I know—this chapter has been, you could say, a touch on the extensive side. But it’s really important! EIGRP, the main focus of the chapter, is a hybrid of link-state routing and distance-vector protocols. It allows for unequal-cost load balancing, controlled routing updates, and formal neighbor adjacencies.
EIGRP uses the capabilities of the Reliable Transport Protocol (RTP) to communicate between neighbors and utilizes the Diffusing Update Algorithm (DUAL) to compute the best path to each remote network.
EIGRP also supports large networks through features such as support for VLSM, discontiguous networks, and summarization. The ability to configure EIGRP behavior over NBMA networks also makes it a really hot protocol for large networks. ...