Understanding EIGRP Basics
A number of powerful features make EIGRP a real standout from IGRP and other protocols.
The main ones are listed here:
Support for IP and IPv6 (and some other useless routed protocols) via protocol-dependent
modules
Considered classless (same as RIPv2 and OSPF)
Support for VLSM/CIDR
Support for summaries and discontiguous networks
Efficient neighbor discovery
Communication via Reliable Transport Protocol (RTP)
Best path selection via Diffusing Update Algorithm (DUAL)