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Text D: Local Area Networks

Today, most LANs are configured with Ethernet technology and use compatible Wi-Fi standards in applications that require wireless access. When you connect your computer to a home, school, or workplace network, it will probably use Ethernet or Wi-Fi standards, so these technologies are worth a more detailed look.

In 1980, Bob Metcalfe’s 1976 concept for Ethernet became commercially available. Ethernet simultaneously broadcasts data packets to all network devices. A packet is accepted only by the device to which it is addressed.

The original Ethernet standard carried data over a coaxial cable bus topology at 10 Mbps. Today, the term ‘Ethernet’ refers to a family of LAN technologies that offer various data transmission rates over fiber-optic and twisted-pair cables arranged in a bus or star topology. Fast Ethernet is currently the most popular for small to medium LANs, like those you might find in homes and small businesses.

Workstation and other devices that connect to an Ethernet require Ethernet circuitry, which can be built into the main board or added as an Ethernet card.

These cables link workstations and peripherals to a central connection point called an Ethernet hub. Today, most Ethernet hubs also serve as routers.

Wi-F, the Ethernet’s cousin, refers to a set of wireless networking technologies defined by IEEE 802.11 standards that are compatible with Ethernet.

As with a wired Ethernet network, every workstation and network peripheral requires network interface circuitry, which can be built in or added as Wi-Fi card. A Wi-Fi card includes a transmitter, receiver, and antenna to transmit signals. Wi-Fi cards for notebook or tablet computers can plug into a PCMCIA slot or USB port.

Bluetooth is a short-range wireless network technology that’s designed to make its own connections between electronic devices, without wires, cables or any direct action from a user. Unlike Wi-Fi, Bluetooth is not typically used to connect a collection of workstations. Instead, Bluetooth connectivity replace the short cables that would otherwise tether a mouse, keyboard, or printer to a computer.

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