JNCIS-SP: Juniper Networks Certified Specialist – Service Provider Routing (2022) — Question 43

What is the correct description of an Area Border Router (ABR)?

Answer options

• A. An ABR is an OSPF router with links in two areas, connecting OSPF areas to the backbone
• B. An ABR is an OSPF router that injects routing information from outside the OSPF AS
• C. An ABR is an OSPF router with at least one link in a Layer 2 area
• D. An ABR is an OSPF router with all of its links within an area

Correct answer: A

Explanation

The correct answer is A because an Area Border Router (ABR) indeed connects two OSPF areas to the backbone area. Option B is incorrect as it describes an ASBR, which is responsible for injecting external routing information into OSPF, while options C and D mischaracterize the function and structure of an ABR, as they do not accurately reflect its role in connecting different OSPF areas.