a router when the cluster has been configured to operate in multicast mode, be sure that the router meets the following requirements:

  • Accepts an Address Resolution Protocol (ARP) reply that has one media access control (MAC) address in the payload of the ARP structure, but appears to arrive from a station with another MAC address, as determined by the Ethernet header

  • Accepts an ARP reply for a unicast IP address with a multicast MAC address in the payload of its ARP structure

These conditions allow the router to map the cluster IP addresses to the corresponding MAC address. If your router does not meet these requirements, you can also create a static ARP entry in the router. Cisco routers require a static ARP entry because they do not support the resolution of unicast IP addresses to multicast MAC addresses.