Load balancing is a concept that distributes the workload across multiple servers or other resources to optimize performance, availability, and scalability. Load balancing can be implemented at different layers of the network, such as the application layer, the transport layer, or the network layer. Load balancing can use various algorithms or methods to determine how to distribute the traffic, such as round robin, least connections, or weighted distribution.
References: CompTIA Server+ Study Guide, Chapter 6: Networking, page 241.