Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco routing protocol that is designed to address the shortcomings of both distance vector and link-state routing protocols. This chapter expanded on the underlying technologies within EIGRP, including the path selection process, changes in topology, load balancing, authentication, and troubleshooting common problems.
The following summarizes the key points that were discussed in this chapter:
- EIGRP is a classless routing protocol that supports VLSM.
- Path selection is based on several factors.
- EIGRP keeps a next-best alternative path, called a feasible successor, for fast convergence.
- EIGRP supports unequal-cost load balancing.
- EIGRP uses MD5 authentication for router authenticity.
- Troubleshooting EIGRP requires resolving link, neighbor, redistribution, and routing issues.
- The following commands help you troubleshoot EIGRP issues: show ip eigrp neighbor, show ip eigrp topology, show ip eigrp interface, and show ip route.