Computer Networking:
To The Computer networks is the basis of communications in IT. So They are used in a many way’s and may including the many different type’s of the networks. A computer networks is a digital telecommunication’s networks that the allow node’s to share the resources. To The networks computing devices exchange The data with The each other using a data links. The Cable Of The media or wireless media are using for the connection’s between the node’s. A computer is made of a combinations of the network’s, hardware and the software’s.
What is Computer Network
The Computer networking is a groups of a computers and other devices for the purpose of The communications that are connected to the wired (LAN), wireless, or the Internet.
Network devices can have a variety of devices such as Server, switches , Printer, Scanner, and routers.To exchange information in the network, protocols and algorithms are used. Each endpoint of the network (sometimes called a host) is a unique identifier that is often an IP address or a Media Access Control (MAC) address. It is used to indicate the source or destination of a transmission. Endpoints may include servers, personal computers, phones, and many types of network hardware
Computer Network – Wired and Wireless Technology:Networks can use a mix of wired and wireless technology. Network devices communicate a wired or wireless transmission medium. In a wired network, optical fiber, coaxial cable or copper wires may be use .Data communication between all nodes in a wireless network is wireless. This medium can be broadcast radio, cellular radio, microwave and satellite.
Networks can be private or public. The user needs permission to access private networks. it is given manually by a network administrator or by a password or other credential to give the user access. There is no access restriction for public networks such as the Internet. A computer network is a communications channel through which we can share our data. Therefore it is also called data network.
Features of Computer Network – Criteria for Data Communications Network: Key Criteria that Data Communications Network Should Complete: Performance, Reliability, Recovery and Security
1) Performance: Performance is defined by the rate of error free data transferring. It is measured by response time. Response Time Computer Network- Where is the response time between sending the request from one end in the network and the response coming from the other end? Factors affecting Response Time are:
Number of users: If there are more users on a network then the network can be slow Transmission Speed: Data transmission speed is measured in bits per second (mbps) Media Type: physical connection used to connect nodes. Hardware Type: Fast like a slow computer or Pentium Software programs: How good are network operating systems (NOS).
2) Consistency: Consistency response time and data accuracy are predictive. Users always want the response time to be less, because if it is taking more than 30 seconds to deliver the print command and the print is coming, there may be some problem in the network.
3) Reliability: Network reliability is how often a network is usable. MTBF -Mean Time Between Failures (the time between failures) is a fraction of the average time in which a component works relatively between failures.it is given by the manufacturer. Failure of a network results from failure of hardware, medium or network operating system.
4) Recovery: Recovery is the network’s ability to return to a specified level of operation after a network failure.
5) Communication Speed The network provides us with the ability to communicate over the network in a fast and efficient way. For example, we can do video conferencing, email messaging etc. on Internet.computer networks are a great way to share our knowledge and ideas.
6) File Sharing File sharing is a major advantage of computer networks. Computer networks provide us with the ability to share files with each other.
7) Software and Hardware sharing We can install the application on the main server, you can centrally access the application.we don’t need to install software on every machine. same way hardware can also be shared.
8) Security: Security is protection from unauthorized use of hardware, software and data. Computers are provided with password protection for access.antivirus and firewalls are also used.
Components of a Computer Network – The major components of a computer network are as follows:
1) NIC (National interface card)
NIC is a device that helps a computer to communicate with another device. Network interface cards have hardware addresses, data-link layer protocols use this address to identify systems on the network so that it transfers data to the correct destination.
NICs are of two types: Wireless NIC and Wired NIC
a) Wireless NIC: All modern laptops use wireless NIC. a connection is made using an antenna that employs radio wave technology. b) Wired NIC: Wired NICs use cables to transfer data over the medium.
2) Hub
The Hub is a central device that divides network connections into multiple devices. When a computer requests information from a computer, it sends a request to the hub. The hub distributes this request to all interconnected computers.
3) Switches
Switch is a networking device that groups all the devices on the network to transfer data to another device. A Switch is better than a hub because it does not broadcast messages on the network, that is, it only sends the message to the device to which it belongs. Therefore, we can say that the switch sends the message directly from the source to the destination.
3) Cables and connectors
A cable is a transmission media that transmits communicated signals. There are three types of cables:
a) Twisted Pair Cable: It is a high-speed cable that transmits data of 1Gbps or more.
b) Coaxial Cable: The coaxial cable looks like a TV installation cable. Coaxial cable is more expensive than twisted pair cable, but it provides high data transmission speed.
c) Fiber Optic Cable: A fiber optic cable is a high-speed cable that transmits data using a light beam. It provides high data transmission speed as compared to other cables. It is more expensive than other cables.
4) Router
Router is a device that connects the LAN to the Internet. Router is mainly used to connect individual networks or to connect the Internet to multiple computers.
5) Modem
Modem connects the computer to the Internet over an existing telephone line. The modem computer does not integrate with the motherboard. A modem is a separate part on the PC slot found on the motherboard.
Computer Network Architecture
Computer network architecture is defined as the physical and logical design of software, hardware, protocols, and data, and the transmission media of data. Simply, we can say how computers are organized and how tasks are assigned to computers.
Two types of network architecture are used: Peer-To-Peer network & Client / Server network
1) Peer-To-Peer network
A peer-to-peer network is a network in which all computers are combined with equal privileges and responsibilities for the processing of data.peer-to-peer network is useful for small environments up to 8-10 computers. peer-to-peer network has no dedicated server.Each computer is given special permission to share resources, but this problem can occur if the computer with the resource goes down.
Advantages Of Peer-To-Peer Network
It is not much expensive because it does not have a dedicated server.
Even if one computer stops working, other computers will not stop working.
It is easy to set-up and maintain as each computer manages itself.
Disadvantages of Peer-To-Peer Network:
In the case of peer-to-peer networks, it does not include a centralized system. it cannot back up data because the data is different in different locations.
This is a security issue because the device itself is managed.
2) Client / Server Network
A client / server network is designed for end users called clients that can be accessed from a server, such as a central computer, known as a server.The central controller is known as a server while all other computers in the network are called clients. A server performs all major operations such as security and network management. A server is responsible for managing all the resources such as files, directories, printers etc.
All clients communicate with each other through the server. For example, if client 1 wants to send some data to client 2, it first sends a request for permission to the server. The server sends a response to client 1 to start its communication with client 2.
Advantages of Client / Server network:
The client /server network consists of a centralized system.we can easily backup data.
The client /server network consists of a dedicated server that improves the overall performance of the entire system.
Security is better in client /server networks as a single server administers shared resources.
It also increases the speed of shared resources.
Disadvantages of Client / Server Network:
The client / server network is expensive because it requires a server with large memory.
A server has a network operating system (NOS) to provide resources to clients, but NOS costs a lot.
This requires a dedicated network administrator to manage all the resources.
Use of Computer Network
1) Resource Sharing: sharing of resources such as programs, printers, and data between users on a network without need for resources and the user’s physical location.
2) Server-Client Model: Computer networking is used in the server/client model. A server is a central computer used to store information and maintain it by the system administrator. Clients are machines that are used to remotely use store information in a server.
3) Communication Medium: The computer network behaves as a communicating medium among users.example, a company has more than one computer that has an email system that employees use for daily communication.
4) E-commerce: Computer network is also important in businesses. We can do business on the Internet, which is called e-commerce. For example, amazon.com is doing their business on the Internet.
5) Retrieving Remote Information Through computer networks, users can get remote information on various topics. Information is stored in a remote database in which the user accesses through an information system such as the World Wide Web.
6) Highly Reliable Systems Computer networks allow systems to be distributed in nature, based on which data is stored across multiple sources. This makes the system highly reliable. If a failure occurs in one source, the system will still continue to function and data will still be available from other sources.
7) Cost – Effective Systems Computer networks have reduced the cost of installation of computer systems in organizations.before it was mandatory for organizations to install expensive mainframes for computation and storage. With the advent of the network, it is sufficient to set-up interconnected PCs for a single purpose.
Types of Internal Networks:
1) Extranet An extranet is a communicated network based on transmission control protocols and Internet protocols such as Internet protocols. It is used to share information. Extranet access is limited to only users who have login credentials. An extranet is the lowest level of internet working. It can be classified as a MAN, WAN or other computer network. An extranet cannot have only one LAN, at least it must have a connection to the external network.
2) Intranet An intranet is a private private based on Internet protocol such as Transmission Control Protocol and Internet Protocol. An intranet belongs to an organization which is accessible only by the employees & members of organization. The main objective of intranet is to share information and resources among the employees of the organization. An intranet facilitates working in groups and for teleconferences.
What is topology?
The topology defines the structure of the network by how all the components are interconnected. There are two types of topology they are 1) physical topology 2) logic topology.
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