For high-traffic, high-availability websites and applications, Numaria uses load balancing multi-port switches. These switches do load balancing in hardware and can handle extremely heavy loads. They also have advanced features, including: Intrinsic Persistence Checking, Comprehensive Server Checking and Stateful Fail-over.

Load balancing was developed to address the problem of overloaded servers. A Server Load Balancer is placed between the client and a group of servers and configured so that, although multiple servers may be on one side of the SLB, they appear to be one very large and powerful server that never goes down. The SLB takes on the IP address that the client is trying to contact, becoming a Virtual Server that directs the client to one of the servers in the load balanced group of servers. The SLB may be a dedicated device that uses software to perform all traffic management decisions or it may be a multi-port switching device that uses hardware to perform these functions allowing for greater performance.

For more information on SLB, read this White Paper.