Hop

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In networking, a hop is the link between two hosts a particular packet takes on its way across the network.

When sending a packet further than across the LAN, a packet must encounter a router or other device that operates at layer 3 (or higher). The path taken by a packet is comprised of a series of hops, and each packet can take a different path, based on decisions made by Internet routers.

Hops introduce significant latency to a network connection. Sending a packet through wires and switches is limited by the speed of light in the medium, and in practice, can be as fast as 50-70% of the speed of light. Each router in the path, however, must make a decision about where to send the packet, and depending on the routing protocol, the decision may take a lot of computation while the packet cools its heels.

The old routing protocol imaginatively named Routing Information Protocol used hop-count to determine the best way to direct packets.

You can use traceroute to trace the route of a typical network page.