Distance Vector Routing Protocol Features and Loop Prevention

Distance Vector Routing Protocol (DVRP) is a type of routing protocol that determines the best path to a destination network based on the distance or vector and the number of hops away from the destination. DVRPs use a metric to evaluate the distance or cost of each path, and they update and exchange their routing tables periodically.

One of the primary features of DVRPs is that they are easy to configure and manage. They are also scalable, making them ideal for smaller networks. DVRPs are efficient at routing traffic but have some limitations, particularly in larger networks.

To prevent loops in DVRPs, several techniques can be used. Split horizon is a method that prevents a router from advertising a route back to the interface where it was learned. Poison reverse is a technique where a router sends an infinite metric for a route back to the router where it learned about the route. Hold-down timers are used to prevent a router from accepting route updates for a specific period of time after it has received notification that a route is no longer valid.

Administrative distance (AD) is a value that routers use to select the best path to a destination when there are multiple paths available from different routing protocols. It is a numerical value assigned to each routing protocol, and it is used to determine the reliability of the routing information. The lower the AD, the more reliable the information. For example, a directly connected network has an AD of 0, while a static route has an AD of 1. If multiple routing protocols provide routes to the same destination network, the router will select the path with the lowest AD.