You can configure a virtual link to define an OSPF virtual link and its related parameters. In OSPFv3, all areas must be connected to a backbone area. If there is a break in backbone continuity, or the backbone is purposefully partitioned, a virtual link can be established. The two endpoints of a virtual link are ABRs. The virtual link must be configured in both routers.
The configuration information in each router consists of the other virtual endpoint (the other ABR) and the non-backbone area that the two routers have in common (called the transit area).
See Virtual Link and Route Summarization Topology for the topology for configuring and testing virtual link and route summarization.