Load balancing is a common method of taking information destined to a single device and distributing it to multiple devices. Load balancing techniques and algorithms were described in Chapter 21.
Load balancing is usually implemented in large clustered environments, where servers are grouped based on their function. It facilitates server maintenance, downtime, and load sharing in such environments. If you don’t have a busy server there is no need to use load balancing, but as more users need access to that service, you might consider using server clusters with load balancing instead.
Load balancing is usually implemented with the Common Address Redundancy Protocol (CARP), which allows you to assign the same IP address to multiple hosts. CARP is an open standard protocol and is similar in functionality to HSRP or VRRP First Hop Redundancy Protocols. CARP offers transparency to the user because if a server fails, the service is still available via other servers with the same IP address.