Set of Network Load Balancing Clusters Running IIS 6.0
Updated: September 1, 2003
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
Diagram 2 depicts the Network Load Balancing clusters of Web servers that support the Microsoft.com Web site. This set of clusters consists of six Network Load Balancing clusters. Each cluster has 10 servers running IIS 6.0.
Each of the six clusters has a unique virtual IP address (VIP). However, all six of these clusters are addressable by the URL www.microsoft.com. Internet traffic is initially routed to one of the six VIPs by round robin. Round robin is a simple mechanism used by DNS servers to share and distribute loads for network resources. Here, round robin is used to rotate the order of VIPs that are used in response to a query from the Internet to www.microsoft.com.
Each host within each of the six clusters has two network adapters: the cluster adapter, which connects to the Internet and is bound to one of the VIPs, and the management adapter, which connects to the Microsoft corporate network by a perimeter network. All 10 of the hosts in each individual cluster have the same VIP that is bound to the hosts cluster adapter (shown by the red line). In contrast, the blue line represents the set of 10 unique IP addresses (one for each host in the cluster) that are bound to its management adapter. For more information about the two network adapters, see Diagram 3.
For more information about the design considerations and configuration details of these Network Load Balancing Clusters, see Reasons for Using Network Load Balancing, earlier in this document, and Configuration of the Network Load Balancing Clusters at Microsoft.com later in this document.