JNCIS-ENT: Juniper Networks Certified Specialist – Enterprise Routing and Switching (2025) — Question 13

Which two statements about BGP facilitate the prevention of routing loops between two autonomous systems? (Choose two.)

Answer options

• A. EBGP routers will append their AS number when advertising routes to their neighbors.
• B. EBGP routers will only accept routes that contain their own AS number in the AS_PATH.
• C. EBGP routers will drop routes that contain their own AS number in the AS_PATH.
• D. EBGP routers will prepend their AS number when advertising routes to their neighbors.

Correct answer: C, D

Explanation

The correct answers, C and D, are accurate because EBGP routers discard any routes that have their AS number in the AS_PATH, which prevents loops. Option A is incorrect as it describes appending the AS number rather than the correct action of prepending or discarding. Option B is also wrong because EBGP routers do not accept routes based on their own AS number being present, but rather they reject them.