What does the split horizon rule accomplish?

The split horizon rule is a key principle in distance-vector routing protocols, primarily aimed at preventing routing loops and ensuring the stability of the routing tables. Its main function is to prevent a router from advertising a route back to the source from which it learned about that route. This means that if a router learns about a particular route from a neighboring router, it will not send updates about that route back to that neighbor. By doing this, the split horizon rule helps to mitigate the potential for routing loops that can occur when routing information circulates indefinitely among routers.

This rule effectively stabilizes route determination and reduces the chances of miscommunication within the network, ensuring that each router only shares useful and relevant routing information with its neighbors.

The other choices relate to other aspects of routing mechanisms but do not accurately define the function of the split horizon rule. For instance, limiting the number of hops is tied more to maximum hop count configurations or other protocols like route poisoning. Improving the speed of route discovery and decreasing network traffic through aggregation focus on optimizing how routing information is processed or minimized rather than the specific aim of preventing loops, which is the core purpose of the split horizon rule.