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To connect a computer or device to a local area network (LAN), several hardware components are required:

• a network interface card (NIC) or wireless network interface controller (WNIC)
• a transmission medium, either wired or wireless
• a network connection device, such as a router, hub, switch, wireless access point (WAP), gateway or bridge

Network interface card

A network interface card (NIC) provides a method of connecting to a network. A NIC offers an interface port for a wired connection. A wireless network interface controller (WNIC) provides a radio transceiver for connecting wirelessly.

Most modern PCs come with a NIC and WNIC built in, providing the option of either connection method. However, mobile devices such as tablets, smartphones and many embedded devices feature only a WNIC, giving only wireless connection.

Transmission media

Transmission media carry data signals from one computer to another. Media are either wired or wireless.

In modern networks, wired media use either twisted copper wiring or fibre-optic cable. Each wired medium has particular characteristics:

Wired connections are reliable and not usually subject to interference. However, they limit mobility - a wired device usually has to stay in place. Most modern wired LANs use CAT6 cabling that allows connection speeds of up to 250 megahertz (MHz).

Wireless connections use radio waves to carry signals. These signals are limited in range (usually up to 50 metres) but are subject to magnetic interference. They can also be blocked by walls. However, they are ideal for mobile devices, which can connect to a network as long as they are in the range of a wireless access point (WAP).

Network connection devices

A network connection device allows computers to connect to a network and transmit data. There are several types of connection device to consider:

• hub
• switch
• wireless access point (WAP)
• router
• gateway
• bridge

Hubs

A hub is a small device that allows wired devices to connect to a network. Hubs have no knowledge of the devices connected. That means that all packets of data that arrive at the hub are transmitted to all connected computers. This affects network performance, as many unnecessary signals are transmitted across its connections.

Switches

Switches are similar to hubs, with one important difference - a switch records which computers are connected to which ports. When a message is received, the switch forwards each packet of data to its intended recipient only. This improves network performance by cutting down on unnecessary transmissions.

Wireless access points

A wireless access point (WAP) uses a radio transceiver to allow wireless connections to a network. In effect, the WAP creates its own wireless network which devices connect to. The WAP then sends the wireless traffic data it receives onto the main wired network.

WAPs can also be used to extend the range of a wireless network. In this case, the WAP can either receive and transmit traffic data to other WAPs or it can be connected via a cable to the main network.

Routers

Routers are one of the most commonly used connection devices. They are used to send data signals across the internet. Routers work by storing the addresses of computers on the network. They then determine the most suitable route for sending data.

Routers are also commonly used in homes. Home routers usually contain a hub and a WAP, enabling a small peer-to-peer network to be formed. They also contain a modem, which allows users to connect to the internet.

Gateways

A gateway joins together two networks that use different protocols, for example joining a LAN to a WAN.

Bridges

A bridge joins together two networks that use the same protocols, for example joining a LAN to another LAN.