350-401 Question 450
Select 2A network engineer is designing an OSPF network for an organization with multiple areas. The topology consists of Area 0 (backbone area), Area 1, and Area 2. One router serves as a connection between Area 0 and Area 1, while another router connects Area 0 to an external network running BGP. Which of the following correctly identifies the roles of these routers?
- A
The router connecting Area 0 and Area 1 is an Area Border Router (ABR).
- B
The router connecting Area 0 and the external BGP network is an Autonomous System Boundary Router (ASBR).
- C
The router connecting Area 0 and Area 1 is an Internal Router.
- D
The router connecting Area 0 and the external BGP network is a Backbone Router.
- E
The router connecting Area 0 and Area 1 is an ASBR.
Show answer and explanation
Correct answers: A, B
Explanation
In an OSPF network, specific router roles are defined based on their function. An ABR connects the backbone area (Area 0) to other areas, while an ASBR connects the OSPF domain to external routing domains (e.g., BGP). In this scenario, the router connecting Area 0 and Area 1 is an ABR, and the router connecting Area 0 to the external BGP network is an ASBR. Understanding these roles is critical for designing and troubleshooting OSPF networks.
- A. Correct.
Correct. An Area Border Router (ABR) connects the backbone area (Area 0) to another area, in this case, Area 1.
- B. Correct.
Correct. An Autonomous System Boundary Router (ASBR) is responsible for connecting an OSPF domain to an external network, such as BGP in this scenario.
- C. Incorrect.
Incorrect. An Internal Router is a router entirely within one OSPF area. The router connecting Area 0 and Area 1 spans multiple areas, so it cannot be classified as an Internal Router.
- D. Incorrect.
Incorrect. While the router connecting to the external BGP network is within the backbone area, its primary role is as an ASBR, not just a Backbone Router.
- E. Incorrect.
Incorrect. The router connecting Area 0 and Area 1 is not an ASBR because it does not connect to an external network; it connects two OSPF areas.