An administrator Pipes in the command router ospf 1 and receives the error message: “OSPF process 1 cannot start.” (Output is omitted.) What should be done to correctly set up OSPF?
A – Ensure that an interface has been configured with an IP address
B – Ensure that an interface has been configured with an IP address and is up
C – Ensure that IP classless is enabled
D – Ensure that the interfaces can ping their directly connected neighbors
During a recent OSPF election among three routers. RTA was elected the DR and RTB was elected the BDR, as seen in the graphic. Assume that RTA fails, and that RTB takes the place of the DR while RTC becomes the new BDR. What will happen when RTA comes back online?
A – RTA will take the place of DR immediately upon establishing its adjacencie
B – RTA will take the place of DR only if RTB fails
C – RTA will take the place of DR only if both RTB and RTC fail
D – A new election will take place establishing an all new DR and BDR based on configured priority levels and MAC addresses
Refer to the exhibit. During the process of configuring a virtual link to connect area 2 with the backbone area, the network administrator received this console message on R3:
*Mar 1 00:25:01.084: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual link but not found from 188.8.131.52, Serial 0
How should the virtual link be configured on the OSPF routers to establish full connectivity between the areas?
A – R1(config-router)# area 1 virtual-link 184.108.40.206
R3(config-router)# area 1 virtual-link 220.127.116.11
B – R1(config-router)# area 1 virtual-link 18.104.22.168
R3(config-router)# area 1 virtual-link 22.214.171.124
C – R1(config-router)# area 0 virtual-link 126.96.36.199
R3(config-router)# area 2 virtual-link 188.8.131.52
D – R1(config-router)# area 1 virtual-link 184.108.40.206
R3(config-router)# area 1 virtual-link 220.127.116.11
E – R1(config-router)# area 1 virtual-link 18.104.22.168
R3(config-router)# area 1 virtual-link 22.214.171.124
When designing a multi-area OSPF network, all areas should be connected to the backbone area. However, there may be instances when an area will need to cross another area to reach the backbone area like area 2 in this case. A virtual link has the following two requirements:
+ It must be established between two routers that share a common area and are both ABRs.
+ One of these two routers must be connected to the backbone.
In this case, two routers that satisfy the above requirements are R1 and R3. The syntax for creating a virtual link across an area is:
area area-id virtual-link neighbor-router-id
The area-id is the number of the transit area, in this example Area 1 and neighbor-router-id is the IP address of the highest loopback interface configured or can be manually set on the neighboring router.