Fundamentals of Communications and Networking, 3rd Edition

Switching Concepts

The main difference between devices to connect networks is how much work they must do to decide where to send each packet. Higher-level devices, such as routers and gateways, operate at the OSI Network Layer or higher. The higher a device operates within the protocol stack, the more processing power and intelligence the device itself needs. Software is what powers a bridge, router, brouter, switch, or gateway; however, the more powerful and intelligent the device, the more costly it becomes. It requires more processing power to examine each Ethernet frame or IP packet and then to determine the best path to take. When a packet requires many hops to get from its source to destination, the added work can cause noticeable performance ...