What distance vector feature prevents a routing protocol from advertising learned routes from the same interface?

The feature that prevents a routing protocol from advertising learned routes from the same interface is split horizon. This mechanism is essential in distance vector routing protocols, as it helps to prevent routing loops and enhances network stability.

When a router receives route updates over a specific interface, it should not send those same updates back out through the same interface. This means that, if a router learns of a route from a particular interface, it will not advertise that route back out through that same interface. This prevents the possibility of a situation where routing loops could occur, where routers continuously advertise the same routes back and forth.

For instance, if Router A learns about a route to a certain destination from Router B through Interface 1, it will refrain from sending this information back to Router B through Interface 1. Instead, Router A would only use that route for its routing table operations but not share it back out to Router B.

The other options—route summarization, hold-down timers, and triggered updates—serve different purposes in distance vector protocols. Route summarization simplifies routing tables by combining several routes into a single advertisement. Hold-down timers help stabilize the convergence process by preventing updates about routes from being accepted too quickly after a route has been deemed unreachable. Triggered updates allow