Hardware load balancing requires a dedicated switch. Industry-leading vendors for load-balancing switches are Cisco, Nortel Networks, and F5. With hardware load-balancing solutions, a second load balancer is often implemented as a passive standby device to provide redundancy. This avoids the active switch from being a SPOF.
One or more virtual IP addresses and port numbers are configured on the load balancers. Each virtual IP address-port number combination in the load balancer is called a virtual server. Each IP address and port number combination on a server is called a real server. One virtual server could be mapped to one or many real servers. Multiple virtual servers can also be mapped to one or many real servers.