JNCIS-ENT: Juniper Networks Certified Specialist – Enterprise Routing and Switching (2025) — Question 27

Your BGP router receives routes from two upstream ISPs: ISP A and ISP B.
In this scenario, which change would you make to prefer routes from ISP A?

Answer options

• A. Set the local-preference attribute for all routes received from ISP A to 200 while all routes received from ISP B use the default local-preference value of 100.
• B. Prepend the AS path to all routes received from ISP A while all routes received from ISP B use the default AS path value.
• C. Change the MED value for all routes received from ISP A to 1 while all routes from ISP B remain configured with no MED value.
• D. Set the local-preference attribute for all routes received from ISP A to 50 while all routes received from ISP B use the default local-preference value of 100.

Correct answer: A

Explanation

The correct answer is A because setting a higher local-preference value for ISP A's routes directly influences the BGP decision process, making those routes more preferred. Options B and C do not affect local preference and would not achieve the desired outcome. Option D uses a lower local-preference value for ISP A, which would actually make routes from ISP B more preferred, contrary to the requirement.