Computer Notes Chapter- 15 Networking ! What is networking ! Need For Network ! Data Communication and Networks! Types of networks ! Local Area Network (LAN) ! Metropolitan Area Network (MAN) ! Wide Area Network (WAN) ! Components of Networks ! Hardward ! The Workstation and Server ! Server ! Workstation ! Network Interface Cards !
A group of computers that are connected together for the purpose of sharing various computer software and hardware resources like input-output devices, memory, storage like hard disk etc.
Need For Network :
Man is social animal. We cannot exit alone, without communication with different people around and moving from one place to another. Communication is one of the most important needs of our life Communication is a transport of not only words, text, but also involves people, sound, pictures and other kinds of relevant data.
As we come to the twentieth century, the technology seems to be changing towards information gathering, processing and distribution. Form simple talking, we have now reached a mode of sending letters through the computers, which is called Electronic Mail or E-mail Thus, technology is increasing the speed of communication and it is not costly .
All this is possible due to the computers being connected each other across the length and breadth of the world. So, for communication network is most important to connect computers to exchange information.
Communication technology has entered into this new phase because all the media are inter-connected. Some the popular modes of communication:
1. Talking
2. Letters
3. Telegrams
4. Fax machines
Data Communication and Networks:
Data communication has become possible mainly Because of computers. This technology involves transfer of information in the forms of object like text, pictures, sound etc. Computers are the devices that allow user to send and receive these objects. This leads us to a conclusion that there is a medium of communication between the sender computer and the receiver computers when there are more than one users computers, all the computers of the users are interlinked using communication wires to form a "Network ".
When the computers are interlinked the users of these machines can share data that is stored on the computers. Data is stored either in primary memory or secondary. A printer attached to one machine can be shared by the other, because of this connection. This means that there is data flowing through the connecting lines .
Types of networks:u
Computer network aim at data communication. Data can be in various forms like text, picture or sound. Data communication is required between two computers placed closely like in an office or placed at different location that cover a large geographic area.
The scope of a computer network may differ from small office premises to across that world. The geographic are covered by the computer network decides its type. Some of the different types of networks are.
Local Area Network ( LAN) :
A network that is limited to a relatively small spatial area such as a room, a single building, a ship, or an aircraft Local are networks are sometimes called a single location network.
Note: For administrative purpose, large LANs are generally divided into smaller logical segments called workgroup is a group of computers that share a computer set of resources within a LAN.
Metropolitan Area Network (MAN)
A network that connects two or more local Area Network of CANs together but not extend beyond the boundaries of the immediate town, city, or metropolitan area. multiple routers, switches & hubs are connected to create a MAN.
Wide Area Network (WAN) :
A WAN is data communication network that covers a relatively broad geographic area and that often user transmission facilities provided by common carriers, such as telephone companies,
Components of Networks :
The computer network is a system that has devices responsible for gathering data , processing it and finally distributing it. The system comprises of the hardware, software and the users.
In an organization local are networks are very commonly used. Many organizations have now connected single user PCs to other PCs from a local are network. Thus most PC users have now become members of a local are network. WANs and MANs line small LANs together. Hence local are networks in an important concept.
The components of LAN are also divided into hardware, software and the users.
Hardward :
Computer network is group of computers linked together to share data and resources. The hardware of the system is made up of various CPUs interlinked with communication lines.
The hardware required to from a network include :
1. The workstation and the server
2. Network Interface Cards
3. Hub
4. Cables
The Workstation and Server
Server:
A network stores data that can be used by may users of the system.The computer that is responsible to store all the the data and also to update information is called the server. this is where the data is processed its main function is to store all the files in the system that may either contain program or data it also makes these available to the users. Since it stores data in the forms of files, it is also called a file server.
The server loads may process in its memory it has to process and update information Hence, it has to be faster This is because data should be updated immediately and available to different users of the system. Hence the specifications of the server are more efficient as compared to the workstation to achieve faster processing and memory storage.
Workstation :
The computers that are responsible to accept the user inputs and transfer it to the server for processing are called workstation. workstation are also called as nodes or terminals of a network.
Thus a network forma a workstation server and workstation can access all the resources of the server these resources include the CPU memory input/output devices etc.
The minimum specification of a file server and workstation are tabulated below specifications of the network components change with respect to the setup Recommended figures are industry survey based for increasing the speed and efficiency of the network
Network Interface Cards :
The hardware of the computer system allows a single user to work on it. if many computers are connected together, the hardware should include a device that allows one computer to be connected to the other to concert a stand-alone computer as a member of the network, an additional electronic care is plugged into one of the slots in both the types of computer of the network i.e.the server and the workstation, the slot can be seen in the back of the machine this card forms a path also called a bus. (Connecting wires connects the internal parts of the CPU with the other device and themselves. these connecting wires are also called buses). The card is called a Network Interface Card (NIC). The card acts as an interface between the internal of the computer and the external connecting lines of the computer network.
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