Introduction to Computer Networks

Before you start

Objectives: learn what is computer network, why do we use it and what do we need to create basic network.

Prerequisites: no prerequisites.

Key terms: network, connections, systems, media, communication, sharing, interface, usage, protocol, collaboration.


Systems

The first thing we need to have are the systems which we want to interconnect and have them communicate.

Systems

Image 133.1 – Systems

Media

The second thing we must have is some means of connecting all these nodes together. That’s done using connecting media. Media can be either piece of coaxial cable, fiber-optic cable, UTP cable or radio frequency. Different networks can use a variety of different connecting media.

Network Media

Image 133.2 – Network Media

Interfaces

The next thing we need to have is some type of network interface. We need to have something that connects the host system to the network media. Network interface takes digital data from the PC and converts them into some type of signal and then transmit the signals on the network medium. These signals can be electrical, optical or radio signals. Other network interfaces installed on other hosts that are also connected to the medium then receive those signals and translate them back into digital data.

Network Protocols

The next thing we need to have are network protocols. Protocol is an agreed-upon standard of how we are going to format information. Protocols are used so that devices located on the network can understand each other. It is similar to speaking the same language. If one host is configured to use one protocol and another host on the network is configured to use some other protocol, those two computers can not communicate because they don’t understand each other. Basically, the hosts have to “speak the same language”. Protocols are those languages.

Why do we use Computer Networks

The answer is that networks actually save organizations more money than they cost to implement. One example is using storage located on a remote system. Instead of users storing their company data on their local workstations, users can work with data located on the server over the network. This allows us to centrally manage, protect and backup important data. It also saves some money, because if we work with a lot of data, we don’t have to buy large hard disks for every workstation.

File Server

Image 133.3 – File Server

Networks also allow us to share network peripherals. The good example is sharing a printer. Without network, we would have to install a printer on every workstation. With network we can have one printer that is shared on the network and on which everybody can print on. This is an efficient use of resources. That one printer shared on a network will be used a lot, but that’s good. That means that it is being utilized most of the time, in contrast to the local printers which are most of the time just idle, using energy while waiting.

Network Printer

Image 133.4 – Network Printer

Another reason why companies implement networks is to increase communication, both internally in the company and externally with with the partners or customers. E-mail is a great way we can communicate inside or outside of our network. For example, instead of printing hundreds of memos with important announcement, with e-mail we can easily send that message to every person in our company. To communicate over network externally we can use e-mail or a company’s web page. Networks are also great for increasing collaboration. For example, multiple people can work on the same project files which are located on a shared storage. This way, whenever someone makes changes to the files, other team members can see those changes instantly.

Remember

Computer network is a group of computer systems that are interconnected so that they can share information with each other. To create computer network we need systems, media, network interfaces and protocols. Media can be either piece of coaxial cable, fiber-optic cable, UTP cable or radio frequency. Network interface takes digital data from the PC and converts them into some type of signal and then transmit the signals on the network media. Protocol is an agreed-upon standard of how we are going to format information. Computer networks are used because they actually save organizations more money than they cost to implement. Networks are also used to share network peripherals, to increase communication and collaboration.

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