A. Area Border Router
B. Auxiliary System Border Router
C. Area System Border Router
D. Autonomous System Boundary Router
Correct Answer: D
ASBR (Autonomous System Boundary Router) – Connects the OSPF backbone to external networks. Routers that inject external LSAs into the OSPF database
Any router whose interfaces all belong to the same OSPF area. These routers keep only one linkstate database.
Routers that are connected to more than one area. These routers maintain a link-state database for each area they belong to. These routers generate summary
Routers that inject external LSAs into the OSPF database (redistribution). These external routes are learned via either other routing protocols or static routes.
Routers with at least one interface attached to Area 0.
Tip: An OSPF router can be an ABR, an ASBR, and a backbone router at the same time. The router is an ABR if it has an interface on Area 0 and another
interface in another area. The router is a backbone router if it has one or more interfaces in Area 0. The router is an ASBR if it redistributes external routes into the