Network Hardware Components (Layers 1 and 2)

This chapter focuses on network media and the physical layer—layer 1 of the Open Systems Interconnect (OSI) model. It also presents various layer 1 and layer 2 devices including connectors, transceivers and media converters, repeaters, network interface cards and PC cards, bridges, and switches. Connectors attach components together. Several types of connectors are available, serving various purposes: (1) to connect network interface cards such as an Ethernet card to a cable, (2) connect cable segments, and (3) terminate a segment. In this last category, connectors actually connect the cable to a terminating resistor or an array of resistors and are consequently known as terminators. The type of connector used is usually a function of cable type. Media converters enable different network media to be connected to one another. These operate at the physical layer and provide a simple mechanism for extending the distance between two devices by mixing copper and fiber cable.