Exam 200-301 topic 1 question 364 discussion

When IOS must choose between routes learned using different routing protocols, IOS uses a concept called administrative distance. Administrative distance is a number that denotes how believable an entire routing protocol is on a single router. The lower the number, the better The AD is a rating of trust when multiple routes exist to the same destination.

To my understanding If installing into routing table is AD or Metric ONLY! If choosing a route from routing table is Longest Prefix, AD & Metric. Basically all are taken into account. AD - When 2 or more routes to the same destination from different routing protocols Metric - When 2 or more routes to the same destination and using the SAME ROUTING PROTOCOL Longest Prefix(in the case when choosing a route from route table)- This will take precedence over AD and Metric Hope everyone gets the idea on how routing questions work. Also take into account that you should also know if the subnet prefix can be used for the host that the route we are choosing.

C is correct

C is correct -AD

Administrative distance is the correct answer

When it comes to chose one route from many that ALREADY EXISTS in RIB to same destination, router uses longest prefix match rule. AD (Administrative Distance) is used when it comes to installing different paths learned through different protocols. Hence, in my opinion the "Longest Prefix Match" answer is missing.