EIGRP named mode has been around for years. It is a bit different from the classic EIGRP that most Engineers are used to but it gives you more control and an edge in terms of troubleshooting as all the configuration are centric basically. At this point, if you are unfamiliar with EIGRP, I would suggest to read my post about EIGRP first here.

We will be using the following topology to demonstrate some of the key difference between EIGRP named and classic mode.

All right let’s dive in and start our configuration. At this point, our IP addresses are preconfigured…

EIGRP Classic Mode:

Good ! That’s all there is to it with the classic mode approach. Let’s configure EIGRP named mode at the HeadQuarter…

Here note that once you enter the “?” after “router eigrp, you have 2 options. The first option is your traditional EIGRP mode and the second option allows you to specify a name instance for this EIGRP process. Note that the Name is case sensitive.

It is important to note that EIGRP process does not kick off until you specify the Address-Family and Autonomous System number first

For IPv4:

R2(config-router)#address-family ipv4 unicast autonomous-system “AS-Number”

For IPv4 VRF:

R2(config-router)#address-family ipv4 unicast vrf Customer_A autonomous-system “AS-Number”

For IPv6:

R2(config-router)#address-family ipv6 unicast autonomous-system “AS-Number”

For IPv6 VRF:

R2(config-router)#address-family ipv6 unicast vrf site_A autonomous-system “AS-Number”

With this Named mode, we can create a single Instance of EIGRP, which can be used for all address family type as shown above. You can also use the “shutdown” command under a specific address-family to turn off the entire instance.

So at this point, we should have EIGRP adjacency. Let’s check…

Perfect ! Note that Named EIGRP has 3 configuration modes which are as followed:

1) address-family configuration mode – (config-router-af)#

2) address-family interface configuration mode – (config-router-af-interface)#

3) address-family topology configuration mode – (config-router-af-topology)#

Let me show you the option we have with the address-family configuration mode:

Here we can configure the network prefixes, set the neighbors, adjust the metric and so on…

Let’s see what we have with the address-family interface configuration mode…

Here we also have several options such as authentication, set the hello parameters, set the interface to passive and so on…

Let’s see what we have with the address-family topology configuration mode…

We also have many different configuration options here. We can modify the advertising metric parameters, alter the default AD; Redistribution is also done here.

Let’s now configure a couple of features in both version in order to get a baseline comparison. Let’s start with the classic version of EIGRP…

Noticed how redistribution is done under the EIGRP process in this version but authentication and hellos are done under the interface level ? Let’s configure the same parameters in EIGRP named mode…

Ah ! Noticed the difference here ? The authentication and hello intervals are done under the IPv4 address family under the same EIGRP process rather than at the interface itself. We can also redistribute prefixes under “Topology base”.

Note that for authentication to work here, we have to create a key-chain. That’s another topic, but here is what the configuration looks like on both routers…

Note that the Key Chain name is arbitrary and does not have to be the same as the key-string. For the sake of this topic, I just chose “cisco” but you’d want to use something a bit more complex than that when deployed in a production environment.

We should be good for today… I’ll talk to you guys later.