Question

What is a metric in a routing protocol? What is a metric used for? List and describe two major metrics used in routing protocols.

Answer 1

Metric is like an algorithm which is used by a router to decide the best and most optimum path to the destination from the source. Metric is a network variable whose behavior depends largely on the routing protocol associated with it. For example, some routing protocols these metrics are static and may not be changed. For other routing protocols these values may be assigned by a network administrator. The most common metric values are a hop, bandwidth, delay, reliability, load, and cost.

In my view, the two most major metrics used in routing protocols are hop and bandwidth.

Hop is a distance measuring metric which tracks the number of the network a particular datagram travels. A single hop signifies that a routing protocol has forwarded a datagram onto a segment. The assumption of the hop metric is that the path with the least number of hops is always the best route. One drawback of this metric is that protocols that do use this metric need not always select the most optimum data path. We must remember the fact that just because a path to a destination contains fewer network hops than another does not make it best

Bandwidth refers to the capacity of a network undertaking a datagram packet during a protocol. It is measured in terms of bits/second. These protocols determine and consider the bandwidth capacity of each link along the path end to end. The path with the overall higher bandwidth is chosen as the best route.