Computer Network Basics

       

In computer science there are different areas of subjects as networking, web development , development and so many other fields. Apart from them in this article I am fond of giving you all a very basic introduction to computer networks.

Apart from trying the coding parts first let me  look something on the theory part , that mean the basic understanding on computer networks . Here I would like to give such introduction to a beginner in computer network.

Mainly networking is done to achieve some communication aspect or to perform some communication activity in order to perform some duty. So it is good to have a quick look at data communication approach.

In the start you may really feel that this is boring and something like reading a lecture note. But as a beginner you need to know these basic things and I am trying to give those basic ideas as short as possible but as more detailed to set it clear to you about basics of data communication and networks .

Basic Requirements for a successful data communication:

            1. Communication medium

            2. Two or more parties

            3. Use of protocols

Here the use of word protocol is very important in computer networking. In future articles on computer networking   I will let you know what a protocol is and how it I important. Here my main aim is to provide you all with basic and a very root approach to computer network stuffs .

Data Communication Components:

1. Sender and Receiver.

2. Medium.

3. Data and Protocols.

These are the components involve in data communication to be happened . 

Delivery , accuracy and timeliness are the characteristics of data communication system.

Delivery mean the data should reach the relevant destination properly . Accuracy mean that data should be same as they were send. No modifications should be happen. Timeliness mean data should reach the destination at correct time because late data are useless .

In data communication data passes and communicate as signals. What are these signals? How they are made ? 

Signals can be generated by changing the strength of certain form of energy with respected to time in a certain medium.

Form of energy  : Electrical or light may be

Medium : copper , optic fiber or free space.

Mainly these all type of signals can be divided in to main two parts .

1.     Analog signals

2.     Digital signals

(Basics : so not going to explain them)

You can get a simple understand by looking at the structures.

And in signal science there is a important word as frequency spectrum and it is really important as well. It is collection of all frequency components.

Data transmission rates can be measured by two ways

1.     Bit rate – No bits per second

2.     Baud rate-No of symbols per second

NB: In signal analysis there are some simple  calculations regarding some equations and I am not going to do and explain them here in this article.

Signal conversion , encoding techniques and simple calculation parts with equations will be done in another separate article by providing much overview.

Here in next few topics I would like to give some more basics of transmission.

Communication modes:

1                    1.simplex :  Data transmission only allowed to one direction .

          Eg  : [Tv and Radio]

      2. Half – Duplex: Data transmission allowed to both sides but not at same   time.               Eg:[Walkey-tokey]

      3. Duplex  : Two way communication allowed. 

          Eg: [phone]

                               

Transmission Modes :

     1.Serial Transmission :

        Data transmits over one channel one bit at a time.

     2. Parrel Transmission :

        Data transmits over multiple channels multiple bits at  time.

Concepts of switching and service protocols also really important and useful in getting a clear idea on data communication because these technical words mainly  use in the industry of computer networking.

SWITCHING : Two Types

1. Packet switching : Data to be sent are first divided in to packets or message blocks before transmitting and rejoin to form the original message when reach the destination.

2. Curcuit switching : In circuit switching there is a separate dedicated channel for entire communication.

Service protocols :Two types

1.Connection oriented : Logical connection between two parties must be there to start the communication. Mainly TCP coming under this.

2.Connectionless : There are no any logical connection should be there to start the communication. UTP coming under this.

You may wondering what TCP and UTP are ? In future articles about computer network. For now just assume them as protocols used in computer networks.

In data communication activities as well as in network activities the concept of multiplexing plays a very important roll. Multiplexing mean set of techniques that allows transmission of multiple signals across a single data link .

     

Here it mainly uses a multiplexer and a demultiplexer . In the multiplexer it consists of modulators and demultiplexer consists of filters.

There are three types of multiplexing as FDM TDM and WDM.

To provide you all a quick review on multiplexing I would like to give a brief introduction on FDM . FDM standards for Frequency Division Multiplexing.

It is done using a multiplexer. Here inside the multiplexer it has modulators. They modulate those coming bandwidths into high frequency ranges and avoid overlapping of separate signals . Then they are shifted and combine to one signal inside the multiplexer. Then de-multiplexer involve in the process will filter and demodulate those signals to form the original ones. Following figure can be use to get a clear idea on what FDM does in multiplexing.

                 

                               

To give you basic introduction about computer networks I would like to tell something about basic networking devices in computer networks. These basic devices are used to perform network operations and data communication activities in a much more aggressive and a efficient way. 

This little basic introduction may help to understand and get a brief and a sketch idea on what these devices are and what them capable of performing.

• Repeaters are use simply to enlarge simple networks. Mainly used in smaller LANs. Allow different media types to connect as segments.

• Bridges are used to connect two LANs to make larger ones. They can filter traffic passing between two LANs. Can use to connect segments based on different architectures.

• Routers are used to forward packets from one network to another. It mainly relies on a routing table. Figure out best route use in making the delivery.

• Hub and Switch are also multiple port bridges that render different services as Hub forwards a received frame out of all interfaces or devices and switch forward a received frame only to the required interface. Switch is really intelligent.

Next it is about LAN

LAN standard for Local Area Network . In this small introduction to LAN I would like to give basic idea about what a LAN is and how it perform it duties well .

LAN shares resources such as files , hardware and it is limited in size . This sharing of resources will be done under fixed assignment , contention based and token based ways.

Lower In cost compare to WAN .

Require very little wiring and can be made wireless as well.

NOS – Network Operating System is the software that enables user to share files and hardware and which allow you to communicate with other computers. 

                         

Next it is about Network Typologies.

The word topology is important and might be new to you . Structure of communications that links between hosts on a  network is simply a topology .

There are so many topologies and I will not going to give them in detailed but just a quick picture will display all stuffs as follows.

                

They are structures how computers are placed in a network . An overview.

        I thought this article might give you  basic stuffs in a much simple and appropriate way for you to as a beginner.