In BGP policy, what can an AS influence?

• A. How your traffic gets to a neighboring AS
• B. Which peer you connect to
• C. How your traffic is treated inside neighboring AS
• D. The global Internet policy

Answer: (A)

In BGP policy, the thing you can influence is the path that your traffic takes toward a neighboring AS. This is done by shaping which routes you advertise and accept, and by setting route attributes that other networks use to decide which path to prefer. For example, you can raise local preference on routes learned from a preferred neighbor, prepend your AS path to make a certain path seem longer and less attractive, or set MED values and tag routes with communities to guide upstream decisions. These mechanisms let you steer outbound traffic toward a chosen exit point or influence inbound traffic coming from other networks based on the routes you publish.

The other aspects aren’t driven by BGP policy in the same way. Deciding which peer to connect to is a configuration/peering decision rather than a policy outcome, so it isn’t what BGP policy primarily controls. You also can’t control how traffic is treated inside another AS—that’s up to that neighbor’s internal policies. And global Internet policy sits outside your own routing policies.