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 areasshould be connected to the
backbone area. However, there may be instances whenan area will need to cross another
area to reach the backbone area like area 2 in thiscase. 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 thebackbone.
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-idvirtual-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 interfaceconfigured or can be manually set on the
neighboring router.