Which metrics are used in a link-state algorithm (LSA) shortest path first (SPF) tree?

Link-state algorithms, like the Shortest Path First (SPF) algorithm, utilize specific metrics to calculate the most efficient routing paths through a network. The correct answer highlights the fundamental metrics used in these calculations: line speed, line delay, and hop counts.

Line speed refers to the data transmission rate of a link, which influences how quickly data can be sent over that link. Line delay is the amount of time it takes for a packet to traverse a link, which affects the overall responsiveness of the network. Hop count indicates the number of intermediate devices (routers or switches) a packet must pass through to reach its destination. This metric is critical in determining the efficiency of a path, as fewer hops generally indicate a more direct route.

In link-state protocols such as OSPF (Open Shortest Path First), the router builds a complete map of the network topology and uses these metrics to compute the shortest path tree for routing. The information about each link’s speed and delay contributes to making informed decisions about the optimal path for packet delivery. Using hop counts helps avoid overly complex but slower routes, promoting efficiency in data transmission.

The other choices include metrics that are either not applicable to link-state algorithms or are used in different contexts. Understanding these