Question

A service provider's OSPF network has area 0 partitioned into two segments because a WAN link between two backbone routers (R1 and R4) failed and cannot be restored quickly. R1 connects to area 0 segment A, and R4 connects to area 0 segment B. Both R1 and R4 also connect to area 10, which is fully operational and provides an alternate transit path between the two backbone segments. Which configuration restores backbone connectivity without renumbering areas or waiting for the WAN repair?

Accepted Answer

Configure an OSPF virtual link between R1 and R4 through area 10, using each other's router IDs

Answer

Configure area 10 as a stub area on both R1 and R4 to force traffic through the backbone

Answer

Configure a sham link between R1 and R4 across area 10 to bridge the backbone segments

Answer

Redistribute area 10 routes into area 0 on both R1 and R4 using a route map