What is Networking? 

Networking refers to the communication shared between a group of computers. A group of computers connected to each other for the purpose of sharing resources and information is called a computer network. The first computer network was ARPANET, which stands for Advanced Research Projects Agency Network.

Characteristics of a Computer Network

Characteristics of a computer network include:

• Resource sharing
• Communication
• Backup
• Scalability
• Reliability
• Software and hardware sharing
• Security

Network Infrastructure Devices

Network devices are used to connect a computer to a wider area network. There are many types of network devices that make up networking infrastructure.

Hubs

A hub is a network device that is used to connect multiple computers in a network. Hubs broadcast messages, which means only one device can communicate at a time. This makes them less expensive than switches, which allow sending and receiving at the same time (see below). Hubs are easy to install and robust due to their simple nature. 

Switches

Similarly, a switch is a network device that connects multiple computers together in a network. It is used to send unicast messages and provides more security and stability than a hub. Unlike hubs, switches support full duplex data transmission, meaning multiple devices can communicate at the same time. Switches are more expensive than hubs and can require some advance setup, depending on the environment. But they offer more security and faster communication speeds than hubs.

Routers

A router is a network device that works as a traffic controller to connect separate networks. A router's main job is to choose a congestion-free path, using a routing algorithm, through which the data packet will travel. The transmission rate is very high. Routers are more expensive compared to other network devices and can be complex to maintain. 

Repeaters

A repeater is a network device through which we can boost a weak signal by regenerating the weak signal. It is cheaper than other network devices. Repeaters have the ability to extend the length of signal by increasing or maintaining the signal performance. Multiple repeaters may be needed after a certain distance because repeaters are unable to connect dissimilar types of networks. They cannot reduce network traffic.  

Bridges

A bridge is a network device that is used to separate LANs (Local Area Networks) into sections. By using a bridge device, we can extend the network. Bridges broadcast data to each node within the network, such as the hub and repeater. Bridges do not establish a connection between two different networks. Once a bridge has broadcast a message, it is incapable of stopping the message. The transmission rate of data is slower than a repeater. 

Gateways

A gateway is a hardware device that is used to connect two dissimilar types of networks with different protocols. It operates all seven layers of protocols. We cannot access the internet without a gateway. It provides some security. Data transmission rate is slower. Gateways are difficult to maintain as well as very complex. 

Types of Networks

• PAN: A Personal Area Network (PAN) is used at home for personal use. The range of this network is less than 10 meters.

• LAN: A Local Area Network (LAN) is most commonly used in office and building areas. The range of this network is less than 150 meters. 

• MAN: MAN stands for Metropolitan Area Network. These networks are used within a city, with a range of this less than 50 kilometers.  

• WAN: WAN stands for Wide Area Network and is used for connecting countries or all around the world. The range of this type of network is not fixed. 

Network Topology 

The physical arrangement of the computer systems or nodes which are connected to each other via the network is called topology. Various important types of topology are discussed below.  

• Bus Topology: In bus topology, one long cable acts as a single communication channel and all the devices are connected to this cable. It is easy to add and remove nodes in a network with bus topology, as its only requirement is a cable. This also makes it fairly inexpensive. It broadcasts messages to each device connected through the cable and is easy to maintain. In case of any computer failure, there will be no effect on other devices, but if the cable fails then the entire network will fail. Messages are broadcast through this topology so we cannot send private messages. Another downside is it takes more time to transmit the messages, and the length of cable is limited. Also, in this topology data is transmitted only in one direction. 

• Ring Topology: As the name suggests, this type of topology forms a ring. In this topology, each node is strongly connected with its adjacent node, forming a strong network. The transmission rate of data is very fast, but it is very difficult task to add new network devices, and we cannot send private messages. 

• Star Topology: In a star topology, all the nodes are connected with a central hub, which broadcasts messages. This is fairly inexpensive because it requires less cable, though it does require a network device like a hub and router. We cannot send private messages. 

• Mesh Topology: In a mesh topology, every computer is directly connected with each other. This is a very good topology to send private messages because it provides point-to-point connection. Here, some difficulties arise when adding a new node. If a particular machine is not working, then we cannot send or receive data from the failing machine. 

• Hybrid Topology: A combination of various different topologies is called a hybrid topology, 

• Tree Topology: In this topology, all the nodes are connected like the branches of a tree. Bus and star topologies are forms of tree topology. 

Advantages of Networking 

• File sharing is possible. 
• Network security is ensured via protocols. 
•  In an N/W, there is no hassle in adding new devices.  
• A backup and storage facility is available in the network. 

Disadvantages of Networking 

There are also some notable disadvantages of networking systems, as listed below.  

• Virus attacks are very much possible if security is compromised.
• A handler is always required.
• A high-speed internet connection is necessary. 
• Server connectivity is mandatory.

Context and Applications 

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for:

• Bachelors in Computer Science   
• M.S in Computer Science