This document provides an overview of the Enhanced Interior Gateway Routing Protocol (EIGRP) and Open Shortest Path First (OSPF) routing protocols. It describes the key characteristics of EIGRP including that it is a hybrid routing protocol that uses metrics like bandwidth and delay to determine the best path. It also explains how to configure and verify EIGRP. For OSPF, the document outlines that it is an open standard link-state protocol, defines common OSPF terminology, and describes how to configure OSPF areas and verify the protocol. Loopback interfaces and troubleshooting OSPF are also briefly covered.

1. ENHANCED IGRP
(EIGRP) AND OPEN
SHORTEST PATH FIRST
(OSPF)
By
Anil Kumar Vishwakarma
MCA,MCTS,CCNA

2. ENHANCED IGRP (EIGRP)
 EIGRP Characteristics.
 EIGRP Configuration.
 Verifying EIGRP.

3. 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.

4. 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.

5. EIGRP CONFIGURATION

6. 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

7. VERIFYING EIGRP
Description/FunctionCommand
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

8. OPEN SHORTEST PATH FIRST
 OSPF Characteristics.
 OSPF Terminology
 OSPF Configuration.
 Verifying OSPF.
 OSPF and Loopback Interfaces.
 Troubleshooting OSPF.

9. 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.

10. 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.

11. OSPF TERMINOLOGY

12. OSPF TERMINOLOGY
Link is an interface on a router.
The Router ID (RID) is the highest IP
address used to identify the router.

13. OSPF TERMINOLOGY
Link-State: the status of link between
two routers

14. OSPF TERMINOLOGY
Link-state database (topological database): A
list of information about all other routers in the
internetwork. It shows the internetwork topolog.

15. 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.

16. OSPF TERMINOLOGY
Cost (metric): The value assigned to a link.
Based on the bandwidth of the link.

17. OSPF TERMINOLOGY
Routing table: sometimes known
as the forwarding database.

18. OSPF TERMINOLOGY
Adjacencies database: A listing of all the neighbors to
which a router has established a bi-directional
communication.

19. 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.

20. 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

21. VERIFYING OSPF
Description/FunctionCommand
Shows the entire routing tableshow 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 IDshow ip ospf database
Displays all interface-related
OSPF information.show ip ospf interface

22. 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

23. 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

24. Thank You