Configure several experiments in a single OSPF area. 1. Configure the routing interface to start the OSPF process on R1, and configure the Router ID and the interface R1 (config) that runs OSPF) # router ospf 1R1 (config-router) # router-id 192.168.2.1R1 (config-router) # network 10.0.0.0 0.0.0.3 area 0R1 (config-router) # network worker 0.0.0 0.0.3 area 0 starts the OSPF process on R2, and configures the Router ID and the interface R1 (config) that runs OSPF # router ospf 1R1 (config-router) # router-id 192.168.1.1R1 (config-router) # network 192.168.1.1 0.0.0.0 area 0R1 (config-router) # netwo Rk 10.0.0.0 0.0.3 area 0 starts the OSPF process on R3, and configures the Router ID and the interface R1 (config) that runs OSPF # router ospf 1R1 (config-router) # router-id 192.168.3.1R1 (config-router) # network 192.168.3.1 0.0.0.0 area 0R1 (config-router) # network 255.0.0.0 0.0.3 area 0 on R1, loopback 192.168.2.1 is not declared in the ospf network, but loopback 192.168.1.1 is declared in the ospf network in the R2 configuration. Therefore, whether or not the loopback interface needs to enable ospf depends on the needs, however, no matter whether or not the loopback interface enables ospf, the IP address of the loopback interface can be a Router ID. Verify that R1 255.0.0.0/30 is subnetted, 1 subnetsC 255.0.0.0 is directly connected, FastEthernet0/0 10.0.0.0/30 is subnetted, 1 subnetsC 10.0.0.0 is directly connected, forward/0 192.168.1.0/32 is subnetted, 1 subnetsO 192.168.1.1 [110/2] via 10.0.0.1, 00:00:03, FastEthernet1/0 192.168.2.0/32 is subnetted, 1 subnetsC 192.168.2.1 is directly connected, Loopback0 192.168.3.0/32 is subnetted, 1 subnetsO 192.168.3.1 [110/2] via Route 0.0.2, 00:00:03, FastEthernet0/0R2 route 0.0.0/30 is subnetted, 1 subnetsO route 0.0.0 [110/2] via 10.0.0.2, 00:00:31, FastEthernet0/0 10.0.0.0/30 is subnetted, 1 subnetsC 10.0.0.0 is directly connected, FastEthernet0/0 192.168.1.0/32 is subnetted, 1 subnetsC 192.168.1.1 is directly connected, Loopback0 192.168.3.0/32 is subnetted, 1 subnetsO 192.168.3.1 [110/3] via 10.0.0.2, 00:00:31, FastEthernet0/0R3 255.0.0.0/30 is subnetted, 1 subnetsC 255.0.0.0 is directly connected, FastEthernet0/0 10.0.0.0/30 is subnetted, 1 subnetsO 10.0.0.0 [110/2] via 255.0.0.1, 00:01:00, fastEthernet0/0 192.168.1.0/32 is subnetted, 1 subnetsO 192.168.1.1 [110/3] via region 0.0.1, 00:01:00, FastEthernet0/0 192.168.3.0/32 is subnetted, 1 subnetsC 192.168.3.1 is directly connected, loopback0 experiment 2lo 0 do Router ID lo 1 simulate the interface configuration of the computer under the router with the computer omitted R1 (config) # router ospf 1R1 (config-Router) # router-id 1.1.1.1R1 (config-router) # network 1.1.1.1 0.0.0.0 area 0R1 (config-router) # network 192.168.1.0 0.0.255 area 0R1 (config-router) # network 10.1.1.0 0.0.0.3 area 0 can also be written as network 10.0.0.0 0.20.255.255 area 0R1 (config-router) # network 40.4.4.0 0.0.0.3 area 0 R2 (config) # router ospf 1R2 (config-router) # router-id 2.2.2.2R2 (config-router) # network 2.2.2.2 0.0.0.0 area 0R2 (config-router) # network 192.168.2.0 0.0.0.255 area 0R2 (config-router) # network 10.1.1.0 0.0.0.3 area 0R2 (config-router) # network route 2.2.0 0.0.0.3 area 0R2 route tag can be written as network 0.0.0.0 255.255.255.255 area 0 R3 (config) # router ospf 1R3 (config-router) # router ospf 1R3 (config-router) # network 3.3.3.3 0.0.0.0 area 0R3 (config-router) # network 192.168.3.0 0.0.255 area 0R3 (config-router) # network expansion 2.2.0 0.0.0.3 area 0R3 (config-router) # network 30.3.3.0 0.0.0.3 area 0 R4 (config) # router ospf 1R4 (config-router) # router-id 4.4.4.4R4 (config-router) # network 4.4.4.4 0.0.0.0 area 0R4 (config-router) # network 192.168.4.0 0.0.0.255 area 0R4 (config-router) # network 40.4.4.0 0.0.0.3 area 0R4 (config-router) # network 30.3.3.0 0.0.0.3 area 0 ends