Within an OSPF area, routers are divided into the following
—A router with that has OSPF neighbor
relationships only with devices in the same area.
Area Border Router (ABR)
—A router that has OSPF neighbor
relationships with devices in multiple OSPF areas. ABRs gather topology information
from their connected areas and distribute it to the backbone area.
—A backbone router is a router that
runs OSPF and has at least one interface connected to the OSPF backbone
area. Since ABRs are always connected to the backbone, they are
always classified as backbone routers.
Autonomous System Boundary Router (ASBR)
—An ASBR is
a router that attaches to more than one routing protocol and exchanges routing
information between them.