Figure 1 displays the topology that is used in this course to configure EIGRP for IPv4. The types of serial interfaces and their associated bandwidths may not necessarily reflect the more common types of connections found in today’s networks. The bandwidths of the serial links used in this topology were chosen to help explain the calculation of the routing protocol metrics and the process of best path selection.

The routers in the topology have a starting configuration, including addresses on the interfaces. There is currently no static routing or dynamic routing configured on any of the routers.

Figures 2, 3, and 4 display the interface configurations for the three EIGRP routers in the topology. Only routers R1, R2, and R3 are part of the EIGRP routing domain. The ISP router is used as the routing domain’s gateway to the Internet.