What is Metric?

Metric is numeric value used to calculate the best path to the destination. The lowest metric value is considered as best route to the destination. The metric calculation varies based on the type of protocol.

lets take RIP protocol for example,

The RIP protocol calculates metric based on hop count(0-15). To reach a destination one route has metric value 3 and one more route has metric value 5, The route with metric 3 is choosed as best path to reach destination.