Network Basics

A network is formed when two or more computers are connected together.

When computers are networked, it allows them to share data and resources. For example: data such as an email can be passed between different computers on a network, or a printer can be accessed by many by multiple computers without a direct connection.

There are many different types of networks, all of which serve different purposes.

The terms Local Area Network (LAN) and Wide Area Network WAN refer to the physical area a network covers.

Local Area Networks

A Local Area Network (LAN) covers a small geographical area such as a building. All the hardware that makes up the LAN is privately owned, e.g. the company using the LAN owns the LAN.

Examples of LANs include:

• Businesses
• Schools & Colleges
• Your own home

LANs can include wired and wireless devices.

Wide Area Networks

A Wide Area Network (WAN) connects LANs and computers over large geographical locations. WANs are owned by companies and access is rented or leased to its users (think about how people must pay for internet access).

Examples:

• The Internet - the largest WAN 
• VISA / MasterCard - payment providers which use their network to authorise digital payments
• Military - they use WANs to provide secure communication between their difference bases of operation.

WANs connect devices and LANs using ethernet, fibre, satellite and phonelines.

There are two models of how computers share resources on a network: Client-server and Peer-to-peer.

Most of the time this comes down to whether you want to use a server.

What is a Server?

A server is a computer which provides resources for other computers. Sometimes servers have to be very powerful and sometimes they may look no different from a regular desktop computer. Additionally, the server can occasionally provide more than one type of resource.

Client Server Networks

Client-server Networks are managed by servers.The server provides services to other computers on the network – this could be file management, access to printers, user access security. Schools use a client-server model: school servers store our files, manage us logging into computers, manage update and back-up and printing.

Benefits

• Central file storage: easier to back-up and access files from multiple computers.
• Managed security: password policy and  network rules.
• Reliable: servers are always on and resources/files will be available 24/7.

Drawbacks

• More expensive (requires expensive hardware).
• Requires experts to set-up and maintain.

Peer-to-Peer Networks

On a peer to peer network, all the computers are equal (no singular computer is more important than the rest). There is no server, so all computers share files and resources between themselves. Most home networks are Peer to Peer.

Benefits

• Inexpensive (doesn’t require expensive hardware or a server).
• Easy to set-up (doesn’t require expertise to set-up).

Drawbacks

• Slows down as more computers are added.
• Less reliable: resources and files can become unavailable if a computer fails)
• If computers are off their files and resources won’t be available on the network).