ENHANCED IGRP

(EIGRP) AND OPEN

SHORTEST PATH FIRST

(OSPF) By

Anil Kumar Vishwakarma

MCA,MCTS,CCNA

ENHANCED IGRP (EIGRP)

EIGRP Characteristics.

EIGRP Configuration.

Verifying EIGRP.

EIGRP CHARACTERISTICS

Hybrid Protocol.

Cisco-proprietary protocol.

EIGRP works well in large networks.

Default AD (administrative distance) is 90.

EIGRP Metrics use a combination of (B.W, Load, Delay and

Reliability)

Uses an autonomous system number.

Maximum Hop count is 255.

Classless Routing.

Support VLSM and discontiguous networks.

EIGRP CHARACTERISTICS

Support for IP, IPX, and AppleTalk via protocol-

dependent modules

Communication via Reliable Transport Protocol (RTP)

Best path selection via Diffusing Update Algorithm

(DUAL)

Build three table: -

1. Neighbor table: Each router keeps state information about adjacent

neighbors.

2. Topology table: acted upon by (DUAL). Use to determine the best

path for routing packet.

3. Routing table: Store routes.

EIGRP CONFIGURATION

EIGRP CONFIGURATION

Configuring Discontiguous Networks

Lab_A(config)#router eigrp 100 Lab_A(config-router)#no auto-summary Lab_B(config)#router eigrp 100 Lab_B(config-router)#no auto-summary

VERIFYING EIGRP

Description/Function Command

Shows the entire routing

table show ip route

Shows only EIGRP entries in

the routing table show ip route eigrp

Shows all EIGRP neighbors show ip eigrp

neighbors

Shows entries in the EIGRP

topology table show ip eigrp topology

OPEN SHORTEST PATH FIRST

OSPF Characteristics.

OSPF Terminology

OSPF Configuration.

Verifying OSPF.

OSPF and Loopback Interfaces.

Troubleshooting OSPF.

OSPF CHARACTERISTICS

Link State Protocol.

Open Standard protocol.

OSPF works well in large networks.

Default AD (administrative distance) is 110.

EIGRP Metrics use Bandwidth.

Uses an autonomous system number.

No Limit Hop count.

Classless Routing.

Support VLSM and discontiguous networks.

OSPF CHARACTERISTICS

Support IP only.

Best path selection via Dijkstra algorithm.

Manual Summarization.

Build three table: -

1. Neighbor table: Each router keeps state information about

adjacent neighbors.

2. Topology table: acted upon by (Dijkstra). Use to determine the

best path for routing packet.

3. Routing table: Store routes.

OSPF TERMINOLOGY

OSPF TERMINOLOGY

Link is an interface on a router.

The Router ID (RID) is the highest IP

address used to identify the router.

OSPF TERMINOLOGY

Link-State: the status of link between

two routers

OSPF TERMINOLOGY

Link-state database (topological database): A

list of information about all other routers in the

internetwork. It shows the internetwork topolog.

OSPF TERMINOLOGY

Area: A collection of routers that has the same area

identification. Each router within an area has the same

link-state information. A router within an area is called

an internal router.

OSPF TERMINOLOGY

Cost (metric): The value assigned to a link.

Based on the bandwidth of the link.

OSPF TERMINOLOGY

Routing table: sometimes known

as the forwarding database.

OSPF TERMINOLOGY

Adjacencies database: A listing of all the neighbors to

which a router has established a bi-directional

communication.

OSPF TERMINOLOGY

Designated router (DR) and backup

designated router (BDR): A router that is elected

by all other routers on the same LAN to represent all

the routers. Each network has a DR and BDR.

OSPF CONFIGURATION

The two basic elements of OSPF configuration:

1. Enabling OSPF.

2. Configuring OSPF areas.

Router#config t

Router(config)#router ospf 1

Router(config-router)#network 10.0.0.0 0.255.255.255

area 0

VERIFYING OSPF

Description/Function Command

Shows the entire routing table show ip route

Display OSPF information for one

or all OSPF processes running on

the router. show ip ospf

the number of links and the

neighboring router’s ID show ip ospf database

Displays all interface-related

OSPF information.

show ip ospf interface

OSPF AND LOOPBACK INTERFACES

Configuring loopback interfaces when using the OSPF routing protocol is

important, and Cisco suggests using them whenever you configure

OSPF on a router.

Loopback interfaces are logical interfaces, which are virtual, software-

only interfaces; they are not real router interfaces.

Configuring Loopback Interfaces

Router (config)#int loopback 0

Router (config-if)#ip address 172.16.10.1

255.255.255.255

Router(config-if)#no shut

TROUBLESHOOTING OSPF

What is the error in this configuration if you want to route only ip packet begin with 10 then any number ?

Router(config)#router ospf 1

Router(config-router)#network 10.0.0.0 255.0.0.0 area 0

RouterB#sh ip ospf interface e0/0

Ethernet0/0 is up, line protocol is up

Internet Address 172.16.1.1/16, Area 0

Process ID 2, Router ID 172.126.1.1,

Network Type BROADCAST, Cost: 10

Transmit Delay is 1 sec, State DR, Priority

1

Designated Router (ID) 172.16.1.1,

interface address 172.16.1.2

No backup designated router on this

network

Timer intervals configured, Hello 10, Dead

40, Wait 40, Retransmit 5

RouterA#sh ip ospf interface e0/0

Ethernet0/0 is up, line protocol is up

Internet Address 172.16.1.2/16, Area 0

Process ID 2, Router ID 172.126.1.1,

Network Type BROADCAST, Cost: 10

Transmit Delay is 1 sec, State DR, Priority

1

Designated Router (ID) 172.16.1.2,

interface address 172.16.1.1

No backup designated router on this

network

Timer intervals configured, Hello 5, Dead

20, Wait 20, Retransmit 5

Thank You