Basic Concept on Computer Network
Network
A network is a system where everyone can share information or work together. For example, suppose the postal department delivers letters across the country. For this the postal department has a nationwide network. They have different offices in different places in this network, there are some rules and regulations. Here every part of the network is working. If the postal department does not have such work then they cannot work. Such networks can be used in the case of computers. Network consists of different devices, which are connected by different communication links. Devices can be computers, printers etc. A computer is part of a network when it is connected to one or more other computers to share information. A minimum of two computers is required to network. Apart from that, the rules of how one computer will communicate with another computer, what their language will be, etc. are specified in advance.
Computer network
A computer network is a group of interconnected (Inter-connected) computers and related devices, which can easily exchange information and share resources among themselves. All the hardware resources that are used in a large amount in the network are printers, faxes, modems, scanners and storage devices such as hard disk, CD or compact disk, plotter etc. On the other hand, stand-alone (Stand alone) or a single computer means a computer that is not connected to a network. To share data, graphics or documents processed on a stand-alone computer with others, it must be printed on a printer or copied to disk. In the case of networking, these information or document sharing tasks are done by the computer itself. The network operator or user does not have to move this information at their own risk.
Advantage of computer network
The middle of computer network is computer or PC. Needless to say, the progress that information technology has made in recent years is largely due to the contribution of computers. Currently there is no alternative to computers in data storage and transport. Information is processed by coordinating appropriate software with the computer. And the free flow of this processed information and its availability to users increases the productivity of any organization manifold.
A computer provides the following benefits to an organization:
(a) Word Processing,
(b) Graphics Design,
(c) simulation,
(d) Accounting,
(e) Numerical Analysis,
(g) Inventory tracking etc.
(f) database,
Simply put, a computer network is formed by connecting two computers with the help of a cable. Networking allows computers to exchange data with each other very efficiently and quickly. The concept of sharing resources through computer culture is called networking. The following image shows such a simple network.
Just as the process of coordinating two or more objects through something is called networking, the process of coordinating two or more computers through Cable, Modem or Satellite is called computer networking. Computer networking allows multiple users to work on a single computer at the same time as a single user can use multiple computers at the same time. Communication, exchange of information using computer networks, internet quorum, electronic mail, electronic library, bulletin board etc. are increasing in prevalence and spread.
There are three main parts of a computer network. Part three is-
(a) Sender (b) Modem and (c) Receiver.
Application of computer network
Currently, the practical field of computer networks is quite wide. Day by day its use and functionality is expanding. Some of the areas of use of computer network are given below:
(a) Exchange of information: Exchange or sharing of all types of information in business organizations may not be secure. However, networks are used to refer to organizations that place the following information on a central server and share it for use by clients in a controlled manner.
(i) Inventory
(ii) Company letterhead or letter style (Company letter style)
(iii) Sales Contact Information
(iv) Procedural manual
(v) Financial record
(vi) Employee record
(vii) Company memos
(b) Hardware Resource Sharing: Let's say there are 10 computers and one printer in an office. The computers and the Christ are not networked. A single printer is connected directly to a computer. In such a situation, the rest of the computers that are not connected to the printer should either bring a pen drive to the computer connected to the printer to print a document or remove the printer and connect it to that computer. will be Both of these processes are quite cumbersome for printing documents.
The only solution to the above problem is to bring the computers and printers under a local area network. If it is connected to the network, it is possible to send printouts to that one printer easily from any computer. That is, the printer is a shared hardware resource in this case. Such more shareable hardware resources are available. Among them are scanners, plotters, hard disks and modems.
(c) Software Resource Sharing: When software is installed and configured centrally in an organization's network, that software or program becomes a usable resource for other clients of the entire organization. This process greatly reduces the software installation and maintenance workload for the network administrator.
(d) Data Storage: Networking enables all clients to store or backup all data on a central reliable storage media or server. Storing data on a central reliable storage media greatly reduces the chance of sudden loss of important data. Backing up data from a stand-alone or network-isolated computer is a difficult task. But regularly backing up data to a central disk on the network is largely simple and hassle-free.
(e) Data security: In network based computing, each user or user is assigned a unique name and password. If the user wants to use the resources of that network, he must use this assigned name and password correctly. As a result, anyone authorized to use the network cannot gain access to stored data at will.
(f) Exchange of messages or messages: Exchange of information or documents or messages on paper from one place to another within the office is time-consuming on the one hand and costly on the other. Networked clients can easily exchange documents and instant messages with each other in the form of electronic mail or e-mail. This process brings speed to office work and at the same time guarantees 100% security of documents or messages.
Client-Server Network
Usually when we receive any data, the computer from which we receive the data or service is called server. We are clients or consumers because we serve from it. In this network, both workstation and server computers have the opportunity to work autonomously with their own CPU and memory. It consists of a graphical user interface or front end program on the client workstation and other facilities. It stores the back end server programs of one or more servers.
In other words, a suitable network for centrally storing data, ensuring security, running various applications and running the network is a client-server network. In this network, one computer owns the resource, and other computers in the network use those resources. The computer that shares the resource is the server, and the computers that share the resource are the clients. All the resources of the network are stored on the server so the resources can be managed from the center. Security is ensured as all users log into the same server and adhere to the server's security policy.
Characteristics of client-server network:
A client-server network is also called a server-based network. Characteristics of client-server network:
(i) Client-server network is easily expandable. This can be done for anything from ten users to thousands of users.
(ii). Such networks consist of servers. Server computer hardware is usually of high quality and these servers provide various services to other computers.
(iii) Client-server network is very secure as it uses user level access control.
(iv) Such networks can be centrally controlled by network administrators.
(v) Users in such networks do not require network management. That is why the skill of the network users is not so important.
Difference between Client Server and Peer to Peer Network:
Peer to peer network
(i) All computers connected to a network are of the same class or peers and are called peers.
(ii) Computers in this network play the role of both server and client, so no separate server addition is required.
(iii) Ease of design and maintenance of peer to peer networks.
(iv) Cost is lower in peer to peer network.
(v) In peer to peer network security of information cannot be maintained as information is not stored in a central server.
Client Server Network
(i) The central computer used in it is called server and the computers connected to the server are called workstations or clients.
(ii) It requires the addition of one or more servers to the network, whose back-end programs respond to a client.
(iii) Design and maintenance of client server network is relatively complex.
(iv) Cost is relatively high in client server network.
(v) It stores information on central servers and ensures security of information from authorized users.
Hybrid network
A mixed or hybrid network is essentially a combination of client-server and peer-to-peer networks. Generally, the client-server portion dominates in a hybrid network. However, in addition, there are sparsely coupled peer-to-peer network segments. Advantages of hybrid network are:
(i) Client-server applications can be centrally hosted and managed.
(ii) Users can control access to their respective computer resources and share their resources.
Disadvantages of hybrid network are-
(i) Having two types of networks makes it difficult for users to access the network.
(ii) Need to remember different passwords for workgroups and servers/domains.
(iii) Due to the presence of resources on different computers, they cannot be managed centrally. Different versions of the same file can be scattered across different computers.
(iv) Difficulty backing up files stored on different workstations.
Network architecture
Designing and implementing an effective network with respect to communication rules and interconnection design is called network architecture. Network architecture deals with information encoding and its transfer, error control, flow control, customer address identification, analysis of network performance under abnormal conditions, etc. Most networks are organized in a series of layers or hierarchical structures to avoid complexity in network design. In this case each layer is placed on top of the previous layer. The number of network layers, the names, capacities or functions of each may vary. However, in all networks, the job of each layer is to provide services to the layer above it. A number of layered protocols are used to establish successful communication between entities at different levels of the network. All communications of the nth level entity of the sending station Conventions adopted for data exchange are called nth layer protocols. The set of network layers and protocols discussed above is collectively called the network architecture.
List of Network Operating Systems:
The system software used for managing all the resources under the network, security provision of the network, user or user management is called network operating system. Some of the operating systems used in networking servers are --
(i) Novel Netware
(ii) Windows NT, Windows Server, Windows 2000 Server etc.
(ii) UNIX
(iv) Linux Fedura, Ubuntu, Red Hat Linux, Susi, Sent OS etc.
(v) Samba
(vi) Banyan Network System
(vii) Apple Share IP
(viii) SUN Solaries
(ix) IBM OS/2
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