What is Load balancing ?

Load balancing

Aggregated multiple components in order to achieve a total processing capacity above individual capacity, in a scalable way.
It allows more operations being performed simultaneously by the time it takes a component to perform only one.
 
Using LB a single operation :

• will still be performed on a single component at a time
• will not get faster than without load balancing.

It always requires at least as many operations as available components to make use of all components and to fully benefit from the load balancing.
 
Real world example 
Number of lanes on a highway which allows as many cars to pass during the same time frame without increasing their individual speed.
Examples of load balancing

• Process scheduling in multi-processor systems
• Link LB (eg: EtherChannel, Bonding)
• IP address LB (eg: ECMP, DNS roundrobin)
• Server LB (via Load balancers)

Load balancer
The mechanism or component which performs the load balancing operation.