Load balancing is a technique used by data centers to distribute the workload equally between multiple servers in order to achieve the optimum performance, efficiency, capacity and reliability. Load balancing is made possible by load balancers which are physical or virtual appliances which are placed between the client and the backend servers. These devices are programmed to detect the incoming workload and the current idle capacity of every server and based on this information they route the load towards the server which is having less workload at that moment. Load balancing allows data centers to keep running smoothly even when there is excessive or uneven workload. Another benefit of deploying the load balancing technique is that it has a provision of failovers. Failovers are the backup servers to which the load balancers transfer the workload should there be any technical fault with any of the primary servers.
In a casual sense, call centers tend to use the term load balancing to refer to the technique of routing incoming calls (workload) to the call center agents based on their capacity and capability. One can also consider an IVR system to be a load balancer in such scenarios as for every incoming call it checks which call center agent is available and transfers the call to that particular agent after skipping the busy ones.