EIGRP named mode

Since IOS 15, EIGRP has a new method of configuration called named mode EIGRP.  With the “classic” version of EIGRP that we used before IOS 15, we configured EIGRP globally and some other things (like authentication) on the interfaces. With named mode EIGRP, we do everything globally.

If you try to configure EIGRP on an IOS 15.x router you will see this:

R1(config)#router eigrp ? <1-65535> Autonomous System WORD EIGRP Virtual-Instance Name

Instead of an AS number, we can also choose a name. This essentially allows EIGRP named mode to have multiple address families and autonomous system number combinations, providing a more hierarchical and overall better approach to EIGRP configuration.