What Is Metric?

Metrics are the fuel that powers your network's engine, like the amount of gas in your tank, but for your data packets. They determine how far and fast you can go before you run out of gas. Metrics are variables that measure the quality of a route, and they're crucial to determining how well your packets will get where you want them to go. Metrics are calculated by looking at several factors, including the distance between two points, the number of steps needed to reach those points, and other things like topology (how many routes there are to choose from). The course with the lowest metric is usually the fastest way to get from A to B. A metric can be the number of steps you must take to reach your destination. Imagine you're on vacation and want to walk from your hotel room to the beach. You know that there are four flights of stairs between the two locations, so it would take four steps to get there. Now imagine that you're on a different vacation, and you must go from your hotel room to a restaurant down the street this time. You know that there is one flight of stairs between the two locations, but there are also two flights between where you start and where you finish, so it would take you three steps total to get there. In both cases, one flight of stairs takes one step; however, because there are fewer flights between your starting point and your ending point in the second scenario, it takes fewer steps overall (three) than in the first scenario (four). The metrics of a route are the number of hops or the number of routers, the source and the destination. The routing tables in routers contain only routes with the lowest metrics. There is another essential network attribute called link-state, which is used together with the metric to make the final decision regarding the best path. The only approach a router will accept into its routing table is the one with the lowest metric but that's not where the story ends. The other network attribute, called link-state, ensures that the path you want is the best for you and your network. Together with the metric, it determines which route will be accepted into the routing table.