Enhanced Interior Gateway Routing Protocol (EIGRP)

Enhanced Interior Gateway Routing Protocol, or EIGRP, is a dynamic Interior Gateway Protocol used to calculate and manage routes within a network. Originally developed by Cisco, EIGRP uses the Diffusing Update Algorithm (DUAL) to determine suitable network paths and rapidly provide alternative routes when the network topology changes. By default, its route calculation considers factors including bandwidth and delay. Rather than regularly transmitting complete routing tables, EIGRP exchanges targeted routing information with neighbouring routers when relevant changes occur. This helps reduce additional network traffic. EIGRP also supports Equal-Cost Multipath and Unequal-Cost Load Balancing. The protocol is primarily used in enterprise networks with Cisco networking infrastructure.