In today's world, business hours are 24x7. Since Internet buyers and browsers come from around the globe at all hours, downtime is the one thing you can't afford. You need a reliable solution for maintaining and managing highly available Web services, and a solid resiliency or continuity strategy.
A complete resiliency strategy addresses each layer of the service equation: presentation, application logic and data services (see Figure 1 below). There are specific technologies required for each, but for the presentation layer, the technology focuses on load balancing or redirecting service requests to a server farm. Each of the load balancing solutions examined here is designed to meet those requirements. The first is Microsoft Windows Server 2003's native Network Load Balancing Services. The other two are hardware-based—the WebMux Pro from CAI Networks and F5 Networks' Big IP Local Traffic Manager.
