The router links are an indication of the state of the interfaces on a router belonging to a certain area. Each router will generate a router link for all of its interfaces. Summary links are generated by ABRs; this is how network reachability inform...
http://www.ebrahma.com/2013/10/how-to-configuring-multi-area-ospf/Labels: ABRs, ASBR, bdr, Designated-Router, Ethernet, multi-access, Multi-Area-OSPF, NBMA, Network-Links, OSPF, Router-(DR), Token-Ring-and-FDDI