EIGRPEnhanced interior gateway routing protocol

Featuring EIGRP………….ClasslessCisco proprietaryAutonomous system 1-65536VLSMHybridhop count = 255Support multiple protocols like IP, IPX, Apple talk, Also IPv6.

EIGRP introEigrp is a class les cisco proprietary protocol. It use concept of Autonomous system to differentiate each part of the network using a specific number from 1-655536.

It also support the VLSM technique to save more IP`s for an internetwork.

It is a hybrid routing protocol due to the features of both the DISTANCE VECTOR+LINK STATE.

Eigrp is not able to send the link state update packets like the OSPF but it can send the distance vector update containing the information about the networks.

But EIGRP have some link state characteristics like it can synchronize the routing tables between the neighbors at startup and also use TRIGGER update

EIGRP introMaximum hop counts by the EIGRP is 255.And it can also route multiple protocols like IP,IPX,APPLE TALK etc.It has also the Metrix like

BandwidthloadDelayReliability MTU.

Also there is no LOOP control method is required for the EIGRP

EIGRP modules..RTP:- Reliable transport protocol

It is use to create the neighbor ship tables in the router and Distributing the LSA{( Link state Advertisement) information about any link to the all connected routers with that interface} .

RTP send a hello packet to all the neighbors and when the neighbors will reply with acknowledgement packet then it will create a NEIGHBOUR TABLE.

for the RTP processes the EIGRP use the Multicast addresses from the D class {224.0.0.9}.

Eigrp maintain the neighbor table of all its neighbors using the RTP and if there is any router which is not sending any update about it then RTP use multicast update for that router for 15 times and if the router will not make any reply then after the 16th update that router is assumed as unreachable and removed from the neighbourship table

EIGRP DUALDUAL:- Diffusing Update Algorithm

it is the Algorithm which enables the EIGRP to use the DISTANCE VECTOR + LINK STATE methods simultaneously.

like 1.VLSM2.Backup route are possible.3.Send route Queries to the

neighbors if the Destination of the received packet is

unknown.4.Dynamic route Recovery

EIGRP terms..Reported distance:-

it is the Distance between the destination network and the next hop IP address.

Feasible distance :- It is the total distance between the destination and

our router.Successor:- It is the Route with least hop count and listed as the

primary route in the routing table

Feasible successor:-It is the backup route which can be used in case when

the primary route is not available or failed

EIGRP tablesEIGRP use three tables to store the all information's1.Neighbourship table2.LSA table3.Routing table

EIGRP tables1.Neighborship table:-

used to store the information about the routers with whom neighbor ship relation is found.

2. LSA/Topology table:-used to store the information about the every

device in every route in the internetwork by the information received from each neighbor table.

3. Routing table:-store the Routes which are currently used to store

the routing decisions.

EIGRP scenario

EIGRP configurationRouter_A(config)#router eigrp 10

Router_A(config_router)# network 10.0.0.4Router_A(config_router)# network 10.0.1.0Router_A(config_router)#exitRouter_A#wr

Router_B(config)# router eigrp 10Router_B(config_router)# network 10.0.0.4Router_B(config_router)# network 10.0.2.0Router_B(config_router)# exitRouter_B#wr

EIGRP verification

#Show Ip route#show ip route eigrp#show ip eigrp neighbour#show ip eigrp topology

EIGRP neighbor

explanation#show ip eigrp neighbor

H Add/interface hold uptime SRTT RTO Q Seq (ms)

0 192.168.10.6 12 0:31:60 26 200 0 7

H= it indicates in which order neighbor is discoveredHold= how long this route will wait for hello packet to arrive from the specific neighbor.Uptime= for how long the neighbor is connected.SRTT= process of multicasting and unicasting.RTO= Retransmission time out= maximum time for which EIGRP waits before retransmitting a packet to neighbor.Q= it indicates that my massage is In the queue. Seq= sequence number of the last update from the neighbor

EIGRP end.

EIGRP