Networks Lesson 3 - Network Hardware

To connect a computer or device to a network, a number of hardware components are required:

a network interface controller

(NIC) or wireless network interface controller a transmission medium, either wired or wireless a point to connect to, such as a router, hub, switch or wireless access point

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

Most modern PCs come with a NIC and wireless NIC built in, providing the option of either connection method.

However, mobile devices such as tablets, smartphones and many embedded devices only feature a wireless NIC, giving only wireless connection.

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 differing characteristics.

Wired connections are reliable and not usually subject to interference. However, they limit mobility - a wired device usually has to stay in place.

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 as a device can connect to a network as long as it is in the range of a wireless access point.

A network connection device allows computers to connect to a network. There are four types of connection device to consider:

hubs switches wireless access points routers

• Hubs
• Switches
• Routers
• Wireless Access Points

Hubs have no knowledge of the devices connected.

Any signal (traffic) that arrives at the hub is transmitted to all connected computers.

This affects network performance as many unnecessary signals are transmitted across its connections.

Switches are similar to hubs, with one important difference - a switch records which computers are connected to which ports.

When traffic is received, the switch forwards the traffic to its intended recipient only.

This improves network performance by cutting down on unnecessary transmissions.

A hub broadcasts messages to all devices on the network. A switch sends the message to the intended recipient only.

A wireless access point uses a radio transceiver to allow wireless connections to a network.

In effect, the Wireless access point creates its own wireless network, which devices connect to.

It then sends wireless traffic it receives onto the main wired network.

They can also be used to extend the range of a wireless network. In this case the wireless access point can either receive and transmit traffic to other wireless access points or it can be connected via a cable to the main network.

Routers are one of the most commonly used connection devices. They are used to send data signals across the internet.

Routers work by collecting knowledge of available routes to transmit data. They then determine the most suitable route for sending data.

Routers are also commonly used in homes. These types of router usually contain a hub and a wireless access point, enabling a small peer-to-peer network to be formed. Additionally, they contain a modem, which allows users to connect to the internet.