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TCP/IP Model of Computer Network

Here, we will learn about the TCP/IP model of a Computer Network in detail with its characteristics, layers, protocols, advantages, and disadvantages. 

What is the TCP/IP Model?

TCP/IP model is a Transmission Control Protocol/Internet Protocol model which is a concise version of the OSI (Open System Interconnection) model. 

This model was designed in 1960 by the Department of Defense (DoD). This model has a set of rules which helps in interconnecting the computers or network devices to the Internet. 
It also specifies how the data should be transferred over long distances. Unlike seven layers of the OSI model, this model only has 4 layers. 

Characteristics of TCP/IP Model

Following are the characteristics of the Transmission Control Protocol/Internet Protocol (TCP/IP) Model:
1. TCP/IP model is connection-oriented, i.e., the network devices should establish a connection before they transfer data to each other. 
2. Reliability is the most important characteristic of the TCP/IP model. 
3. This model ensures that the data reaches the destination in the same sequence it was sent. 
4. It allows you to implement the flow control, error checking, and recovery mechanism.
5. This model provides the full-duplex facility, i.e., the data can be transferred in both directions.

Layers of TCP/IP Model

The functionality of the TCP/IP model is divided into four tasks. And, each task is performed by the different layers. Each layer has a defined set of methods and protocols for performing that task.
The four different layers of the TCP/IP model are mentioned below:
1. Network Layer
2. Internet Layer
3. Transport Layer
4. Application Layer

Network Layer

Network Layer of TCP/IP model is the lowest layer and the combination of physical and data link layer of OSI reference model. Sometimes, this layer is also referred to as the host-to-network layer. 

This TCP/IP layer helps you to define how the data should be transferred physically using the network. It encapsulates the IP datagram into frames and maps the Internet Protocol (IP) addresses into the physical addresses. 
This layer does not define any protocol but supports all the standard protocols. 

Internet Layer

The Internet Layer of the TCP/IP model is the second layer and sends the data packets to the destination over the network. 
This layer routes each data packet from the sender to the receiver using the optimal route and handles the errors in the transmission. 
This layer uses the following three protocols:
1. IP protocol
2. ARP protocol
3. ICMP protocol

Transport Layer

The Transport Layer of the TCP/IP model is the third layer and provides the reliability, flow control, and correction of the data which is being sent by the source over the network. 

This layer of the TCP/IP model is similar to the transport layer of the OSI reference model. The main function of this layer is that it makes the delivery of data error-free. 
It also does functions like segmenting, multiplexing, and splitting of the data to be transferred over the network.  
This layer uses the following two protocols:
1. TCP (Transmission Control Protocol)
2. UDP (User Datagram Protocol)

Application Layer

The Application Layer of the TCP/IP model is the uppermost layer and allows you to interact with the application. 

This layer makes the node-to-node communication and controls the user-application interface. File transfer, e-mail services, and remote login are the best examples of the Application layer. 
This layer uses the following multiple protocols:
1. Simple Mail Transfer Protocol (SMTP)
2. Domain Name System (DNS)
3. File Transfer Protocol (FTP) 
4. TELNET
5. HyperText Transfer Protocol (HTTP)
6. Simple Network Management Protocol (SNMP)

Protocols of TCP/IP Model

Following are the most common TCP/IP protocols:
1. TCP
2. IP
3. HTTP
4. FTP
5. SMTP
6. SNMP
7. DNS

TCP

TCP is an abbreviation of Transmission Control Protocol. This protocol of the TCP/IP model divides the message into the small units called TCP segments and resembles all the segments based on the sequence number at the destination side. 
This protocol also ensures that the data is successfully transmitted from one device to another over the network. This protocol retransmits those frames which are damaged in the previous transmission.  
 

IP

IP is an abbreviation of Internet Protocol. This protocol of the TCP/IP model is the most essential protocol which decides the route for transmitting the data. 
It is also responsible for implementing the logical host address.  

HTTP

HTTP is an abbreviation of HyperText Transfer Protocol. This protocol of the TCP/IP model transfers the web pages and other web resources from the HTTP server to the HTTP client. 
It allows users to access the data over the World Wide Web and also transfers the plain text, audio, and videos over WWW. 

FTP

FTP is an abbreviation of File Transfer Protocol. This protocol of the TCP/IP model allows you to transfer the files from one device to another device over the network via the physical medium.
 
FTP also allows you to download the files to your computers from the other servers. It is mainly used for sharing files. 

SMTP

SMTP is an abbreviation of Simple Mail Transfer Protocol. This protocol of the TCP/IP model allows you to transfer the mail messages to other email addresses over the Internet. 

It exchanges the mail between the different email users on the same device or different device. You can easily send text messages, images, videos, audio, files, and graphics to one or more recipients.  

SNMP

SNMP is an abbreviation of Simple Network Management Protocol. This protocol of the TCP/IP model manages the network devices on the Internet. Sometimes, it also provides a set of methods to monitor the network and detects the faults that occurred on the network. 

DNS

DNS is an abbreviation of Domain Name System. This protocol of the TCP/IP model maps the names of the computers, devices, and services connected to the Internet. 
As we know, IP addresses are used to identify the connection of a computer or device to the Internet. But, some people use names instead of IP addresses. That's why DNS maps the names to the address.  

Advantages of TCP/IP Model

Following are the advantages or benefits of the Transmission Control Protocol/Internet Protocol (TCP/IP) model:
1. The main advantage of this model is that it is used to make a connection between the two different computers. 
2. This model supports multiple networking routing protocols. 
3. Scalability is a big advantage of this model because it allows networks to be added or removed without disrupting the current network service.  
4. This model uses control mechanisms such as flow control and error control. 
5. TCP/IP model is an open protocol suite. So, any user or any organization can easily use this model, because it does not belong to the particular institute or company. 
6. When this model is used on modem or LAN then it provides better performance. 
7. The last and final advantage is that it offers internetworking among different organizations. 

Disadvantages of TCP/IP Model

Following are the disadvantages or limitations of the Transmission Control Protocol/Internet Protocol (TCP/IP) model:
1. The TCP/IP model is complex. So, it is difficult to implement and manage.
2. In this TCP/IP model, the transport layer is not responsible for the delivery of packets. 
3. This model is not the best choice for LAN and PAN networks. It was only implemented for the WAN networks. 
4. The TCP/IP model does not replace the TCP/IP protocols easily.
5. This model is not suitable for describing the new technologies, because it has not clearly separated the concepts of interfaces, services, and protocols.  

OSI Model of Computer Network

Here, we will learn about the OSI model of Computer Network in detail with its characteristics, functions, advantages and disadvantages. 

What is the OSI Model?

OSI is an abbreviation of Open Systems Interconnection. It is a conceptual framework that describes how the data is transferred from the software application of one machine to the software application of another machine through the physical medium. 

This model uses the seven different layers for describing the network connections, so, sometimes this model is also known as the OSI seven-layer model. In 1984, the International Standard Organization introduced the OSI model for inter-computer communications.

In this model, the network architecture is divided into seven small different layers or sub-components. Each layer performs a specific task independently and interacts with the above and lower layer  automatically.

Characteristics of OSI Model

Following are the characteristics of the OSI Model:
1. This model helps to understand the relationship between the network devices easily over both small and wide area networks.  
2. This model helps the network administrators by dividing the large data chunks into smaller sub-components. 
3. As the data moves layer to layer, the function of each layer varies and the data complexity reduces. 
4. It also shows how the functions of software and hardware perform together.
5. The OSI model easily detects or finds errors at different layers.
6. The OSI model is categorized into the following two groups of OSI layers. 
a) Upper Layers:
Those layers which are closest to the end-user and deal with the issues related to the software applications.
b) Lower Layers: Those layers which are closest to the physical medium and which deal with the problems of data transmission. These OSI layers placed the data on the physical medium that needs to be transmitted. 

Function of OSI Model

OSI Model breaks down the network process into several layers. Each OSI layer performs a different function serially.  
Following are the seven OSI layers that play an important role in data communication:
1. Physical Layer
2. Data Link Layer
3. Network Layer
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer.

Let's discuss each layer in short one by one.

Physical Layer

The Physical Layer is the lowest and closest layer to the physical medium of the OSI model. This layer transmits the unstructured bits from one device to another over the network.

It establishes and maintains the physical connection between two or more network devices. It also specifies how the data is flowing between the two devices.

Data Link Layer

The Data Link Layer makes the data error-free which is transferred from one device to another. It divides the received data packets into frames and assigns the MAC address of sender and receiver to each data packet. 

Network Layer

The Network Layer finds the best path for sending the packet to the destination and places the IP addresses of sender and receiver in the frame header. 
This layer is responsible for breaking the segments into packets. It also resembles these packets received from the data link layer on the receiver device.  

Transport Layer

The Transport Layer receives the data from the higher layer and converts the data into segments. This layer makes the point-to-point connection between the sender and receiver device. 
It uses Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).  
This OSI layer controls the flow of data and performs the error control technique.

Session Layer

The Session Layer manages and synchronizes the interactions between the connected devices over the network. 
This layer also provides those services which include the functions of authentication and authorization. 

Presentation Layer

The Presentation Layer converts the data with the help of syntax and semantics for the application layer. Sometimes, it is also called the syntax layer. 
It uses encryption and decryption techniques for data security and privacy. 

This layer also performs the process of data compression. Data Compression minimizes the number of bits which are transmitted between the devices over the network. This mechanism transfers the bits at a fast speed over the network.

Application Layer

The Application Layer is the closest to the end-user and the uppermost layer of the OSI model. This layer directly interacts with the users and provides the network service to them with the help of software applications. 
HTTP and SMTP are the two protocols of the application layer.

Advantages of OSI Model

Following are the advantages of the OSI Model:
1. If the changes are done in one layer of the OSI model then those changes do not affect the other OSI layers.
2. It is a standard model and provides modular engineering in computer networking. 
3. This model supports both connectionless and connection-oriented services. 
4. Communication between the different types of software and hardware is easy.
5. As we know that, the model breaks the process into small subcomponents or segments. So, the design, development, and maintenance of the network are very easy in this model.
6. The security of this model is high.

Disadvantages of OSI Model

Following are the disadvantages of the OSI Model:
1. As we know, the layers do not work in parallel. So, each layer has to wait to take the data from its previous layer.
2. The initial implementation of this model is costly and time-consuming. 
3. Some services are common in more than one layer. Error Control and Flow control services are provided by multiple OSI layers.
4. The standards of this model are generic or theoretical. That's why practical implementation is not possible in this model.    

Computer Network Models

In this article, we will learn about  Computer Network Model and the layered architecture of the Network Model.

Computer Network Models define the architecture and design to establish the communication between the different network machines.
The models of computer network are also known as protocol suites, network protocols and network stacks. Network models efficiently transmit the data. 

A network model includes multiple layers. Each layer of the model performs the particular task and the collection of protocols and services are used in each layer to perform that task.  
Before we discuss the different models of computer network. Let's have to learn about the layered architecture of the network model.

Layered Architecture of Network Model 

The layered architecture of the network model divides the whole process of a network into small different tasks. And, each task is performed by a particular layer. 

In this Layered Architecture, all the layers are linked to each other and each layer receives the data from the previous layer and provides the data to the next layer. Services, Interface, and Protocols are the three basic elements of layered architecture. 
 
The network layered architecture consists of the following three main and major components:
1. Sender Machine
2. Physical Medium
3. Receiver Machine 

Sender Machine

In the network layered architecture, data is not sent directly to the receiver machine rather it passed from the higher layer to the lower layer via an interface present on the sender's machine.
The sender machine consists of the following layers:
1. Higher Layer: This layer accepts the data sent by the sender and passes that data to the middle layers for further processing.  

2. Middle Layer: Middle layer takes the data from the higher layer and uses its protocols and services and after that, it sends the data to the lower layer.

3. Lower Layer:  This layer picks up the data from the middle layer and sends the data to the lowest layer on the receiver machine by using the particular physical medium.
All these above layers are connected via an interface and perform their tasks one by one. 

Physical Medium

Physical medium specifies the way for transmitting the data from the lowest layer of the sender machine to the lowest layer of the receiver machine.

Receiver Machine

As we know that, data is not sent directly to the receiver machine rather it passed from the lower layer to the higher layer via an interface present on the receiver's machine.
The receiver machine also consists of the following three layers:
1. Lower Layer: This layer receives the data from the lowest layer of sender machine via the physical medium and transmits it to the middle layer after using its services and protocols.  

2. Middle Layer: This layer picks up the data sent by the lower layer and transfers it to the next higher layer after using its services and protocol. 

3. Higher Layer: This layer accepts the data sent by the middle layer and sends it to the receiver after using its services. 
All these above layers are connected via an interface and perform their tasks one by one. 

Two Computer Network Models 

Following are the two most predominant computer network models:
1.  OSI Model
2. TCP/IP Model     

Transmission Modes of Computer Network

Here, we will study the transmission modes of the computer network in detail with their advantages and disadvantages. 

Transmission Modes define the flow of data and information between the two network devices. Sometimes, we called transmission modes as data communication modes or directional modes. These modes are defined in the physical layer of the OSI model.

Firstly, data Communication modes were introduced in Modems during the 1940s. After then, these were introduced in LANs, WANs, and other networking systems.   

Following are three types of data transmission modes in a computer network which specify the data flow between the two network devices:
1. Simplex Transmission Mode
2. Half-Duplex Transmission Mode
3. Full-Duplex Transmission Mode

Simplex Mode

Simplex Mode is data transmission mode in which data flows only in one direction, i.e., the data communication between the devices is unidirectional. 
In a simplex data transmission mode, the sender device can only send the data and the receiver device only receives the data. The receiver device is not able to send the response back to the sender device.

Radio Station is the most common example of simplex mode, which transmits the signals to the listeners but does not allow them to respond back. 
Other good examples of simple mode are keyboard devices and monitor devices. The keyboard is a device which only takes the data from the outside world and the monitor is a device which shows the entered data to the user. The monitor is not able to give a response back to the keyboard. 

Advantages of Simplex Mode

Following are the advantages of Simplex Mode:
1. The main advantage of this mode is that it utilizes the whole bandwidth of the communication channel during the data communication. So, all data can be easily transferred at one time without any traffic issues. 
2. This data transmission mode is very simple. 

Disadvantages of Simplex Mode

In Simplex mode, bidirectional communication is not possible between the two network devices.

Half-Duplex Mode

Half-Duplex Mode is data transmission mode in which both the devices can transmit and receive the data but not in both directions at the same time. Sometimes, this transmission mode is also called Semi-Duplex mode. 
In this data transmission mode, when the sender sends the data then the receiver can only receive the data and vice-versa. Both the devices can not communicate with each other simultaneously. 
This transmission mode is used in those situations when there is no need for transmitting data for both directions at the same time. 

The most common examples of Half-Duplex transmission mode are walkie-talkie and Internet Browsers. In Walkie-talkie, speakers at both ends cannot speak at the same time. They speak one by one. 

Advantages of Half-Duplex Mode

Following are the advantages of Half-Duplex Mode:
1. The main advantage of this transmission mode is that the data can be transferred in both directions. 
2. It utilizes the whole bandwidth of the communication channel during the data communication in one direction at a time. 

Disadvantages of Half-Duplex Mode

Following are the disadvantages of Half-Duplex Mode:
1. The main disadvantage is that two-way communication is not possible between the sender and receiver at the same time. 
2. The speed of data transmission is slow. Because, when one device sends the data then another device has to wait until the whole data is received.

Full-Duplex Mode

Half-Duplex Mode is data transmission mode in which both the devices can transmit and receive the data in both directions at the same time. 
The communication between the sender and receiver device is bidirectional. This data transmission mode is used in those situations when there is a need for communication in both directions at the same time. 
The most common example of a full-duplex is the mobile phone, where two users can easily communicate with each other simultaneously. 

Advantages of Full-Duplex Mode

Following are the advantages of Full-Duplex Mode:
1. The main advantage of this transmission mode is that the data can be transferred in both directions at the same time.
2. Its performance is better than the half-duplex and simplex data transmission mode. 
3. The speed of transmitting the data in this mode is faster. 

Disadvantages of Full-Duplex Mode

This transmission mode uses the same transmission line for communication at the same time. So, it has no proper bandwidth utilization of the communication channel.

Computer Network Topologies

Here, we will learn about the topologies of the computer network in detail with their advantages and disadvantages. 

What is Topology?

The topology shows the geometric representation of the network of how the various computer devices and nodes are linked to each other.  

Following are the Six different types of Topology in the computer network:
  1. Bus Topology
  2. Ring Topology
  3. Star Topology
  4. Tree Topology
  5. Mesh Topology
  6. Hybrid Topology
Now, let's discuss all the above-mentioned topologies one by one in detail with advantages and disadvantages. 

Bus Topology

Bus Topology is a network topology which is constructed in such a way that all the devices share the same transmission cable. 
The common transmission cable in this topology is called Bus. A bus carries the data and information from one endpoint to another endpoint. 
Data sent by a computer or device moves only in one direction. When the data reaches the end then the terminator removes the data from the transmission cable. 
There is a dropline which connects each node or device to the transmission cable. 

In this topology, the transmission line acts as a spine, if it fails then all the devices connected to it stop their functioning or the complete network automatically breaks down. 

Advantages of Bus Topology

Following are the advantages of Bus Topology:
1. It is the simplest topology of a computer network for connecting the devices or nodes in a linear way. 
2. This topology is easy to set up and maintain. 
3. As compared to Star and Mesh network topologies, this topology requires less amount of cabling. So, its cost is less. 
4. It works well when the network is small, simple, and temporary. 
5. In this topology, we can easily connect and remove the node without affecting other nodes in a network.

Disadvantages of Bus Topology

Following are the disadvantages of Bus Topology:
1. The main disadvantage of this topology is that if the spine (transmission cable) fails then the whole system automatically breaks down or fails. 
2. Requirement of a terminator is necessary for both ends of the transmission cable. 
3. This topology is not the best solution for big and huge networks. 
4. If we add extra devices to the network then the performance of the network slows down. 
5. As compared to other network topologies its performance is very slow. 

Ring Topology

Ring Topology is a network topology which is constructed in such a way that each device is connected with two neighboring devices for data communication and sharing resources.
This topology is actually formed like a ring, i.e., the last device of the network is connected with the first device of the same network. Here, the data is transferred in a circular way.

In this topology, tokens are used to transmit the data from the sender node to the destination node. They hold the address of the destination node and pass the data from one node to each node until the destination device is reached.  

Advantages of Ring Topology

Following are the advantages of Ring Topology:
1. We can easily manage the ring topology and easily track the faults that occurred. 
2. As we know that the data is moved in a single direction, so the chances of packet collision is very low. 
3. As compared to other network topologies, the speed of data transferring is fast in this topology.  
4. This network topology is best for those applications which require low latency. 
5. We can add extra nodes to this topology without affecting its performance. 

Disadvantages of Ring Topology

Following are the disadvantages of Ring Topology:
1. The main disadvantage of this topology is that if one node fails or shutdowns then it affects the whole network.
2. As compared to the bus topology, the performance of this topology is slow. 
3. It is difficult to add or remove the node during the data transmission. If we do so, then it may affect the network. 
4. It is expensive because there is a requirement of hardware for connecting each device to the network. 

Star Topology

Star Topology is a network topology which is designed in such a way that all the devices/nodes are connected to the central device. 
In this topology, the central device acts as a server and the other connected devices/nodes act as the client. The name of the central device is hub or switch which uses a point-to-point connection. If the central device is a hub then it broadcasts the message and if the central device is switch then it unicasts the message. 

In this topology, if one device wants to send the data to another device, then the hub (central device) works as an intermediary device. Firstly, the hub receives the data sent from the sender device and after that passes the data to the destination device. 

Advantages of Star Topology

Following are the advantages of Star Topology:
1. The main advantages of star topology is that other devices not get affected if one device connected to the hub fails or shutdowns. So, its reliability is high.
2. This topology can be upgraded and reconfigured easily. 
3. It is best for large and huge networks.   
4. We can easily add and remove the device from the network without creating any disturbance to the network.

Disadvantages of Star Topology

Following are the disadvantages of Star Topology:
1. The main disadvantage of this topology is that if the hub or switch fails or shutdowns then the whole network automatically goes down. 
2. The cost of implementation is high because of the requirement of a hub or switch as the central device in this topology.

Tree Topology

Tree Topology is a network topology which is designed in such a way that all the devices/nodes are connected in a hierarchical structure.
It inherits the features of bus and star topology. Sometimes, it is also known as Star-bus topology.
In this topology, various star topologies are connected to the single bus. 

Advantages of Tree Topology

Following are the advantages of Tree Topology:
1. We can easily maintain the tree topology and track the faults.
2. Other devices of this network do not get affected if one device fails or shutdowns. So, its reliability is good.
3. If one hierarchy network fails or damaged then other hierarchy networks are not affected.  

Disadvantages of Tree Topology

Following are the disadvantages of Tree Topology:
1. As compared to the other network topologies, its configuration is hard. 
2. The performance of this network topology is a bit slow because of the presence of the huge number of nodes in the network. 
3. If we add a maximum number of nodes/devices to the network, then the network becomes complex. So, it is difficult to manage.

Mesh Topology

Mesh Topology is a network topology which is designed in such a way that all the devices/nodes are connected with each other via a point-to-point connection. 
Let's suppose, if there are N number of devices in this network topology, then each device is connected with (N-1) devices and the number of cables used would be (N(N-1)/2). 
Mesh Topology is categorized into two categories:
1. Full Mesh Topology
2. Partial Mesh Topology

Advantages of Mesh Topology

Following are the advantages of Mesh Topology:
1. Each node has multiple connections to reach the destination node, if one path is blocked then the other path can be used for transmitting data and sharing resources.  
2. There are no traffic issues in this network because a point-to-point connection is established between the two devices. 
3. We can easily detect the faults of this network topology. 
4. Communication is very fast in this topology because the devices/nodes are directly connected to each other. 

Disadvantages of Mesh Topology

Following are the disadvantages of Mesh Topology:
1. This topology requires a large number of cables and input/output ports. 
2. As we know that each device connected to all the devices. So, its setup is very complex and difficult. 
3. Due to the use of a large number of cables, it is quite expensive.

Hybrid Topology

Hybrid Topology is a network topology which is designed when two or more network topologies are connected with each other. 
The hybrid topology inherits the characteristics of mesh topology, bus topology, star topology, tree topology, and ring topology.  

Advantages of Hybrid Topology

Following are the advantages of Hybrid Topology:
1. This topology is very flexible because it can be constructed on the basis of organization requirements. 
2. Hybrid topology is reliable and scalable. It is scalable because the network size can be increased by adding the nodes or topology. 
3. This topology is used for designing extremely large networks.  
 

Disadvantages of Hybrid Topology

Following are the disadvantages of Hybrid Topology:
1. The main disadvantage of hybrid topology is that it is very difficult to implement.
2. As compared to other topologies, special hubs used in this topology for connecting the network are very expensive.  
3. The cost of its infrastructure is very high due to the large huge number of cables and network devices.  
4. If the central hub fails in this network topology, then the whole system automatically breaks down.
  

Types of Computer Network

Here, we will learn about the various types of Computer Network in detail with their definition, advantages and disadvantages.
Nowadays, there are 11 types of computer networks used for sharing data, applications and resources. But, some of these four popular computer networks are widely used. These four types of computer network are as follows: 
  1. PAN 
  2. LAN
  3. MAN
  4. WAN

Let's discuss the above four Computer Networks one by one. 

Personal Area Network (PAN)

Personal Area Network is a basic type of computer network which is established around one person in the range of 10 meters. 

This network helps to share the information within a range of 10 meters. It connects two computer devices, mobile devices, tablets, and Bluetooth enabled headphones.   
This type of network is deployed by using the Wi-Fi (Wireless Fidelity), Bluetooth, and USB (Universal Serial Bus) cable. 

Advantages of Personal Area Network (PAN)

Following are the advantages of Personal Area Network (PAN):
1. This network is highly secure and safe. 
2. Users can easily connect one device to two or more devices at the same time but within the range of 10 meters. 
3. You can use and manage this network easily. There is no advanced set-up required. 
4. If we use PAN in the range of 10 meters then its reliability and stability are excellent. 

Disadvantages of Personal Area Network (PAN)

Following are the disadvantages of Personal Area Network (PAN): 
1. The main disadvantage is that it does not allow sharing the information for long distances. 
2. In this network, the data transfer rate via Bluetooth and Infrared is slow as compared to a LAN network. 

Local Area Network (LAN)

Local Area Network is a group of computers and low-voltage devices which are connected in a small area such as home, laboratory, school, office, etc. 

The devices and computers in LAN are connected with coaxial cable, twisted pair cable, routers, and switches. 
Following are two most common technologies which are used in Local Area Network:
1. Ethernet
2. Wi-Fi (Wireless Fidelity)    

Advantages of Local Area Network (LAN)

Following are the advantages of Local Area Network (LAN):
1. This network is highly secure because there is no outside connection is connected with this network so the data which is shared in this network is highly secure.
2. Another big advantage of LAN is that it is cost-effective. Because, this network is built with cheap hardware like network adapters, hubs, and ethernet cables.
3. Due to its small size, the transfer rate of data is high as compared to other networks. 
 

Disadvantages of Local Area Network (LAN)

Following are the disadvantages of Local Area Network (LAN):
1. If the LAN administrator does not keep the server secure then the unauthorized user can steal the essential data of the organization. So, the privacy policies and set of rules should be correctly set up on the server. 
2. Another big disadvantage of LAN is that this network covers only a limited area. 
3. Initially, there is a requirement of the high cost to set up the LAN, because the costly special software is needed to make a system as a server.  

Metropolitan Area Network (MAN)

Metropolitan Area Network covers a town or entire city by interconnecting the different LANs to make a larger network of computers. 

In this type of network, LANs are connected with each other through telephone cables. In this network, computers are connected within the multiple banks in a city, multiple cities and towns, a single large city, or any large area with more than two buildings. 
Following are some protocols that are highly used in MAN are:
1. ATM,
2. ISDN,
3. ADSL
4. Frame Relay
5. OC-3, etc. 

Advantages of Metropolitan Area Network (MAN)

Following are the advantages of the Metropolitan Area Network (MAN):
1. As compared to the Local Area Network, the size and area of the Metropolitan Area Network are larger.
2. This network uses the fiber optical cable which helps to boost the speed of data transfer. 1000 Mb per second is the speed of MAN.  
3. Users can freely send local emails at a fast speed in this network.
4. As compared to the Wide Area Network (WAN), the size and area of the Metropolitan Area Network are smaller. And, it is highly secure. 

Disadvantages of Metropolitan Area Network (MAN)

Following are the disadvantages of the Metropolitan Area Network (MAN):
1. In this network, users need another cable for connecting two LANs. So, it is a problem of MAN. 
2. As compared to LAN, it is tough to make the system secure from hackers. In this network, data needs various high-security tools and highly trained administrators.  
3. Once the size of this network becomes large then it is difficult to manage and maintain.  

Wide Area Network (WAN)

A Wide Area Network is another computer network which covers a large geographical area such as the globe, country, or state. This network connects computers across longer distances. 

The biggest Wide Area Network in the world is the Internet. The Internet connects/joins all the computers together across the globe.   
In this network, telephone lines are used for wired communication and satellite links are used for wireless communication. 

Advantages of Wide Area Network (WAN)

Following are the advantages of Wide Area Network (WAN):
1. The main and big benefit of this network is that it covers the large geographical area for transferring the data over the network. So, the large organizations set up in different countries can easily communicate.   
2. Same as LAN, it also allows the sharing of applications, software, and infrastructure among distributed users.  
3. As compared to the Local Area Network and Metropolitan Area Network, it covers the larger geographical area.
4. Users can send messages across the globe with the help of applications such as Facebook, WhatsApp, zoom, skype, etc.

Disadvantages of Wide Area Network (WAN)

Following are the disadvantages of Wide Area Network (WAN):
1. WAN requires skilled and experienced network administrators to handle and manage.   
2. As we know that the area of this network is large and the use of technologies is more. That's why the security of this network is less as compared to the LAN and MAN.
3. The initial cost to set up this network is higher than the LAN and MAN. 

Other types of Computer Network

Apart from the above computer networks, following are some other types of Computer network:
  1. Wireless Local Area Network (WLAN or Wireless LAN)
  2. Virtual Private Network (VPN)
  3. Home Area Network (HAN)
  4. Storage Area Network (SAN)
  5. System Area Network ( also referred to as SAN)
  6. Campus Area Network (CAN)
  7. Enterprise Private Network (EPN)

Wireless Area Network (WLAN)

Wireless Area Network or Wireless LAN is similar to the LAN, but this network links the multiple different devices within a limited area via Wireless-Fidelity (Wi-Fi).

This type of computer network minimizes the use of physical cables. 
Users can make this network public or private according to the requirements. 
If all the devices are present in a limited area like a home, office building, or school, then all the devices can be connected using this network.

Virtual Private Network (VPN)

A Virtual Private Network is a private network which is established by using the public network for connecting the remote sites or users together.

This network is the best solution to protect the transmitted data from hackers or unauthorized users. It is established when we want to make a secure connection between the two locations.
The VPN systems use data encryption and high-security techniques to keep the data secure. 

Home Area Network (HAN)

Home Area Network is a computer network which is constructed by linking the two or more computers within the home.

This network is only beneficial for those homes having two or more computers. Users who are using this network can easily transfer the files and share the resources and programs of one computer to another.

Storage Area Network (SAN)

Storage Area Network  is an important high-speed computer network which links the storage device to more than one server. 

This network is mainly used for transmitting the data between multiple storage devices. This network makes the consolidated and block-level data storage devices. 
Converged, Unified, and Virtual SANs are the three different types of Storage Area Network. 

System Area Network (also referred to as SAN)

System Area Network is used for local networks when high processing is required. 
This network offers high bandwidth and low latency in the storage area network, server-to-server, and processor-to-processor environment. 

Campus Area Network (CAN)

Campus Area Network is a network which is larger than LANs but smaller than MANs and used for connecting the two LAN within the particular area. 
Sometimes, this network is also called Corporate Area Network, Controller Area Network, and Cluster Area Network. This type of network is mainly used in University Campus and small businesses. 

Enterprise Private Network (EPN)

Enterprise Private Network owned by those businesses which want to connect all the computers of  the various locations for transmitting the data and sharing the resources.  
This network allows communication between the computer devices and shares the resources within an enterprise via cables, wireless media, and other technologies.  
 

What is the Full Form of Computer?

Here, we will learn about the COMPUTER and its full form. So, let's start to read to understand it. 
A 'Computer' is an electronic machine which is used widely all over the world. Almost everyone uses the computer for performing the operations and functions quickly and correctly. 
But, only some of the peoples in the world know the full form of computer. A computer is a complete word in itself. So, it has no full form. But, some peoples say that:

The Full form of Computer is "Commonly Operated Machine Particularly Used in Technical and Educational Research". 

What is Computer?

COMPUTER is a word that comes from the word 'COMPUTE'. The word Compute means calculate or count.
It is an electronic machine which helps humans to make fast logical and arithmetic operations using various hardware and software. Computer systems use computer programming or coding for performing calculations and operations.  
Computers accept the raw data given by the user and process that data and then produced meaningful results to the user in milliseconds and microseconds.

Block Diagram of Computer

The block diagram of the Computer consists following three parts or components:
1. Input Unit
2. CPU
3. Output Unit

Input Unit

It is the first component of the computer system which allow the users to enter the raw data and information into the computer from the outside world with the help of input devices such as scanner, mouse, keyboard, joystick, etc. 
 
The input unit also converts the entered data into the computer's understandable language. 

Central Processing Unit (CPU)

It is the main and second component of the computer system. This component is also known as the brain of a computer system. 

This hardware device performs all the logical and arithmetic operations on the data and controls all the units and data flow of the computer. This device also stores the data and information on a temporary or permanent basis. 

Output Unit

It is the last and third component of the computer system which provides meaningful results to the user after processing.

The output unit converts the result into human understandable form and then supplies it to the outside world with the help of output devices such as a monitor, printer, etc. 

Types of Computer

Following are the five main types of Computer:
1. Super Computer 
2. Mainframe Computer
3. Mini Computer
4. Workstation
5. Personal or Micro Computer. 

Advantages or Benefits of Computer

Following are some advantages of Computer in real life:
1. Computers can easily store and access a huge amount of information. 
2. It helps humans to complete their complex tasks in few seconds. It also completes those tasks which are impossible for humans.
3. Computers give 100% accurate results if the user entered the correct inputs. 
4. We can easily store millions of songs, movies, and videos in our computer systems. And, We can entertain ourselves by watching the videos and listening songs.
5. By connecting the computers to the internet, you can easily earn money and pay the various bills from home. 
6. Today, computers are widely used in government and private offices, schools, hospitals, etc. 

Disadvantages or Limitations of Computer

Following are some disadvantages of Computer:
1. Due to computers, unemployment is increasing day by day, because they perform various tasks automatically which reduces the need for peoples. 
2. Playing games on computers and chatting with friends affects education. 
3. Nowadays, computers are used in every field, so the chances of cybercrime are more. Bank account hacking and computer hacking are the two most common real-life cyber crimes. 
4. Children and adults use computers for a long time which can cause a headache. 

Other full forms of 'COMPUTER'

Following are some other full forms of the word 'COMPUTER':
  • "Common Operations Made Possible Under Technical Engineering Researches".
  • "Common Operating Machine Particularly Used for Training, Education, and Reporting". 
  • "Computing Oriented Manipulation Programming Used in Technology Education and Research".

Name of Top Computer Brands 

Following are the names of top computer brands in the World:
1. Apple 
2. Dell
3. Hewlett Packard (HP)
4. Lenovo
5. Asus
6. Acer