What is the AD for Internal BGP routes?

The correct answer is that the administrative distance (AD) for Internal BGP (iBGP) routes is 200. In the context of routing protocols, administrative distance is a value that is used by routers to determine the trustworthiness of the route information received from different routing protocols. It serves as a ranking system, allowing routers to choose the best route when multiple paths to the same destination are available.

Internal BGP is used to exchange routing information between routers within the same autonomous system. To prioritize the use of internal BGP routes over external routes from other protocols, iBGP is assigned a higher administrative distance of 200. This means that if a router receives route updates through iBGP, it will consider these routes less preferred than those received from other source protocols like EIGRP (which has an AD of 90) and OSPF (which has an AD of 110), thereby aligning with the hierarchical structure of route priorities.

Understanding the administrative distances is crucial when designing and troubleshooting network routing, as it affects how routing decisions are made and how traffic is directed through a network.