What is the primary function of Split Horizon in routing?

The primary function of Split Horizon in routing is to prevent routing loops. This method works primarily in distance-vector routing protocols, where routing information can be shared between routers. When a router learns about a route from a neighboring router, Split Horizon dictates that this router should not send information about that route back to the neighbor from which it learned it. By implementing this strategy, Split Horizon effectively reduces the possibility of routing loops, which can cause erratic network behavior and unnecessary traffic as routers continuously inform each other about routes that are no longer valid.

Routing loops can lead to a situation where data packets circulate endlessly between routers, causing network congestion and performance degradation. By using Split Horizon, the routing tables are kept more stable and accurate, thereby ensuring more reliable data transmission between devices within the network.

The other choices, although they address various aspects of network routing, do not align with the primary purpose of Split Horizon. For instance, increasing the speed of routing updates, reducing the number of routes in a network, or enhancing encryption in network traffic are not functionalities associated with Split Horizon. Instead, the focus is distinctly on the prevention of routing loops, making option B the correct choice.