When we wanted to make a long distance trunk call to someone a few decades ago, we had to go through a series of cumbersome steps to do so. Meanwhile, it would be extremely costly in terms of both time and money. However, as improved technology have been introduced, things have altered over time. With the help of cellphones, the internet, and computers, we can make a call, send a text, or send a video message in a fraction of a second by simply pressing a small button. Computer Networks are the primary driving force behind this cutting-edge technology. It’s a collection of nodes linked together via a media link. A node can be any device, such as a modem, printer, or computer, that can send and receive data generated by other nodes through the network.
Computer Networking: An Overview
A computer network is a digital telecommunications network that allows nodes to assign resources to one another. A computer network consists of two or more computers, printers, and nodes that transmit and receive data using wired media such as copper or fibre optic cable or wireless media such as WiFi. The Internet is the best example of a computer network. A computer network is not a system with a single control unit that is connected to other systems that act as slaves. Furthermore, it should be able to meet the following criteria:
Performance Reliability Security
Let’s take a closer look at these three. Performance: The transit time and response time, which are defined as follows, can be used to calculate network performance: Data transit time is the time it takes for data to travel from one source point to another. The time that has passed between the query and the response is known as response time. Reliability: Measurement of network failures is used to assess reliability. The lower the number of failures, the less reliable the system will be. Security: The way our data is safeguarded from unauthorised users is known as security. When data flows over a network, it passes through several layers. As a result, if data is traced, it can be disclosed by unauthorised users. As a result, the most important aspect of Computer Networks is data security. A good network is one that is highly secure, efficient, and simple to use, allowing users to readily share data on the same network without any security flaws.
Basic Communication Model
Components of Data Communication:
Message: It is the information to be delivered. Sender: The individual who sends the communication is known as the sender. Receiver: Receiver is the person to whom the message is being sent. Medium: It is the medium through which the message is sent. Consider the case of a modem. Protocol: This is a set of rules that regulate data transmission.
Computer Networks in Other Areas: It can handle all forms of data and messages, including voice, video, and text. It is extremely rapid, with data communication taking only a fraction of a second. It is a highly secure mode of communication that is low in cost and extremely efficient, as well as being simple to use.
Need for Computer Networking
The following are the various requirements:
Communication from one computer to another. Data exchange between different users on the same platform. Expensive software and databases are swapped. Information sharing over a wide area network. Printers, modems, hubs, and other hardware and software devices are shared via this protocol.
Uses of Computer Networks
Let’s look at some examples of computer networks in our daily lives and for business, and see how they will revolutionise these industries.
- Resource Sharing: The sole goal is to make all software and hardware equipment, particularly printers and switches, available to anybody on the network, independent of the sender’s or receiver’s physical location.
- Server-client Model: Consider a scenario in which a company’s data is held on a smart computer in the company’s office, which is well-protected by firewalls. Now, a firm employee must use his modest desktop to obtain data from afar. In this architecture, the employee’s PC serves as the Client, while the office computer serves as the Server.
- Communication Channel: In an office, a computer network provides a solid communication medium for the personnel. Almost any organisation with two or more computers will have an e-mail (electronic mail) system in place, which all employees will utilise for a large portion of their day-to-day communication.
- E-commerce: Nowadays, shopping online from the convenience of our own homes is fashionable. Doing business with customers through the internet is extremely convenient and time-saving. Customers prefer the convenience of purchasing from home, according to airlines, bookstores, online shopping, hotel booking, online trade, and music vendors.
Types of Network Topologies
The various types of Network Topologies are explained below with pictorial representation for your easy understanding.
BUS Topology:
In this topology, every network device is connected to a single cable and it transmits data only in one direction. Advantages:
Cost-effective Can be used in small networks. It is easy to understand. Very less cable is required when compared to the other topologies.
Disadvantages:
If the cable gets faulty then the whole network will fail. Slow in operation. Cable has a limited length.
RING Topology:
In this topology, each computer is connected to another computer in the form of a ring with the last computer connected to the first one. Each device will be surrounded by two other devices. The data flow in this topology is unidirectional, however it can be made bidirectional by utilising a dual ring topology, which uses two connections between each node. In a dual ring topology, two rings serve as the primary and protection links, respectively, such that if one link fails, data will flow through the other link, keeping the network operational. Advantages:
It’s simple to set up and expand. It is simple to utilise for transferring large amounts of traffic data.
Disadvantages:
The failure of a single node will have an impact on the entire network. In a ring topology, troubleshooting is challenging.
STAR Topology:
All of the nodes in this topology are connected to a single network device through a cable. The network device, which can be a hub, switch, or router, will serve as the central node, with all other nodes connected to it. With the central node, each node has its own dedicated connection. The central node can act as a repeater and is compatible with OFC, twisted wire cable, and other types of cable. Advantages:
Upgrading a Central node is a simple process. If one node fails, it will not effect the entire network, and the network will continue to function normally. It is simple to troubleshoot a problem. It’s easy to use.
Disadvantages:
The price is very high. Because all nodes are dependent on the central one, if the central node fails, the entire network will be disrupted. The core node’s performance and capacity determine the network’s overall performance.
MESH Topology:
With a point-to-point topology, each node is connected to the next, and each node is connected to each other. Data can be transmitted via the Mesh Topology using one of two methods. The first is routing, while the second is flooding. The nodes in the routing technique use a routing logic specific to the network to direct data from the source to the destination using the shortest path. Because the identical data is sent to all nodes in the network using the flooding technique, no routing logic is necessary. The network is resilient in the event of flooding, and data loss is rare; however, it adds undesired load to the network. Advantages:
It has a lot of strength. Faults are easily evident. Exceptionally safe
Disadvantages:
Extremely pricey. It’s difficult to set up and configure.
TREE Topology:
It has a root node, and all of the sub-nodes are connected to it in the form of a tree, forming a hierarchy. It usually has three layers of hierarchy and can be expanded to meet the network’s needs. Advantages:
It’s simple to spot a flaw. Depending on the needs, the network can be expanded at any time. Simple to keep up with.
Disadvantages:
The price is very high. It is tough to maintain when used for WAN.
Transmission Modes in Computer Networks
It refers to the way of sending data between two nodes connected by a network. Transmission modalities are divided into three categories, which are described below:
Simplex Mode:
Data can only be sent in one direction in this mode. As a result, communication is one-way only. We can simply transmit data here and not anticipate a response. Speakers, CPU, monitor, television broadcasting, and so forth are examples. Half-Duplex Mode: Data can be transmitted in both directions on a same carrier frequency in half-duplex mode, but not at the same time. For instance, in a walkie-talkie, the message can be conveyed in both ways, but only one at a time.
Full-Duplex Mode:
The term “full duplex” refers to the ability to send data in both directions at the same time. For example, a telephone allows both parties to talk and listen at the same time.
Transmission Mediums in Computer Networks
The transmission media is the medium through which data in the form of speech, message, or video will be sent between the source and destination points. The physical layer, which is the first layer of the OSI layer, is responsible for supplying the transmission means required to convey data from a sender to a receiver or to interchange data from one place to another. We’ll look at it more thoroughly in the future. We will determine which transmission medium is appropriate for data exchange based on parameters such as network type, cost & convenience of installation, environmental conditions, business needs, and distances between sender and receiver. Types of Transmission Media:
Coaxial Cable:
Coaxial cable consists of two wires that run parallel to one another. Copper is commonly used as a central conductor in coaxial cable, and it can be in the form of solid line wire. It is enclosed by a PVC installation with an exterior metallic wrapping on a shield. The outer component serves as a noise screen as well as a conductor that connects the circuit together. The outermost component is a plastic cover that protects the cable as a whole. It was used in analogue communication systems to convey 10K speech transmissions over a single cable network. Coaxial cable is also frequently used by cable TV network providers over their whole TV network.
Twisted Pair Cable:
It’s the most common wired communication medium, and it’s widely used. It is less expensive and easier to set up than coaxial wires. It is made up of two conductors (usually copper), each with its own plastic insulation and twisted together. One is used to transport signals from the sender to the receiver, while the other is grounded. Sending and receiving are done in separate pairs. Unshielded twisted pair and protected twisted pair cables are the two types of twisted pair cables. RJ 45 connector cable, which is a combination of four pairs of cables, is commonly used in telecommunication systems. It has a high bandwidth capacity and delivers high data and voice rate connections, making it ideal for LAN communication and telephone landline connections.
Fiber Optic Cable:
The core of a fibre optic cable is surrounded by a transparent cladding material with a lower index of reflection. Signals are sent between them using the characteristics of light. The process of total internal reflection, which causes the fibre to operate as a waveguide, keeps light in the core. Multiple propagation pathways exist in multi-mode fibre, and the fibres utilised to have larger core sizes. Intra-building solutions are the most common application for this sort of fibre. Single mode fibres have a single propagation path and a smaller core diameter than multimode fibres. Wide-area networks employ this type of fibre. A flexible and transparent fibre made of silica glass or plastic is known as an optic fibre. Coaxial and twisted pair cables, as well as electrical cables, transport signals in the form of light between the two ends of the fibre, allowing for transmission over greater distances and at a higher bandwidth. Because fibres are used instead of metal cables, the signal will travel with minimal signal loss from sender to receiver and will be immune to electromagnetic interference. As a result, its efficiency and dependability are quite high, and it is also extremely light in weight. Fiber optic cables are preferred over electric wires for long-distance communications because of the qualities listed above. The only disadvantage of OFC is its high installation cost, as well as its demanding maintenance.
Wireless Communication Media
So far, we’ve looked at wired communication modes in which we’ve utilised conductors or guided media for communication to transport signals from the source to the destination, and we’ve used glass or copper wire as a physical medium. Wireless communication media, also known as unguided transmission media, conveys electromagnetic signals without the use of any physical channel. The signals are transmitted over the air and can be received by anyone with the necessary equipment. Wireless communication uses frequencies ranging from 3KHz to 900THz. Wireless communication can be classified in three ways, as shown below:
Radio waves:
Radio waves are signals with a transmitting frequency ranging from 3 kHz to 1 GHz. These are omnidirectional because when an antenna transmits signals, it does so in all directions, which eliminates the requirement for sending and receiving antennas to be aligned. Any antenna with reception properties can receive radio wave signals if they are sent. Its problem is that because the signals are carried over radio waves, they can be intercepted by anyone. As a result, it is not suited for conveying classified or sensitive material, but it can be utilised in situations where there is only one sender and numerous receivers. It’s utilised in AM, FM, television, and paging, for example.
Microwaves:
Microwaves are signals that have a transmitting frequency ranging from 1GHz to 300GHz. These are unidirectional waves, which means that the sender and receiver antennas must be aligned when the signal is broadcast. Microwave communication has less interference problems than radio wave communication since the sender and receiver antennas are aligned at both ends. Microwave propagation is a line-of-sight form of communication, which means that towers with mounted antennas must be in direct line of sight. As a result, tower height is critical for proper communication. Microwave communication employs two types of antennas: the parabolic dish and the horn. Because of its unidirectional qualities, microwaves are useful in one-to-one communication systems. As a result, it’s quite common in satellite and wireless LAN communication. Microwaves can also be used for long-distance communication because they can carry thousands of voice data at the same time. Microwave communication can be divided into two categories:
Terrestrial microwave Satellite microwave
The microwave’s only drawback is that it is quite expensive.
Infrared waves:
Infrared waves are signals with a transmitting frequency ranging from 300GHz to 400THz. It can be utilised for short-range communication because infrared with high frequencies cannot penetrate rooms, preventing interference between devices. Neighbors using infrared remote control as an example.
Conclusion
We’ve looked at the fundamentals of computer networking and their importance in today’s digital world in this tutorial. The many types of media, topologies, and transmission modes that are utilised to connect the various sorts of nodes in the network are also discussed. We’ve also seen how computer networks are utilised for intra-building networking, inter-city networking, and the internet, or the World Wide Web.
