EIGRP(Enhanced Interior Gateway Routing Protocol) is Cisco propriety protocol, but recently they have made Eigrp an Open Standard Protocol by releasing its draft so that other companies can also use it. Eigrp protocol is like a Igrp but with little bit more enhancement here and there. Since we already learned what is Dynamic routing, today we will focus on Eigrp only and its characteristics in detail, so lets get into it.
READ ALSO:- WHAT IS DYNAMIC ROUTING?
READ ALSO:- WHAT IS STATIC ROUTING?
EIGRP protocol Overview
Enhanced Interior Gateway Protocol is a dynamic hybrid/advanced distance vector protocol that uses both properties of link state as well as distance vector protocol. Eigrp uses composite metrics to find the best path to reach the destination network.
The metric value used by Eigrp is defined as K values which ranges from 1 to 5. Down below is the meaning of each K values.
- K1 = Bandwidth.
- K2 = Load.
- K3 = Delay.
- K4= Reliability.
- K5= Mtu(Maximum Transmission Unit).
But by default Eigrp uses composite metrics of K1 and K3 ie bandwidth and delay. You can change the default composite metrics in Eigrp configuration mode.
By default it has hop count of 100 but it can be extended up to maximum 255, also don't let this confuse you, Eigrp doesn't use hop count as metric like RIP(Routing Information Protocol) does. Here hop count refers to how many routers Eigrp can send route update packet to before it will be discarded.
Eigrp Protocol uses ASN(Autonomous System Numbering) to identify the group of routers running same routing protocol strategy and is under common administration.
It uses Packets like Hello Pkt, Ack Pkt, Update Pkt, Query and Reply to record, maintain and update info from neighbor router into routing table and neighbor table.
READ ALSO:- WHAT IS DYNAMIC ROUTING?
READ ALSO:- WHAT IS STATIC ROUTING?
EIGRP protocol timers:-
Eigrp uses two types of timer to maintain adjacency neighbor relationship.
- Hello Timer- After every 5 seconds hello packet is send from each port of the router to discover neighbor.
- Hold Timer:- This timer determines how many seconds a router will wait to get the hello packet from a neighbor. After 15 seconds it will declare the neighbor dead and it will be removed from the neighbor table and all the route depended upon it will be recalculated.
EIGRP(Enhanced Interior Gateway Routing Protocol) :
Characteristics And Features
Eigrp protocol has the following standout characteristics and features:-
- It supports both Ipv4 and Ipv6.
- Supports both classfull as well as classless networks.
- It includes subnet information in the routing table.
- Supports both VLSM and CIDR networks.
- Supports both contiguous and dis-contiguous networks .
- Eigrp supports both Auto-Summarization and Manual Summarization.
- It Uses DUAL(Diffusing Update Algorithm) for best path selection strategy.
- Its uses RTP(Reliable Transport Protocol) to send route updates.
- In Eigrp the update is change triggered not periodic as in RIP. Change triggered means the update will not be send to the neighbor unless and until there is a change in network topology.
- It uses Multicast (224.0.0.9) and no broadcast for sending update.
- The Administrative distance of Internal Eigrp is 90, whereas for External Eigrp AD is 170
NOTE:- I mentioned Internal and External Eigrp just now. These two are Eigrp types which I will discuss later in my next article.
READ ALSO:- WHAT IS DYNAMIC ROUTING?
0 on: "EIGRP (Enhanced Interior Gateway Routing Protocol)-Characteristics"