300-440 Question 97
Single answerA network engineer is configuring OSPF in a multi-area environment. Area 0 is the backbone area, and Area 1 is configured as a Totally Stubby Area. The engineer needs to ensure that Area 1 does not receive external routes or inter-area routes, except for the default route. Which router type must be configured to enforce this behavior?
- A
Area Border Router (ABR)
- B
Autonomous System Boundary Router (ASBR)
- C
Internal Router
- D
Backbone Router
Show answer and explanation
Correct answer: A
Explanation
To configure a Totally Stubby Area in OSPF, an Area Border Router (ABR) is required. The ABR connects the backbone area (Area 0) to other areas and can suppress inter-area and external routes from being advertised into the stub area, leaving only a default route. This behavior is essential for the Totally Stubby Area's design to minimize routing overhead within the area.
- A. Correct.
The Area Border Router (ABR) is responsible for connecting different OSPF areas and can enforce specific area types, such as Totally Stubby Areas, by controlling the types of routes advertised into the area.
- B. Incorrect.
The Autonomous System Boundary Router (ASBR) injects external routes into the OSPF domain but does not control area-specific configurations like Totally Stubby Areas.
- C. Incorrect.
An Internal Router operates entirely within a single OSPF area and does not have the capability to enforce area-specific configurations or route filtering.
- D. Incorrect.
The Backbone Router is any router that has at least one interface in Area 0. While it may participate in inter-area routing, it does not have the ability to enforce Totally Stubby Area configurations.