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 100Lab_A(config-router)#no auto-summaryLab_B(config)#router eigrp 100Lab_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 neighborsshow 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 tRouter(config)#router ospf 1Router(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 1Router(config-router)#network 10.0.0.0 255.0.0.0 area 0

RouterB#sh ip ospf interface e0/0Ethernet0/0 is up, line protocol is upInternet Address 172.16.1.1/16, Area 0Process ID 2, Router ID 172.126.1.1, Network Type BROADCAST, Cost: 10Transmit Delay is 1 sec, State DR, Priority 1Designated Router (ID) 172.16.1.1, interface address 172.16.1.2No backup designated router on this networkTimer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

RouterA#sh ip ospf interface e0/0Ethernet0/0 is up, line protocol is upInternet Address 172.16.1.2/16, Area 0Process ID 2, Router ID 172.126.1.1, Network Type BROADCAST, Cost: 10Transmit Delay is 1 sec, State DR, Priority 1Designated Router (ID) 172.16.1.2, interface address 172.16.1.1No backup designated router on this networkTimer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5

Thank You