What is a computer network?
There are different types of networks that provide us with different types of services. For example, during the day a person can make a call, watch a TV show, listen to the radio, search for something on the Internet, or even make a game with someone in another state. All these activities that are done in everyday life depend entirely on different networks. Networks provide the ability to connect people and devices wherever they are in the world. People use networks without ever thinking about how they work or how it might be if networks did not exist.
Some of the main usable networks today are:
Computer / data networks, which are networks that provide communications between computer users through copper wire, fiber optic and wireless connections.
Telephone networks connect callers and enable modem connectivity, using traditional landline and wireless landlines, such as cellular telephony.
Television networks provide regular, high quality wireless, cable and satellite broadcasting.
Communication technology in the 1990s and earlier required separate networks for voice, video and computer data. Each of these networks required a different kind of device to access these networks. Telephones, televisions and computers used specific technology and dedicated network structure to communicate. But what happens if people want to access all these network services mentioned above at the same time, maybe using a single device?
New technologies create a new kind of network that provides more than one kind of service. Unlike dedicated networks, these new converged networks are able to provide voice, video, and data services over the same communication channel or network structure.
New products that are on the market today utilize all the opportunities offered by these converged information networks. Now people can watch live video streams on their computers, make a phone call via the Internet or search the Internet using the TV. Converged networks make this very good.
The benefits of networking
Networks are of different sizes. They range from simple networks consisting of two computers, to networks that connect millions of devices. Networks installed in small office or home office are known as SOHO (Small Office Home Office) networks. SOHO networks enable the sharing of resources, such as printers, documents, photos and music, between some locally connected computers.
In business, large networks can be used to advertise and sell products, order equipment and communicate with customers. Network communication is usually more efficient and cheaper than traditional forms of communication, such as ordinary mail or calls outside the district and state. Networks allow fast communication, such as email and instant messaging, and provide storage and retrieval of information from various network servers.
Business and SOHO networks typically have an Internet connection. The Internet is considered a "network of networks" because it actually consists of thousands of networks that are related to one another.
Some other uses of a network and the Internet are:
Exchange music and video files
- Distance learning and distance education
- Real-time chat with friends
- Vacation Planning
- Purchase of gifts and equipment, etc.
There are also many uses of networks, without which today's work is hampered.
Small household networks are networks that connect some computers to each other and generally have a common Internet connection.
SOHO networks enable connecting computers to another company network to communicate and share resources.
Medium-to-large networks, such as those used by large companies or schools, may have several points that contain hundreds of thousands of computers connected to each other.
World-wide networks, such as the Internet, are networking networks that connect hundreds of millions of computers worldwide.
Basic networking components
There are many component parts that can be part of a network, such as personal computers, servers, network devices, and cabling. These constituent parts can be grouped into four main categories:
- Computers
- Common peripherals
- Network devices
- Networking environment
Components of networks that people are more familiar with are computers and peripheral devices. Computers are devices that send and receive messages directly to the network. Common peripherals are not connected directly to the network, but are connected to computers. The computer is responsible for making the peripherals available on the network, such as a printer. Computers have computer software configured to enable people on the network to use peripheral devices connected to them.
Network devices, as well as the broadcast environment, are used to interconnect computers with each other.
Some devices can play more than one role, depending on the connection. For example, a printer connected directly to a computer (local printer) is a peripheral device. A printer connected directly to a network device and communicating directly to the network is called a network end device.
Network roles in the network
All computers connected to the network that communicate over the network are plugged into the network end-band set. Computers and network devices can send and receive network messages. In modern networks, computers can behave as a client, server, or both at the same time. The software installed on the computer determines the role that the computer plays.
Servers are computers that have installed software that enables them to provide information, such as e-mail or web site, to other computers on the network. Each service requires special server software. For example, a computer requires web software to provide web services on the network.
Clients are computers that have installed software, enabling them to search and display the information received from the server. An example of client software is a web browser such as Internet Explorer or Mozilla Firefox.
Client and web server: The web server executes server software and clients use their browsing software, such as Internet Explorer or Mozilla Firefox, to open web pages stored on the server.
Client and file server: The file server retains the file, the client device accesses the file with client software such as Windows Explorer.
Client and Email Server: The email server executes server software and clients use e-mail client software, such as Microsoft Outlook, to access e-mail on the server.
A server software computer can provide simultaneous services to one or more clients.
In addition, a single computer can execute multiple types of server software. At home or in small businesses it may be necessary for a computer to serve as a file server, a web server, and an e-mail server.
A single computer can also execute multiple client software types. There must be client software for each service that is required. With many clients installed, a computer can connect to multiple servers at the same time. For example, a user can control e-mail and view a web page when at the same time doing "chat" and listening to the Internet radio.
Peer-to-peer networks (one-to-one)
Client and server software is usually executed on separate computers, but it is also possible for a computer to perform both roles at the same time. In small businesses and at home, many computers function as servers and clients on the network. This kind of network is called one-to-one network. The most simple one-to-one network consists of two computers connected directly, using a cable or wireless connection.
Similarly, many computers can connect to create a larger one-to-one network, but this requires a network device, such as a hub, to interconnect computers.
The main shortcoming of a one-to-one environment is that the performance of a computer can slow down if it works both as a client and as a server at the same time.
In larger businesses, due to the possibility of large amounts of traffic, it is often necessary to have dedicated servers to respond to the number of service requests.
The advantages of a one-to-one network are:
- Easy to configure
- Not complex
- Lower cost, as long as no network equipment and dedicated servers are required
- Can be used for simple tasks such as file transfer and printer sharing
One-to-one network disadvantages are:
- There is no centralized administration
- Not very sure
- Not extensible
- All devices work both as a client and as a server, which can lower their network performance
Networking topologies
In a simple network made up of several computers, it's easy to see how all the network components are connected. As networks expand, it is more difficult to track the location of each department and how each constituent part connects to the network. The cable network requires many cables and network devices to provide connectivity to all its end devices.
When networks are installed, a physical physics map is created to mark where each computer is located and how it connects to the network. Physical topology map also shows where cables and network devices are connected to connect the end devices to each other. In order to present the actual physical devices, icons are used within the topology map. Maintaining and updating maps and physical topology is very important as it helps to install and locate problems later when changes are made.
In addition to the physical topology mapping, it is sometimes necessary to have a logical view of network topology. A logical topology map groups computers and end devices out of the way they use the network, no matter where they are physically located. Computer names, addresses, group information, and applications can be stored in a logical topology map.
The graph below illustrates the difference between logical and physical topology maps.
Source, channel and destination
The primary purpose of each network is to provide a method for exchanging information. From the earliest people to the most advanced scientists today, exchanging information with others has been and remains important for human development. All communication begins with a message or information that needs to be sent by an individual or device to another. The methods used for sending, receiving, and interpreting messages vary by time with the advancement of technology.
All communication methods have three common elements. The first of these elements is the source of the message or the sender. The message sources are people or electronic devices that need to communicate a message to individuals or other devices. The second communication element is the destination or recipient of the message. The destination takes the message and interprets it. A third element, called the communication channel, provides the way in which the message travels from source to destination.
Rules of communication
In every conversation between two people, there are many rules and protocols that both must follow, so that the message goes well and properly understood. Among the protocols for successful human communication are:
- Identification of sender and recipient
- Broadcast environment or accepted communication channel (face-to-face, phone, paper, photo)
- Proper communication mode (spoken, written, illustrated, interactive or one-way)
- Common language
- Grammar and sentence structure
- Speed and pace of delivery
Imagine what would happen if there were no protocols or rules to determine how people communicate with each other. Would you be able to understand them? Are you able to read the paragraph that does not follow commonly agreed protocols?
The same rules and communication protocols are absolutely necessary to apply to terminal equipment communications in computer networks.
