Determining the Best Path for Packets

B

When a router receives a packet with multiple possible paths to the destination over different routing protocols, it chooses the best path based on administrative distance and metric.

Administrative distance is a measure of the reliability of a routing protocol. It is a value between 0 and 255, where a lower value indicates a more reliable protocol. Each routing protocol has a default administrative distance, but it can be manually configured if necessary.

Metric is a value that represents the cost of the path to the destination. The lower the metric, the better the path. Each routing protocol uses a different metric, but the most common ones are hop count, bandwidth, delay, and load.

Based on these criteria, the router chooses the path with the lowest administrative distance and the lowest metric. However, if two paths have the same administrative distance, the router chooses the path with the lowest metric. If two paths have the same metric, the router load balances between them.

Therefore, the correct answer to this question is option D: the router chooses the path with both the lowest administrative distance and the lowest metric. This ensures that the path selected is both reliable and efficient.