The Windows Server 2003 family will provide two types of clustering services:

“Cluster Service (MSCS). Available only in Windows Server 2003, Enterprise Edition and Datacenter Edition, this service provides high availability and scalability for mission-critical applications such as databases, messaging systems, and file and print services. Multiple servers (nodes) in a cluster remain in constant communication. If one of the nodes in a cluster becomes unavailable as a result of failure or maintenance, another node immediately begins providing service, a process known as failover. Users who are accessing the service continue to access the service, and are unaware that it is now being provided from a different server (node).
Both Windows Server 2003, Enterprise Edition and Datacenter Edition will support server cluster configurations of up to 8 nodes. This change was made to allow increased flexibility for deployments: particularly for geographically dispersed cluster configurations, and to support N+I configurations (N active with I spare). N+I will be particularly important for supporting larger Microsoft Exchange Server deployments using Windows Server 2003 into the future.

Network Load Balancing (NLB). Available in all editions of the Windows Server 2003 family, this service load balances incoming Internet Protocol (IP) traffic across clusters. Network Load Balancing enhances both the availability and scalability of Internet server-based programs such as Web servers, streaming media servers, and Terminal Services. By acting as the load balancing infrastructure and providing control information to management applications built on top of Windows Management Instrumentation (WMI), Network Load Balancing can seamlessly integrate into existing Web server farm infrastructures.”

http://www.microsoft.com/windowsserver2003/evaluation/overview/technologies/clustering.mspx

II. Citrix-Server based consulting

Access to information resources has become a critical issue for organizations from two perspectives – on the one hand, ubiquitous access is essential for growth and competitive advantage; on the other, the struggle to deliver this access in a world of system and user complexity threatens to overwhelm IT. Organizations are looking for a new approach that will not only give users access at their fingertips to the information required to build the business, but also will make IT’s job easier. By replacing a patchwork of tactics with a comprehensive access strategy, delivered with an access infrastructure solution, any organization can become an on-demand enterprise where information is securely, easily and instantly accessible from anywhere, using any device or connection.