EIGRP Week: Tuesday

Hello to EIGRP Tuesday where we will get a 5 router topology up and humming on EIGRP.

5 router funhouse

The above topology shows 5 routers, R1 - R5 - our goal will be to get EIGRP running on all devices.

If you want to try this at home you can download the GNS3 project files ->here<-

To get EIGRP to form neighbor relationships the following parameters must be given:

1. All routers must be in the same AS (Autonomous System)
2. If authentication is used:  key number, the password, and the date/time the password expires must match
3. Neighbors need to be on the same subnet.

Router R1 is about to be configured

We will now start with router R1 enable the EIGRP process. First we do a "show ip interface brief" to get an overview of the interfaces we want to get involved with the EIGRP process:

Interface                           IP-Address      OK?  Method Status                Protocol
FastEthernet0/0            192.168.1.1     YES   NVRAM  up                    up     
FastEthernet0/1            192.168.2.1     YES   NVRAM  up                    up     
Ethernet1/0                   192.168.3.1     YES   NVRAM  up                    up     
Loopback0                    192.168.0.1     YES   NVRAM  up                    up     

Since every subnet is in the 192.168.X.X and we want to enbale everything for the EIGRP process today we have several options to do so:

Example 1
!
router eigrp 1
 network 192.168.0.0
!

Example 2
!
router eigrp 1
 network 192.168.0.0 0.0.0.255
 network 192.168.1.0 0.0.0.255
 network 192.168.2.0 0.0.0.255
 network 192.168.3.0 0.0.0.255
!

Example 3
!
router eigrp 1
 network 192.168.0.0 0.0.0.0
 network 192.168.1.0 0.0.0.0
 network 192.168.2.0 0.0.0.0
 network 192.168.3.0 0.0.0.0
!


Example 4
!
router eigrp 1
network 0.0.0.0 0.0.0.0

!

Note that way number 4 is the quick and dirty way which will involve EVERY interface that is and will ever be on the router to EIGRP AS 1. For our little lab enviroment this is just the perfect way, but be carefull tossing this out in a production network where a little more specific interface selection might be requiered. 

But for now - one statement to rule them all - copy and paste the following on every router:

conf t

router eigrp 1
network 0.0.0.0 0.0.0.0

no auto-summary

exit

EIGRP will start to send out HELLO messages out of all infaces and form neighbor relationships.

Hello neighbor how is you doing?

To verify that our little network is routing from end to end lets go to R5 and ping the Loopback address of R1.

5 out of 5 - what a PING !!!!!

If you like you can ping all the other interfaces of a every router to verify connectivity but let`s assume that every is up and running like it should. Tomorrow we will take a look into how EIGRP is selecting the routinpaths across the network and see how we can play around with it.