OSPF (Open Shortest Path First) Single Area Configuration and Testing By Nur Wajianto Collinsvile, Brisbane QD May 15 2007

Link State Routing Protocols Link-state routing protocols are also known as shortest path first protocols and are built around Edsger Dijkstra's shortest path first (SPF) algorithm. There are two link-state routing protocols for IP : OSPF(Open Shortest Path First) IS-IS(Intermediate-System-to-Intermediate-System)

Advantages of a Link State Routing Protocol Each router builds its own topological map of the network to determine the shortest path Immediate flooding of LSPs achieves faster convergence LSPs are sent only when there is a change in the topology and contain only the information regarding that change Hierarchical design used when implementing multiple areas

Basic Configuration and Goals Set the host name, and bring up the interfaces Configure the OSPF routing protocol Select the directly connected networks Display the routing table Display the OSPF protocol information

Configure Routers as the figure below

Verify that each router can ping its directly connected neighbors Queensland#ping 10.1.1.2 Queensland#ping 192.168.100.6 Darwin#ping 10.1.1.1 Adelaide#ping 192.168.100.5

Add OSPF to Queensland use the Process ID number 100 Queensland#config terminal Queensland(config)#router ospf 100 Queensland(config-router)#network 10.1.1.0 0.0.0.255 area 0 Queensland(config-router)#network 192.168.100.4 0.0.0.3 area 0

Add OSPF to Darwin use the Process ID number 100 Darwin#config terminal Darwin(config)#router ospf 100 Darwin(config-router)#network 10.1.1.0 0.0.0.255 area 0

Add OSPF to Adelaide use the Process ID number 100 Adelaide#config terminal Adelaide(config)#router ospf 100 Adelaide(config-router)#network 192.168.100.4 0.0.0.3 area 0

Test OSPF Routing OSPF should now be running on all three routers. Press CTRL+Z to exit to privileged mode, and can ping non-directly connected routers. From Darwin, and now be able to ping Adelaide’s serial 0 interface. Darwin#ping 192.168.100.6 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.100.6, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 62/62/63 ms

Test OSPF Routing Connect to Adelaide and ping Darwin’s serial 1 interface. If can ping on both devices, mean its correctly configured routing and otherwise Adelaide#ping 10.1.1.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 62/62/63 ms

Display the routing table on Darwin’s Router Darwin#sh ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is not set 10.0.0.0/24 is subnetted, 1 subnets C 10.1.1.0 is directly connected, Serial1/1 192.168.100.0/30 is subnetted, 1 subnets O 192.168.100.4 [110/1562] via 10.1.1.1, 00:16:14, Serial1/1

Display the Specific IP Routing Protocol Information on Darwin’s Router Darwin#show ip protocols Routing Protocol is "ospf 100" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 10.1.1.2 Number of areas in this router is 1. 1 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: 10.1.1.0 0.0.0.255 area 0 Routing Information Sources: Gateway Distance Last Update 10.1.1.1 110 00:17:05 Distance: (default is 110)

Display the OSPF Database on Darwin’s Router Darwin#show ip ospf database OSPF Router with ID (10.1.1.2) (Process ID 100) Router Link States (Area 0) Link ID ADV Router Age Seq# Checksum Link count 10.1.1.2 10.1.1.2 1228 0x80000002 0x00e13b 2 192.168.100.5 192.168.100.5 1072 0x80000008 0x00940b 4 192.168.100.6 192.168.100.6 1072 0x80000002 0x00ab5d 2

Display the all of IP OSPF Neighbors Darwin#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 192.168.100.5 0 FULL/ - 00:00:33 10.1.1.1 Serial1/1 Darwin#show ip ospf interface Serial1/1 is up, line protocol is up Internet address is 10.1.1.2/24, Area 0 Process ID 100, Router ID 10.1.1.2, Network Type POINT-TO-POINT, Cost: 781 Transmit Delay is 1 sec, State POINT-TO-POINT, Priority 0 No designated router on this network No backup designated router on this network Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:09 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1 , Adjacent neighbor count is 1 Adjacent with neighbor 192.168.100.5 Suppress hello for 0 neighbor(s)

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