Which type of router is specific to a multiarea OSPF design?
- ASBR
- ABR
- internal router
- backbone router
Explanation: The Area Border Router (ABR) is the specific type of router required for a multiarea OSPF design because its primary function is to connect multiple areas together. An ABR maintains a separate Link-State Database (LSDB) for each area it is connected to and is responsible for summarizing routing information between those areas.
In contrast, the other router roles can exist in both single-area and multiarea designs:
- Internal Router: These routers have all their interfaces in a single area. In a single-area design, every router is an internal router.
- Backbone Router: These are routers with at least one interface in Area 0. If a single-area design uses Area 0, all routers in that design are backbone routers.
- ASBR (Autonomous System Boundary Router): This router connects the OSPF domain to external routing domains (like the internet or another routing protocol). An ASBR can reside within a single-area OSPF network.
Therefore, while internal, backbone, and ASBR routers are often part of a multiarea OSPF network, only the ABR is fundamentally unique to and required by a design involving more than one area.
Related exam: Modules 8 – 13: Checkpoint Exam: Network Routing Answers (CCNP ENCOR v9)
