EIGRP (Enhanced Interior Gateway Routing Protocol)

Okay.. we already learn about Distance vector routing protocol (RIPv1&2).
and now we will start with EIGRP.
EIGRP is an Enhanced from IGRP and this protocol was cisco proprietary.
Ok let’s start to learn EIGRP. But wait.. why we start from EIGRP, not the IGRP.
Nowadays people already leave IGRP. They are already migrate to EIGRP. That why we skip to learn about IGRP.
But don’t worry, I will tell a little about IGRP before we learn more about EIGRP.

So let say, what is the difference between IGRP and EIGRP?
good question, First IGRP and EIGRP use different Algorithm.
IGRP using Bellman-Ford, otherwise EIGRP using DUAL algorithm.
Second, IGRP are clasfull routing protocol, EIGRP are classless routing protocol.
IGRP using Periodic Update every 90 second, otherwise EIGRP using Bounded Update.

Sometimes EIGRP is also being called “Hybrid Routing Protocol) because this protocol have a surplus in Distance Vector Routing Protocol (DVRP) and Link State Routing Protocol (LSRP), although EIGRP is being catagorized to DVRP.

Characteristic of EIGRP:
=> Using RTP (Reliable Transport Protocol) in Layer 4
=> EIGRP using 3 Update type to update the Routing table information (Bounded, Triggered, Partial).
=> EIGRP using DUAL (Diffusing Update Algorithm) to count metric. The main function of DUAL is to prevent routing loop.
=> EIGRP had 3 table :Routing table, Topology table, and Neighbor Table.
=> EIGRP had authentication Feature.
=> Automatic Summarization
=> sending with multicast (224.0.0.10)
=> AD EIGRP (Internal EIGRP =90, External EIGRP =170, Summary EIGRP =5)

The Advantages EIGRP than the other routing protocol.
- Fitur PDM (Protocol Dependant Module) which support multiple network protocol (IP,IPX,Appletalk)
- It is also support unequal load balancing
- save backup path
- Combining the Advantages from DVRP (easy to config and not using much processor) and LSRP ( fast convergence & support Complex topology)

EIGRP had 3 table
- Routing Table
- Neighbor table : Information directly connected network that join EIGRP.
- Topology table : Information for all router that join EIGRP

5 EIGRP Packet Type:
1. Hello Packet => to establish connection with directly connected network and maintain those connection.
2. Update Packet => to sending update to another router that join EIGRP
3. Query Packet => to ask another router about the location network if there are some network down.
4. Reply Packet => to answer query packet
5. Acknowledge Packet => to ack all EIGRP packet except Hello packet.

To understand more about EIGRP, let us start below exercise.
Below is the network topology:

I will not explain how to set the IP address and etc. I assume you already understand. If you don’t understand how to set IP, you can see back in my previous post.

After set all IP address, first we go to Router 0.
##: noted

Router>en
Router#conf t
Router(config)#router eigrp 10
##10 is a number for the Autonomous System (AS)
Router(config-router)#network 192.168.1.0
Router(config-router)#network 192.168.0.0
##Add directly Connected Network
Router(config-router)#exit
Router(config)#exit

Go to Router 1

Router>en
Router#conf t
Router(config)#router eigrp 10
Router(config-router)#network 172.10.0.0
Router(config-router)#network 192.168.0.0
Router(config-router)#exit
Router(config)#exit

After that u can try to PING each other PC in those network to make sure the network is already connected each other.