350-401 Question 437
Single answerYou are configuring OSPF on a multi-area network. The network consists of the following components: a backbone area (Area 0), a standard area (Area 1), and a totally stubby area (Area 2). One router is responsible for connecting Area 1 and Area 2 to the backbone area. Which type of router is responsible for this role in the OSPF design?
- A
Internal Router
- B
Backbone Router
- C
Area Border Router (ABR)
- D
Autonomous System Boundary Router (ASBR)
Show answer and explanation
Correct answer: C
Explanation
In OSPF design, an Area Border Router (ABR) is responsible for connecting multiple OSPF areas, including the backbone area (Area 0) and other non-backbone areas. In this scenario, the router that connects Area 1 and Area 2 to the backbone (Area 0) is an ABR. ABRs are critical for propagating routing information between areas while maintaining hierarchical segmentation in OSPF.
- A. Incorrect.
An Internal Router resides entirely within a single OSPF area and does not connect multiple areas. This is incorrect for the described scenario.
- B. Incorrect.
A Backbone Router is any router located within Area 0 (the backbone area). While this router may exist in the backbone, it does not perform the role of connecting multiple areas.
- C. Correct.
An Area Border Router (ABR) connects OSPF areas, including the backbone area (Area 0) and non-backbone areas (Area 1 and Area 2). This matches the described role in the question.
- D. Incorrect.
An Autonomous System Boundary Router (ASBR) connects an OSPF domain to an external routing domain (e.g., another routing protocol). This is not relevant to the scenario, as no external domain is mentioned.