Failed to establish adjacency after configuring Stub on the router

After the router is configured with Stub

Failed to establish adjacency

As shown in figure 11.1, the head office and branch of BENET are connected through an E1 dedicated line. R1 and R2 are head office routers, and R3 is branch routers. The network plan is as follows:

The interconnection address of n R1 and R2 is: 10.0.0.0 Universe 30. The interconnection address of R2 and R3 is: 20.0.0.0 Universe 30.

N use the Loopback0 interface address of the router as the Loopback0:3.3.3.3/32 of the Loopback0:2.2.2.2/32,R3 of the Loopback0:1.1.1.1/32,R2 of Route-id,R1.

Figure 11.1 after configuring Sutb, the adjacency cannot establish the network diagram

After completing the configuration, the network engineer found that R2 and R3 could not form an adjacency, and the router OSPF configuration was as follows (the interface was correctly configured and omitted).

R1 configuration

Router ospf 1

Router-id 1.1.1.1

Network 1.1.1.1 0.0.0.0 area 0

Network 10.0.0.0 0.0.0.3 area 0

R2 configuration

Router ospf 1

Router-id 2.2.2.2

Network 2.2.2.2 0.0.0.0 area 0

Network 10.0.0.0 0.0.0.3 area 0

Network 20.0.0.0 0.0.0.3 area 1

R3 configuration

Router ospf 1

Router-id 3.3.3.3

Area 1 stub

Network 3.3.3.3 0.0.0.0 area 0

Network 20.0.0.0 0.0.0.3 area 1

First, check that the network link of the device is normal, and use the ping command to check connectivity

Then, the port state is built with the show intface f0amp 0 and show ip ospf interface FastEthernet 0ramp 0 commands. If the ports and links are normal, you need to consider the relevant configuration of the OSPF. Check the configuration and find that the R3 router is configured as a stub area, while the rest of the stub routers cannot establish adjacencies with other routers in non-stub areas.

Finally, check that the area type of the configured R3 router is configured as stub and the R2 router Area1 is a standard area, resulting in an adjacency that cannot be established. After changing the area type of the R3 router to a standard area, troubleshoot.