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 20.20.20.1, 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 30.30.30.3
R3(config-router)# area 1 virtual-link 20.20.20.1
B.
R1(config-router)# area 1 virtual-link 20.20.20.2
R3(config-router)# area 1 virtual-link 30.30.30.2
C.
R1(config-router)# area 0 virtual-link 1.1.1.1
R3(config-router)# area 2 virtual-link 3.3.3.3
D.
R1(config-router)# area 1 virtual-link 3.3.3.3
R3(config-router)# area 1 virtual-link 1.1.1.1
E.
R1(config-router)# area 1 virtual-link 2.2.2.2
R3(config-router)# area 1 virtual-link 2.2.2.2
Explanation:
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 virtual-link
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.