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2. Computer Networks


 

What is a computer network?

 

To put it very simply, a computer network is a group of computers linked together. They share and exchange information and perform tasks to achieve business objectives - all directed by the users.

 

Within a typical computer network you will find the following components:

  •   A Server that holds the information and data (pictures, files, databases and email)
  •   Individual computer systems (desktops and laptops)
  •   Network Switches and Network cables that link all the computer systems together
  •   A Modem/Router that will allow the network to communicate via the internet with the outside world
  •   A Firewall that protects the business data from unauthorized access by outsiders
  • Most business also add a wireless access box allowing the information to be accessed by portable devices (like laptops etc)
  • All of the above links devises such as printers, faxes, scanners and other networkable machines

In more technical terms, the computers are able to communicate and exchange information because they use software that observes the same set of 'parameters', or protocol. In a small/medium business environment it's common to see a server present as the central place of communication which holds all of that information and allows the business to create a hierarchy of data access depending on each user or staff member's role in the business. A good way to describe the role of the server is to describe it was the brain of the system, whilst the computers are the arms and legs that get the network moving. All networks operate using the same basic principle: Whenever a computer in a network sends information to another computer or peripheral, the information is in the form of what's called a "packet." When the packet reaches the designated station, the information is transferred to the computer.

Why do computer networks exist and what role do they play?

The interconnection (or networking) of multiple computer systems within an office is known as a Local Area Network (LAN). It's used to allow and process the communication and exchange of information within the office. For example, the sharing of documents, accounts, databases access to emails and internet is achieved by utilizing computer networks.

The role of the computer server is usually to create a central point where information is shared, different permission levels are granted and backups can be performed at a single place. This server-type office network environment is the most common and is usually recommended by IT experts.

What are the different types of networks and what are they used for?

There are 3 renowned types of computer networks that you may or may not have have heard of; and they are LAN, WAN and VPN.

LAN (Local Area Networks)

Local Area Networks are commonly utilised by small to medium businesses to interconnect all of their systems together, share information, communicate internally amongst staff and users and allow for centralized storage and management of information. In order to achieve this type of system, usually a server is required that involves Windows, Linux or other operating systems. It is safe to say that Windows and Linux are the most popular operating systems amongst businesses.

WANs (Wide Area Networks)

Wide Area Networks move beyond the confines of a workplace and are usually used to connect with other offices or branches within a business. WANs basically work on their ability to connect Multiple LANs together. A WAN is essentially a long distance network: it can connect systems together throughout a country, or even to outside the country and overseas locations.  

VPNs (Virtual Private Networks)

Virtual Private Networks are used to interconnect individual users to an Office by providing a secure, encrypted link or whats called a 'tunnel'. This is especially handy for workers on the go or at an off-site location who may need access to a workplace database or network. Additionally, VPNs can be used to interconnect separate workplaces using a public connection (Internet) in a very secure manner so that the exchange of information between offices is kept private.

Network Hardware Requirements

The basic equipment that you will need to set up a network besides your server and computer system/s includes:

  • Network cards
  • Cables
  • Networking software
  • A "hub" into which all the cables are connected.

Network Interface Card (NIC)

One of the most critical pieces of hardware when creating a network is what's known as an adapter. The adaptor allows the computer to "talk" to the network, and is also known amongst IT professionals as a network interface card (NIC). Network interface cards differ from each other primarily in terms of connection speed. NICs today generally support at least 100Mbps (Gigabit), and most now have the capability of 1000Mbps (Gigabit) connections (this is widely recommended).

Some computers do come with the NIC and the necessary accompanying software drivers that are needed pre-installed. If your computer/s do not have cards already built in, you'll need to organise a separate purchase and installation. NICs range in price from just $15 to more than $150. Whichever NIC you do decide to choose, you should try to settle on the same brand for all your computers for easier troubleshooting in the future.

Switch

All networks require the presence of a switch. The switch essentially acts as a central traffic cop for the network, managing the receiving and transmitting of data from networked devices. Each computer and peripheral that you want to add onto your network must have a cable that runs from the Network Interface Card that is installed inside it to the switch.

Switches do vary in price, depending on the connection speed that they are able to support and how many devices they can connect. Each connection is known as a "port." Switches come in many different port configurations and capabilities. Prices for switches that support a smaller number of ports can start for as low as $100. However Switches can reach much higher prices that stretch into the hundreds, even thousands, for supporting multiple or many users.

Cables

Finally, it's essential that you have cables to connect each computer to the switch. The primary types of cables that are used include twisted pair and fiber optic cables. These days, the most popular type of wiring used in most offices is known as a Category 5e (Cat 5e) cable. This particular type of twisted pair cable can support network speeds up to 1000 Mbps (1 Gb).

Ethernet

Ethernet has over time become the standard of networking technology from small to large businesses everywhere, being the most widely implemented standard. The different types of Ethernet are distinguished or designated in terms of the data transfer speed each supports.

So what type would you need? Well, it depends largely on the size of your business and the requirements of your network.

  • 100Mbps (mega bits per second) is the minimum for business network connections.
  • 1000 Mbps is usually opted for by b usinesses with a large number of connected PCs, large amounts of data to transfer and share, or more room in their budget.
  • 10ge Gigabit (10 Gbps) Ethernet networks are also available, but are only suitable for much larger companies with multiple networks and hundreds of employees. (This technology is quite cutting edge and is now supported by most vendors)

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