hardware load-balancing device (HLD)

A hardware load-balancing device (HLD), also known as a layer 4-7 router, is a physical unit that directs computers to individual servers in a network, based on factors such as server processor utilization, the number of connections to a server, or the overall server performance. The redirection process is one form of load balancing.

The use of an HLD minimizes the probability that any particular server will be overwhelmed and optimizes the bandwidth available to each computer or terminal. In addition, the use of an HLD can minimize network downtime, facilitate traffic prioritization, provide end-to-end application monitoring, provide user authentication, and help protect against malicious activity such as denial-of-service (DoS) attacks.