Configuration of OSPF Routing Protocol in a single region

1. Topology


2. show run after configuration on each vro
A. r1 # show run
Building configuration...

Current configuration: 645 bytes
!
Version 12.4:
No service timestamps log datetime msec
No service timestamps debug datetime msec
No service password-encryption
!
Hostname r1
!
!
Www.2cto.com
Interface Loopback0
Ip address 11.11.1.1 255.255.255.0
!
Interface FastEthernet0/0
Ip address 172.16.123.1 255.255.255.0
Duplex auto
Speed auto
!
Interface FastEthernet0/1
Ip address 10.10.1.254 255.255.255.0
Duplex auto
Speed auto
!
Interface Vlan1
No ip address
Shutdown
!
Router ospf 100
Log-adjacency-changes
Network 172.16.123.1 0.0.0.0 area 0
Network 10.10.1.254 0.0.0.0 area 0
!
Ip classless
!
!
Line con 0
Line vty 0 4
Login
!
!
End Content B. r2 #
R2 # show run
Building configuration...

Current configuration: 666 bytes
!
Version 12.4:
No service timestamps log datetime msec
No service timestamps debug datetime msec
No service password-encryption
!
Hostname r2
!
!
Interface Loopback0
Ip address 22.22.2.2 255.255.255.0
!
Interface FastEthernet0/0
Ip address 172.16.123.2 255.255.255.0
Duplex auto
Speed auto
!
Interface FastEthernet0/1
Ip address 10.10.2.254 255.255.255.0
Duplex auto
Speed auto
!
Interface Vlan1
No ip address
Shutdown
!
Router ospf 100
Router-id 22.22.2.2
Log-adjacency-changes
Network 172.16.123.2 0.0.0.0 area 0
Network 10.10.2.254 0.0.0.0 area 0
!
Ip classless
!
!
Line con 0
Line vty 0 4
Login
!
!
End c.
Www.2cto.com r3 #
R3 # show run
Building configuration...

Current configuration: 645 bytes
!
Version 12.4:
No service timestamps log datetime msec
No service timestamps debug datetime msec
No service password-encryption
!
Hostname r3
!
!
Interface Loopback0
Ip address 33.33.3.3 255.255.255.0
!
Interface FastEthernet0/0
Ip address 172.16.123.3 255.255.255.0
Duplex auto
Speed auto
!
Interface FastEthernet0/1
Ip address 10.10.3.254 255.255.255.0
Duplex auto
Speed auto
!
Interface Vlan1
No ip address
Shutdown
!
Router ospf 100
Log-adjacency-changes
Network 172.16.123.3 0.0.0.0 area 0
Network 10.10.3.254 0.0.0.0 area 0
!
Ip classless
!
!
Line con 0
Line vty 0 4
Login
!
!
End
3. view the neighbor table, topology table, and route table
A. r1 # show ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
22.22.2.2 1 FULL/BDR 00:00:35 172.16.123.2 FastEthernet0/0
33.33.3.3 1 FULL/DROTHER 00:00:31 172.16.123.3 FastEthernet0/0
R1 # show ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
22.22.2.2 1 FULL/BDR 00:00:30 172.16.123.2 FastEthernet0/0
33.33.3.3 1 FULL/DROTHER 00:00:36 172.16.123.3 FastEthernet0/0
R1 # show ip route
Codes: C-connected, S-static, I-IGRP, R-RIP, M-mobile, B-BGP
D-OSPF, EX-VPN 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, L1-IS level-1, L2-IS level-2, ia-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, 3 subnets
C 10.10.1.0 is directly connected, FastEthernet0/1
O 10.10.2.0 [110/2] via 172.16.123.2, 00:06:07, FastEthernet0/0
O 10.10.3.0 [110/2] via 172.16.123.3, 00:05:57, FastEthernet0/0
11.0.0.0/24 is subnetted, 1 subnets
C 11.11.1.0 is directly connected, Loopback0
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.123.0 is directly connected, FastEthernet0/0
R1 # B. r2 # show ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
11.11.1.1 1 FULL/DR 00:00:38 172.16.123.1 FastEthernet0/0
33.33.3.3 1 FULL/DROTHER 00:00:31 172.16.123.3 FastEthernet0/0
R2 # show ip ospf data
OSPF Router with ID (22.22.2.2) (Process ID 100)

Router Link States (Area 0)

Link id adv Router Age Seq # Checksum Link count
172.16.123.1 172.16.123.1 2475 0x80000003 0x0055f2 2
172.16.123.2 172.16.123.2 1926 0x80000005 0x006ed2 2
172.16.123.3 172.16.123.3 1651 0x80000007 0x0087b2 2
22.22.2.2 22.22.2.2 489 0x80000007 0x0063f0 2
11.11.1.1 11.11.1.1 489 0x80000007 0x003254 2
33.33.3.3 33.33.3.3 469 0x80000003 0x009c89 2

Net Link States (Area 0)
Link id adv Router Age Seq # Checksum
172.16.123.1 11.11.1.1 469 0x80000004 0x00fd41
R2 # show ip route
Codes: C-connected, S-static, I-IGRP, R-RIP, M-mobile, B-BGP
D-OSPF, EX-VPN 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, L1-IS level-1, L2-IS level-2, ia-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, 3 subnets
O 10.10.1.0 [110/2] via 172.16.123.1, 00:07:57, FastEthernet0/0
C 10.10.2.0 is directly connected, FastEthernet0/1
O 10.10.3.0 [110/2] via 172.16.123.3, 00:07:47, FastEthernet0/0
22.0.0.0/24 is subnetted, 1 subnets
C 22.22.2.0 is directly connected, Loopback0
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.123.0 is directly connected, FastEthernet0/0
R2 # c. r3 # show ip ospf nei

Neighbor ID Pri State Dead Time Address Interface
22.22.2.2 1 FULL/BDR 00:00:33 172.16.123.2 FastEthernet0/0
11.11.1.1 1 FULL/DR 00:00:37 172.16.123.1 FastEthernet0/0
R3 # show ip ospf data
OSPF Router with ID (33.33.3.3) (Process ID 100)

Router Link States (Area 0)

Link id adv Router Age Seq # Checksum Link count
172.16.123.1 172.16.123.1 2546 0x80000003 0x0055f2 2
172.16.123.2 172.16.123.2 1997 0x80000005 0x006ed2 2
172.16.123.3 172.16.123.3 1722 0x80000007 0x0087b2 2
22.22.2.2 22.22.2.2 560 0x80000007 0x0063f0 2
11.11.1.1 11.11.1.1 560 0x80000007 0x003254 2
33.33.3.3 33.33.3.3 540 0x80000003 0x009c89 2

Net Link States (Area 0)
Link id adv Router Age Seq # Checksum
172.16.123.1 11.11.1.1 540 0x80000004 0x00fd41
R3 # show ip route
Codes: C-connected, S-static, I-IGRP, R-RIP, M-mobile, B-BGP
D-OSPF, EX-VPN 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, L1-IS level-1, L2-IS level-2, ia-IS inter area
*-Candidate default, U-per-user static route, o-ODR
P-periodic downloaded static route
Www.2cto.com
Gateway of last resort is not set

10.0.0.0/24 is subnetted, 3 subnets
O 10.10.1.0 [110/2] via 172.16.123.1, 00:08:59, FastEthernet0/0
O 10.10.2.0 [110/2] via 172.16.123.2, 00:08:59, FastEthernet0/0
C 10.10.3.0 is directly connected, FastEthernet0/1
33.0.0.0/24 is subnetted, 1 subnets
C 33.33.3.0 is directly connected, Loopback0
172.16.0.0/24 is subnetted, 1 subnets
C 172.16.123.0 is directly connected, FastEthernet0/0
R3 #
Note: In the Packet Tracer environment, If you do not configure the router-id before configuring the loopback 0 IP address, the loopback address will not automatically become the router-id. After saving the configuration, run the reload command to restart the vro.