Which statement best describes how BGP attributes influence path selection?

• A. BGP relies on a single numeric metric to choose routes.
• B. BGP uses multiple attributes and policies to determine the best path.
• C. BGP ignores AS-path length in decisions.
• D. BGP uses only the origin code to select best path.

Answer: (B)

BGP path selection is driven by multiple attributes and operator-defined policies, not by a single numeric metric. Each route advertisement carries a set of attributes, and the router applies a defined decision process to choose the best path. For example, the local preference value set within an AS can steer outbound traffic by making routes with higher local preference more favorable. If that preference ties, the router compares the AS_PATH length, preferring the shorter sequence of AS hops. Origin type also matters as a tie-breaker, with IGP-originated routes generally preferred over EGP or unknown origins. The Multi-Exit Discriminator (MED) provides an inbound traffic hint and is considered next in the decision sequence. Beyond these, whether a route is learned via eBGP versus iBGP influences preference, and the reachability and internal metric to the next hop can further differentiate candidates. All of these factors can be shaped by policies, such as route-maps or prefix lists, which modify attributes to meet routing goals. This combination of attributes and policies is why BGP does not rely on a single metric or a single attribute.

The other statements don’t fit because BGP does not use just one numeric metric, and it does consider AS_PATH length as part of the decision process. It also does not rely solely on the origin code to select the best path.