Ospf Virtual Circuit

Ospf Virtual Circuit
WKiom1ZYU52D5vxjAAD-9Ow8cic029.png1. configure the IP addresses of each vro and run the ping command to check the connectivity of the direct connection ports of each vro2. first, configure the ospf protocol of R2, R3, and R4. During configuration, pay attention to Area 3. after the configuration is complete, check the R1 route table R1 # sho ip routeGateway of lastresort is not set 172.16.0.0/16 is variably subnetted, 6 subnets, 3 masksC 172.16.1.0/24 is directly connected, loopback0L 172.16.1.1/32 is directly connected, Loopback0C 172.16.255.0/30 is directly connected, Serial1/0L 172.16.255.1/32 is directly conn Ected, Serial1/0O IA 172.16.20.4/30 [110/128] via172.16.255.2, 00:00:49, Serial1/0 R1 only learns routes of area2 4. view R2 route R2 # sho ip routeGateway of lastresort is not set 172.16.0.0/16 is variably subnetted, 6 subnets, 3 masksO 172.16.1.1/32 [110/65] via172.16.255.1, 00:02:08, serial1/0 R2 only learns routes C 172.16.255.0/30 is directly connected, Serial1/0L 172.16.255.2/32 is directly connected, Serial1/0C 172.16.255.4 /30 is directly connected, Serial1/1L 172.16.20.5/32 is directly connected, Serial1/15. view R3 route # sho ip routeGateway of lastresort is not set 172.16.0.0/16 is variably subnetted, 5 subnets, 3 masksO IA 172.16.16.1/32 [110/65] via 172.16.20.10, 00:04:49, serial1/1 R3 only learns area 1 route C 172.16.255.0/24 is directly connected, Serial1/1 is directly connected, Serial1/0L 172.16.4266/32 is directly connected, Ser Ial1/0L 172.16.20.9/32 is directly connected, Serial1/1 6. view the R4 route # sho ip routeGateway of lastresort is not set 172.16.0.0/16 is variably subnetted, 5 subnets, 3 masksC 172.16.16.0/24 is directly connected, loopback0L 172.16.16.1/32 is directly connected, Loopback0C 172.16.255.0/24 is directly connected, Serial1/0O IA 172.16.20.4/30 [110/192] via 172.16.20.9, 00:02:59, serial1/0 R4 only learns the routing of area 2 L 172. 16.20.10/32 is directly connected, Serial1/0 7. Through the above view, it is found that no router can learn the complete network route. The main cause of this problem is that the backbone area is separated by area2, and the entire network becomes two ospf autonomous systems. Therefore, they cannot learn complete routes between each other. in this case, you can configure a virtual circuit to solve the problem of splitting the backbone areas. The following configuration is implemented on the routes of R2 and R3: R2 (config) # routerospf 1R2 (config-router) # area2 virtual-link 172.16.20.9 create a virtual circuit. area 2 in the command indicates that a virtual circuit exists in area 2. Vritual-link 172.16.20.9 indicates the router id of the Peer R3 router that creates the virtual circuit. R3 (config) # routerospf 1R3 (config-router) # area2 virtual-link 172.16.20.5 configure the virtual circuit 9 of the R2 router, view any vro, and confirm the route learning status, r1 # sho iproute Gateway of last resort is not set 172.16.0.0/16 is variably subnetted, 6 subnets, 3 masksC 172.16.1.0/24 is directly connected, Loopback0L 172.16.1.1/32 is directly connected, loopback0O IA 172.16.255.0/24 [110/192] via172.16.255.2, 00:30:21, Serial1/0O 172.16.20.8/30 [110/128] v Success, 00:14:19, Serial1/0 C 172.16.255.0/30 is directly connected, Serial1/0L 172.16.255.1/32 is directly connected, Serial1/0O IA 172.16.16.1/32 [110/193] via 172.16.255.2, 00:30:21, serial1/0 now R1 has learned the complete network route. 10. At this time, the failure to learn the complete routing problem has been solved. Ospf Vritual-link not only solves the problem of direct connection between common areas and backbone areas, but also solves the problem that the backbone is separated. However, this type of problem is generally caused by network migration or design issues. The ospf Virtual circuit is just a solution for network transition.