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LEARNING OUTCOME 1

COMPUTER NETWORKING

Computer networking is the process of connecting two or more computing devices to exchange data and share resources.

EXPLAIN COMPUTER NETWORKS IN LINE WITH ORGANISATIONAL NEEDS

Data communications is the transfer of data between two or more devices. This can be done over a variety of media, such as copper cables, optical fibers, or even the air.

Computer networks are a collection of devices that are interconnected so that they can share data and resources. Computer networks can be small, such as a home network, or large, such as the Internet.

ADVANTAGES OF USING COMPUTER NETWORKS

1. Resource sharing: Computer networks allow users to share resources, such as printers, scanners, and software. This can save businesses money and improve efficiency.
2. Improved communication: Computer networks allow users to communicate with each other more easily and quickly. This can be done through email, instant messaging, video conferencing, and other applications.
3. Increased productivity: Computer networks can help businesses to improve productivity by allowing employees to access information and resources more easily. They can also help to streamline workflow and collaboration.
4. Enhanced decision-making: Computer networks can help businesses to make better decisions by providing access to real-time data and information. This can help businesses to identify trends, spot problems, and make better-informed decisions.
5. Global reach: Computer networks allow businesses to reach a global audience. This can help businesses to expand their markets and grow their businesses.
6. Cost-effectiveness: Computer networks can be a cost-effective way for businesses to communicate, collaborate, and share resources.
7. Scalability: Computer networks can be scaled up or down to meet the needs of businesses. This makes them a flexible and adaptable solution for businesses of all sizes.
8. Security: Computer networks can be made secure by using encryption and other security measures. This can help to protect businesses from data breaches and other security threats.
9. Ease of use: Computer networks are relatively easy to use. This makes them a good option for businesses that do not have a lot of technical expertise.
10. Innovation: Computer networks can help businesses to innovate by providing access to new technologies and applications. This can help businesses to stay ahead of the competition.

DISADVANTAGES OF USING COMPUTER NETWORKS

1. Security risks: Computer networks are vulnerable to security risks, such as hacking, malware, and data breaches. This can lead to the loss of sensitive data and financial losses.
2. Dependence on technology: Computer networks are dependent on technology. This means that if the network fails, businesses can lose access to important information and resources.
3. Complexity: Computer networks can be complex to manage and maintain. This can require businesses to invest in training and resources.
4. Cost: Computer networks can be expensive to set up and maintain. This can be a barrier for businesses with limited budgets.
5. Downtime: Computer networks can experience downtime. This can disrupt business operations and lead to lost productivity.
6. Privacy concerns: Computer networks can raise privacy concerns. This is because data that is transmitted over the network can be intercepted by unauthorized individuals.
7. Bandwidth limitations: Computer networks have bandwidth limitations. This means that the amount of data that can be transferred over the network is limited. This can impact the performance of applications and services that rely on the network.
8. Technical support: Computer networks require technical support. This can be a challenge for businesses that do not have the in-house expertise to manage and maintain the network.
9. Compliance requirements: Computer networks must comply with a variety of regulations, such as data protection laws. This can be a challenge for businesses that need to ensure that their networks are compliant.
10. Obsolescence: Computer networks can become obsolete. This means that businesses may need to upgrade their networks to keep up with the latest technologies.

ANALOG SIGNALS

Analog signals are used to transmit data over physical media such as copper wires and coaxial cables. Analog signals are continuous in time and amplitude, meaning that the signal can take on any value within a certain range. They are typically transmitted using a technique called modulation.

Modulation is the process of combining an analog signal with a high-frequency carrier signal. The carrier signal is a pure sine wave that is used to transport the analog signal over the physical medium. Once the analog signal has been modulated, it can be transmitted over the physical medium to the receiving device. The receiving device demodulates the signal to recover the original analog signal.

Analog signals are used in a number of different computer networking applications, including:

• Telephone networks: Analog signals are used to transmit voice traffic over telephone lines.
• Cable TV networks: Analog signals are used to transmit video and audio signals to cable TV subscribers.
• DSL networks: Digital subscriber line (DSL) networks use analog signals to transmit high-speed data over telephone lines.
• Wireless networks: Analog signals are used in some wireless networks, such as AM radio and analog cellular networks.

Analog signals are also used in a number of different computer networking components, such as:

• Modems: Modems convert digital signals from computers into analog signals that can be transmitted over telephone lines or other physical media.
• Network adapters: Network adapters are used to connect computers to networks. Many network adapters support both analog and digital signaling.
• Routers and switches: Routers and switches are used to route and forward data packets between different networks. Some routers and switches support both analog and digital signaling.

ADVANTAGES AND DISADVANTAGES OF ANALOG SIGNALS IN COMPUTER NETWORKING

Analog signals have a number of advantages over digital signals in computer networking, including:

• Simplicity: Analog circuits are often simpler to design and implement than digital circuits. This can make analog networking equipment less expensive to manufacture.
• Compatibility: Analog networking equipment is often more compatible with older networking equipment than digital networking equipment.
• Noise tolerance: Analog signals are more tolerant of noise than digital signals. This is because analog signals can be filtered to remove noise.

However, analog signals also have a number of disadvantages over digital signals in computer networking, including:

• Bandwidth: Analog signals require more bandwidth to transmit than digital signals. This is because analog signals must be sampled at a high rate to accurately represent the original signal.
• Susceptibility to distortion: Analog signals are more susceptible to distortion than digital signals. Distortion can occur when analog signals are transmitted over long distances or through noisy environments.
• Error rate: Analog signals have a higher error rate than digital signals. This is because analog signals are more susceptible to noise and distortion.

DIGITAL SIGNALS

Digital signals are signals that represent data as a sequence of discrete values. At any given time, a digital signal can only take on one of a finite number of values. This contrasts with analog signals, which can represent any value within a continuous range of values.

Digital signals are used in a wide variety of applications, including:

• Communications: Digital signals are used to transmit data over computer networks, telephone lines, and wireless networks.
• Computers: Digital signals are used to represent data and instructions inside computers.
• Storage: Digital signals are used to store data on digital media such as hard drives, optical discs, and flash memory.
• Consumer electronics: Digital signals are used in a wide variety of consumer electronics devices, such as TVs, DVD players, and MP3 players.

ADVANTAGES AND DISADVANTAGES OF DIGITAL SIGNALS

Digital signals have a number of advantages over analog signals, including:

• Noise immunity: Digital signals are more immune to noise than analog signals. This is because digital signals can be easily regenerated and amplified without introducing distortion.
• Error detection and correction: Digital signals can be easily detected and corrected for errors. This is because digital signals are represented as a sequence of discrete values, which can be checked for errors.
• Efficiency: Digital signals can be transmitted more efficiently than analog signals. This is because digital signals can be compressed to reduce their bandwidth requirements.

However, digital signals also have some disadvantages, including:

• Complexity: Digital circuits are more complex to design and implement than analog circuits. This can make digital equipment more expensive to manufacture.
• Bandwidth requirements: Digital signals require more bandwidth to transmit than analog signals. This is because digital signals must be sampled at a high rate to accurately represent the original signal.

DIGITAL SIGNALS IN COMPUTER NETWORKING

Digital signals are used in a wide variety of computer networking applications, including:

• Ethernet: Ethernet is a widely used networking technology that uses digital signals to transmit data over copper wires or fiber optic cables.
• Wi-Fi: Wi-Fi is a wireless networking technology that uses digital signals to transmit data over radio waves.
• DSL: Digital subscriber line (DSL) is a technology that uses digital signals to transmit high-speed data over telephone lines.
• Cable modems: Cable modems use digital signals to transmit high-speed data over cable TV lines.

Digital signals are also used in a number of different computer networking components, such as:

• Network adapters: Network adapters are used to connect computers to networks. Network adapters convert digital signals from computers into analog signals that can be transmitted over physical media, such as copper wires or fiber optic cables.
• Routers and switches: Routers and switches are used to route and forward data packets between different networks. Routers and switches can support both digital and analog signaling.
• Modems: Modems are used to convert digital signals from computers into analog signals that can be transmitted over telephone lines or other physical media.

Differences between Analogue and Digital Signals

ANALOGUE	DIGITAL
Analogue signals are continuous signals that represent physical measurements. They are denoted by sine waves. They use a continuous range of values to represent information. They are time-varying and can be processed and transmitted better. They are more susceptible to electronic noise and distortion, which can degrade the quality of the signal.	Digital signals are discrete signals that represent data as a sequence of separate values at any point in time. They are denoted by square waves. They use discrete values (0 and 1) to represent information. They are represented as square waves or clock signals. They are less susceptible to noise compared to analog signals.

APPLICATIONS OF COMPUTER NETWORKING

• Communication: Computer networks allow people to communicate with each other over long distances. This can be done through email, instant messaging, video conferencing, and other applications.
• Data sharing: Computer networks allow users to share data and files with each other. This can be done through file sharing services, cloud storage, and other applications.
• Remote access: Computer networks allow users to access computers and data from remote locations. This can be done through virtual private networks (VPNs) and other applications.
• Collaboration: Computer networks allow users to collaborate on projects and tasks. This can be done through shared documents, project management tools, and other applications.
• Entertainment: Computer networks allow users to access entertainment content, such as movies, TV shows, music, and games. This can be done through streaming services, online gaming platforms, and other applications.
• Education: Computer networks allow students to access educational resources, such as online courses, libraries, and simulations. This can be done through distance learning platforms and other applications.
• Business: Computer networks are essential for businesses of all sizes. They allow businesses to communicate with customers, partners, and employees; share data and files; and collaborate on projects.
• Government: Computer networks are used by governments to provide services to citizens, such as healthcare, education, and transportation. They are also used to collect data and monitor activities.
• Military: Computer networks are used by the military to communicate with each other, share data, and control weapons systems.
• Research: Computer networks are used by researchers to collaborate on projects, share data, and access research resources.

ILLUSTRATED NETWORK TYPES AND DESIGNS

DISCUSS NETWORK TYPES AND TOPOLOGIES

NETWORK TYPES

Personal Area Network (PAN):

A personal area network (PAN) is a computer network for interconnecting electronic devices within an individual person's workspace. PANs are typically small networks that connect devices within a few feet of each other. PANs can be either wired or wireless.

Some examples of PANs include:

• A smartphone connected to a Bluetooth headset
• A laptop connected to a wireless mouse and keyboard
• A fitness tracker connected to a smartphone
• A smartwatch connected to a smartphone
• A smart home system connecting devices such as lights, thermostats, and door locks

PANs are used for a variety of purposes, including:

• Communication: PANs can be used to communicate between devices, such as between a smartphone and a Bluetooth headset.
• Data sharing: PANs can be used to share data between devices, such as between a laptop and a wireless printer.
• Control: PANs can be used to control devices, such as between a smartphone and a smartwatch.

PANs can be used to improve productivity, convenience, and safety. For example, a wireless mouse and keyboard can make it easier to use a laptop. A fitness tracker can help people stay motivated to exercise. A smart home system can help people save energy and improve security.

Here are some specific examples of how PANs are used in the real world:

• A student uses wireless headphones to listen to music while studying on their laptop.
• A business traveler uses a Bluetooth headset to make and receive hands-free calls while driving.
• A patient uses a smart watch to track their heart rate and activity level.
• A homeowner uses a smart home system to control the lights, thermostat, and door locks in their home.

1. Local Area Network (LAN):

A local area network (LAN) is a computer network that interconnects computers and peripheral devices within a limited geographic area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger geographic distance, but also generally involves leased telecommunication circuits.

Some examples of LANs include:

• A home network with a few computers, a printer, and a router
• A small business network with a dozen or so computers, a server, and a firewall
• A school network with hundreds of computers, multiple servers, and a variety of networking devices
• A large enterprise network with thousands of computers, multiple servers, and a complex network infrastructure

LANs are used for a variety of purposes, including:

• Resource sharing: LANs allow users to share resources such as files, printers, and storage devices. This can save money and improve efficiency.
• Communication: LANs allow users to communicate with each other using email, instant messaging, and video conferencing.
• Access to information: LANs allow users to access information from a variety of sources, such as the internet, databases, and other computers on the network.
• Collaboration: LANs allow users to collaborate on projects and share ideas.
• Entertainment: LANs allow users to access entertainment content such as streaming video, online games, and music.

Here are some specific examples of how LANs are used in the real world:

• A student uses a LAN to access the school's library database and print out a research paper.
• A group of employees at a small business use a LAN to share files and collaborate on a project.
• A company's customer service department uses a LAN to access a customer database and provide customer support.
• A university campus uses a LAN to provide students and faculty with access to the internet, email, and other online resources.

Benefits of using a LAN

There are many benefits to using a LAN, including:

• Resource sharing: LANs allow users to share resources such as files, printers, and storage devices. This can save money and improve efficiency.
• Communication: LANs allow users to communicate with each other using email, instant messaging, and video conferencing. This can save time and improve productivity.
• Access to information: LANs allow users to access information from a variety of sources, such as the internet, databases, and other computers on the network. This can help users to make better decisions and solve problems more effectively.
• Collaboration: LANs allow users to collaborate on projects and share ideas. This can help to improve the quality of work and reduce the time it takes to complete projects.
• Security: LANs can be used to improve the security of computer networks. For example, firewalls can be used to protect networks from unauthorized access and malware.

2. Wireless Local Area Network (WLAN)

A WLAN is a type of LAN that uses wireless technology to connect devices. WLANs are commonly used in homes, offices, and public places such as airports and coffee shops.

3. Campus Area Network (CAN):

A campus area network (CAN) is a computer network that interconnects multiple local area networks (LANs) within a limited geographic area such as a college or university campus, corporate campus, or hospital campus. CANs are typically larger than LANs but smaller than metropolitan area networks (MANs) and wide area networks (WANs).

Examples of CANs

• A university campus network with hundreds or even thousands of computers, multiple servers, and a variety of networking devices
• A corporate campus network with thousands of computers, multiple servers, and a complex network infrastructure
• A hospital campus network with thousands of devices, including computers, medical devices, and patient monitoring systems

Uses of CANs

• Resource sharing: CANs allow users to share resources such as files, printers, and storage devices. This can save money and improve efficiency.
• Communication: CANs allow users to communicate with each other using email, instant messaging, and video conferencing. This can save time and improve productivity.
• Access to information: CANs allow users to access information from a variety of sources, such as the internet, databases, and other computers on the network. This can help users to make better decisions and solve problems more effectively.
• Collaboration: CANs allow users to collaborate on projects and share ideas. This can help to improve the quality of work and reduce the time it takes to complete projects.
• Security: CANs can be used to improve the security of computer networks. For example, firewalls can be used to protect networks from unauthorized access and malware.

Real-World Examples of CANs

1. A student at a university uses the CAN to access the school's library database and print out a research paper.
2. A group of employees at a corporate campus use the CAN to share files and collaborate on a project.
3. A doctor at a hospital uses the CAN to access a patient's medical records and consult with other doctors about the patient's care.
4. CANs are an essential part of modern education and healthcare. They offer a number of benefits that can help organizations to improve efficiency, productivity, and security.

Metropolitan Area Network (MAN)

A metropolitan area network (MAN) is a computer network that interconnects users with computer resources in a geographic region of the size of a metropolitan area. This could be a single large city, multiple cities and towns, or any given large area with multiple buildings. A MAN is larger than a local area network (LAN) but smaller than a wide area network (WAN).

Examples of MANs

• A city's government network, which connects all of the city's offices and departments
• A university's network, which connects all of the university's buildings and campuses
• A hospital's network, which connects all of the hospital's buildings and facilities
• A large corporation's network, which connects all of the corporation's offices and facilities in a metropolitan area

Uses of MANs

• Resource sharing: MANs allow users to share resources such as files, printers, and storage devices across a large geographic area. This can save money and improve efficiency.
• Communication: MANs allow users to communicate with each other using email, instant messaging, and video conferencing. This can save time and improve productivity.
• Access to information: MANs allow users to access information from a variety of sources, such as the internet, databases, and other computers on the network. This can help users to make better decisions and solve problems more effectively.
• Collaboration: MANs allow users to collaborate on projects and share ideas across a large geographic area. This can help to improve the quality of work and reduce the time it takes to complete projects.
• Security: MANs can be used to improve the security of computer networks. For example, firewalls can be used to protect networks from unauthorized access and malware.

Real-World Examples of MANs

• A city's government uses a MAN to connect all of its offices and departments. This allows city employees to share files, communicate with each other, and access information from the city's databases.
• A university uses a MAN to connect all of its buildings and campuses. This allows students and faculty to share files, communicate with each other, and access the university's library database and other online resources.
• A hospital uses a MAN to connect all of its buildings and facilities. This allows doctors, nurses, and other healthcare professionals to share patient records, communicate with each other, and access the hospital's medical devices and patient monitoring systems.
• A large corporation uses a MAN to connect all of its offices and facilities in a metropolitan area. This allows employees to share files, communicate with each other, and access the corporation's databases and other online resources.

Wide Area Network (WAN)

A wide area network (WAN) is a computer network that connects two or more local area networks (LANs) across a large geographic area. WANs can span cities, countries, or even the entire world.

Examples of WANs

• The internet
• A corporate network that connects all of the corporation's offices in different cities around the world
• A government network that connects all of the government's offices in different cities around the country
• A university network that connects all of the university's campuses in different states

Uses of WANs

• Resource sharing: WANs allow users to share resources such as files, printers, and storage devices across a large geographic area. This can save money and improve efficiency.
• Communication: WANs allow users to communicate with each other using email, instant messaging, and video conferencing. This can save time and improve productivity.
• Access to information: WANs allow users to access information from a variety of sources, such as the internet, databases, and other computers on the network. This can help users to make better decisions and solve problems more effectively.
• Collaboration: WANs allow users to collaborate on projects and share ideas across a large geographic area. This can help to improve the quality of work and reduce the time it takes to complete projects.
• Security: WANs can be used to improve the security of computer networks. For example, firewalls can be used to protect networks from unauthorized access and malware.

Real-World Examples of WANs

• A company with offices in different cities uses a WAN to connect all of its offices. This allows employees in different offices to share files, communicate with each other, and access the company's databases and other online resources.
• A university with campuses in different states uses a WAN to connect all of its campuses. This allows students and faculty on different campuses to share files, communicate with each other, and access the university's library database and other online resources.
• A government agency with offices in different cities uses a WAN to connect all of its offices. This allows government employees in different offices to share files, communicate with each other, and access the government's databases and other online resources.

WANs are an essential part of the modern world. They allow organizations to connect their employees, students, and citizens to the resources they need across a large geographic area.

NETWORK TOPOLOGIES

Network topology refers to the physical or logical arrangement of nodes and connections in a network.

Point to Point (P2P)

Point-to-point topology is the easiest of all the network topologies. In this method, the network consists of a direct link between two computers.

Advantages

• This is faster and highly reliable than other types of connections since there is a direct connection.
• No need for a network operating system.
• Does not need an expensive server as individual workstations are used to access the files.
• No need for any dedicated network technicians because each user sets their permissions.

Disadvantages

• The biggest drawback is that it can only be used for small areas where computers are in close proximity.
• You can’t back up files and folders centrally.
• There is no security besides the permissions. Users often do not require to log onto their workstations.

Bus Topology

Bus topology uses a single cable which connects all the included nodes. The main cable acts as a spine for the entire network. One of the computers in the network acts as the computer server. When it has two endpoints, it is known as a linear bus topology.

Advantages

• Cost of the cable is very less as compared to other topology, so it is widely used to build small networks.
• Famous for LAN network because they are inexpensive and easy to install.
• It is widely used when a network installation is small, simple, or temporary.
• It is one of the passive topologies. So computers on the bus only listen for data being sent, that are not responsible for moving the data from one computer to others.

Disadvantages

• In case if the common cable fails, then the entire system will crash down.
• When network traffic is heavy, it develops collisions in the network.
• Whenever network traffic is heavy, or nodes are too many, the performance time of the network significantly decreases.
• Cables are always of a limited length.

Ring Topology

In a ring network, every device has exactly two neighboring devices for communication purposes. It is called a ring topology as its formation is like a ring. In this topology, every computer is connected to another computer. Here, the last node is combined with the first one. This topology uses a token to pass the information from one computer to another. In this topology, all the messages travel through a ring in the same direction.

Advantages

• Easy to install and reconfigure.
• Adding or deleting a device in ring topology needs you to move only two connections.
• Offers equal access to all the computers of the networks.
• Faster error checking and acknowledgment.

Disadvantages

• Troubleshooting process is difficult in a ring topology.
• Failure of one computer can disturb the whole network.
• Unidirectional traffic.
• Break in a single ring can risk the breaking of the entire network.
• Modern days high-speed LANs made this topology less popular.
• In the ring topology, signals are circulating at all times, which develops unwanted power consumption.
• It is very difficult to troubleshoot the ring network.
• Adding or removing the computers can disturb the network activity.

Star Topology

In the star topology, all the computers connect with the help of a hub. This cable is called a central node, and all other nodes are connected using this central node. It is most popular on LAN networks as they are inexpensive and easy to install.

Advantages

• Easy to troubleshoot, set up, and modify.
• Only those nodes are affected that have failed. Other nodes still work.
• Fast performance with few nodes and very low network traffic.
• In Star topology, addition, deletion, and moving of the devices are easy.

Disadvantages

• If the hub or concentrator fails, attached nodes are disabled.
• Cost of installation of star topology is costly.
• Heavy network traffic can sometimes slow the bus considerably.
• Performance depends on the hub’s capacity.
• A damaged cable or lack of proper termination may bring the network down.

Mesh Topology

The mesh topology has a unique network design in which each computer on the network connects to every other. It develops a P2P (point-to-point) connection between all the devices of the network. It offers a high level of redundancy, so even if one network cable fails, still data has an alternative path to reach its destination.

Types of Mesh Topology

• Partial Mesh Topology: In this type of topology, most of the devices are connected almost similarly as full topology. The only difference is that few devices are connected with just two or three devices.
• Full Mesh Topology: In this topology, every node or device is directly connected with each other.

Advantages

• The network can be expanded without disrupting current users.
• Need extra capable compared with other LAN topologies.
• No traffic problem as nodes have dedicated links.
• Dedicated links help you to eliminate the traffic problem.
• A mesh topology is robust.
• It has multiple links, so if any single route is blocked, then other routes should be used for data communication.
• P2P links make the fault identification isolation process easy.
• It helps you to avoid the chances of network failure by connecting all the systems to a central node.
• Every system has its privacy and security.

Disadvantages

• Installation is complex because every node is connected to every node.
• It is expensive due to the use of more cables. No proper utilization of systems.
• Complicated implementation.
• It requires more space for dedicated links.
• Because of the amount of cabling and the number of input-outputs, it is expensive to implement.
• It requires a large space to run the cables.

Tree Topology

Tree topologies have a root node, and all other nodes are connected which form a hierarchy. So it is also known as hierarchical topology. This topology integrates various star topologies together in a single bus, so it is known as a Star Bus topology. Tree topology is a very common network which is similar to a bus and star topology.

Advantages

• Failure of one node never affects the rest of the network.
• Node expansion is fast and easy.
• Detection of error is an easy process.
• It is easy to manage and maintain.

Disadvantages

• It is heavily cabled topology.
• If more nodes are added, then its maintenance is difficult.
• If the hub or concentrator fails, attached nodes are also disabled.

Hybrid Topology

Hybrid topology combines two or more topologies. You can see in the above architecture in such a manner that the resulting network does not exhibit one of the standard topologies. For example, as you can see in the above image that in an office in one department, Star and P2P topology is used. A hybrid topology is always produced when two different basic network topologies are connected.

Advantages

• Offers the easiest method for error detecting and troubleshooting
• Highly effective and flexible networking topology
• It is scalable so you can increase your network size

Disadvantages

• The design of hybrid topology is complex
• It is one of the costliest processes

IDENTIFY APPROPRIATE NETWORKING EQUIPMENT

Transmission media refers to the physical paths through which data is transmitted from one location to another. There are different types of transmission media, each with its own characteristics, advantages, and limitations. Here are some of the most common types of transmission media:

Twisted Pair Cable:

Twisted pair cable is a type of copper cable that is used for telecommunications and computer networking. It consists of two insulated copper wires that are twisted together around a central core. The twisting of the wires helps to reduce electromagnetic interference (EMI) and crosstalk, which can improve the quality of the signal.

Twisted pair cable is the most common type of cable used for computer networks. It is relatively inexpensive and easy to install. It is also available in a variety of speeds and bandwidths, making it suitable for a wide range of applications.

Advantages of Twisted Pair Cable:

• Inexpensive: Twisted pair cable is one of the least expensive types of network cabling available.
• Easy to install: Twisted pair cable is relatively easy to install and terminate.
• Flexible: Twisted pair cable is flexible and easy to bend, making it easy to route through tight spaces.
• Widely available: Twisted pair cable is widely available from a variety of vendors.
• Supported by a wide range of devices: Twisted pair cable is supported by a wide range of networking devices, including routers, switches, and computers.
• Supports high speeds and bandwidths: Twisted pair cable can support high speeds and bandwidths, making it suitable for a wide range of applications.
• Low EMI and crosstalk: The twisting of the wires in twisted pair cable helps to reduce EMI and crosstalk, which can improve the quality of the signal.
• Durable: Twisted pair cable is durable and can withstand a lot of wear and tear.

Disadvantages of Twisted Pair Cable:

• Susceptible to noise and interference: Twisted pair cable is more susceptible to noise and interference than other types of network cabling, such as fiber optic cable.
• Limited distance: Twisted pair cable has a limited distance that it can transmit a signal without degradation.
• Susceptible to physical damage: Twisted pair cable is more susceptible to physical damage than other types of network cabling, such as fiber optic cable.
• Requires shielding: Twisted pair cable that is used in noisy environments may require shielding to reduce noise and interference.
• Can be difficult to troubleshoot: Twisted pair cable can be difficult to troubleshoot, especially if it is installed in a complex network.
• Lower bandwidth than fiber optic cable: Twisted pair cable has a lower bandwidth than fiber optic cable, which limits its suitability for some applications.
• Not as secure as fiber optic cable: Twisted pair cable is not as secure as fiber optic cable, as it can be tapped or intercepted more easily.
• Can be difficult to install in some locations: Twisted pair cable can be difficult to install in some locations, such as underground or underwater.

Unshielded twisted pair (UTP) is the most common type of twisted pair cable. It is used in a wide range of applications, including telephone networks, computer networks, and security systems.

Shielded twisted pair (STP) is a type of twisted pair cable that is shielded to reduce noise and interference. It is typically used in noisy environments, such as factories and warehouses.

STP is more expensive than UTP, but it offers better performance and reliability. It is also more secure than UTP, as it is more difficult to tap or intercept.

Twisted pair cable is a versatile and reliable type of network cabling. It is suitable for a wide range of applications, from small home networks to large enterprise networks.

Coaxial Cable:

Coaxial cable is a type of cable that consists of a central copper conductor surrounded by a layer of insulation and a braided metal shield. The shield helps to reduce electromagnetic interference (EMI) and crosstalk, which can improve the quality of the signal.

Coaxial cable was once the most common type of cable used for computer networks, but it has been largely replaced by twisted pair cable in recent years. However, coaxial cable is still used in some applications, such as cable television and satellite TV.

Advantages of Coaxial Cable:

1. High bandwidth: Coaxial cable can support high bandwidth, making it suitable for demanding applications such as video streaming and high-speed internet access.
2. Low signal loss: Coaxial cable has low signal loss, which means that it can transmit signals over long distances without significant degradation.
3. Durable: Coaxial cable is durable and can withstand a lot of wear and tear.
4. Easy to install: Coaxial cable is relatively easy to install and terminate.
5. Widely available: Coaxial cable is widely available from a variety of vendors.
6. Supported by a wide range of devices: Coaxial cable is supported by a wide range of devices, including cable TV modems, satellite TV receivers, and high-speed internet modems.
7. Relatively inexpensive: Coaxial cable is relatively inexpensive, especially compared to fiber optic cable.
8. Resistant to moisture and corrosion: Coaxial cable is resistant to moisture and corrosion, making it suitable for outdoor use.

Disadvantages of Coaxial Cable:

1. Susceptible to bending and kinking: Coaxial cable is susceptible to bending and kinking, which can damage the cable and reduce its performance.
2. Requires special connectors: Coaxial cable requires special connectors to terminate the ends of the cable.
3. Not as flexible as twisted pair cable: Coaxial cable is not as flexible as twisted pair cable, making it more difficult to route through tight spaces.
4. Can be difficult to troubleshoot: Coaxial cable can be difficult to troubleshoot, especially if it is installed in a complex network.
5. Not as secure as fiber optic cable: Coaxial cable is not as secure as fiber optic cable, as it can be tapped or intercepted more easily.
6. Can be difficult to install in some locations: Coaxial cable can be difficult to install in some locations, such as underground or underwater.

Fiber Optic Cable

Fiber optic cable is a type of cable that uses light to transmit data. It consists of a thin core of glass or plastic that is surrounded by a cladding. The cladding helps to reflect the light back into the core, which allows the light to travel over long distances without attenuation.

Fiber optic cable is the fastest and most reliable type of network cabling available. It is used in a wide range of applications, including telecommunications networks, data centers, and enterprise networks.

Advantages of Fiber Optic Cable:

1. Extremely high bandwidth: Fiber optic cable can support extremely high bandwidth, making it suitable for demanding applications such as video streaming, high-speed internet access, and cloud computing.
2. Low signal loss: Fiber optic cable has very low signal loss, which means that it can transmit signals over very long distances without significant degradation.
3. Immune to EMI and crosstalk: Fiber optic cable is immune to electromagnetic interference (EMI) and crosstalk, which can improve the quality and reliability of the signal.
4. Secure: Fiber optic cable is very difficult to tap or intercept, making it a secure choice for transmitting sensitive data.
5. Durable: Fiber optic cable is durable and can withstand a lot of wear and tear.
6. Lightweight and flexible: Fiber optic cable is lightweight and flexible, making it easy to install and route.

Disadvantages of Fiber Optic Cable:

1. Expensive: Fiber optic cable is more expensive than other types of network cabling, such as twisted pair cable and coaxial cable.
2. Requires special connectors and tools: Fiber optic cable requires special connectors and tools to terminate the ends of the cable.
3. Difficult to troubleshoot: Fiber optic cable can be difficult to troubleshoot, especially if it is installed in a complex network.
4. Susceptible to physical damage: Fiber optic cable is susceptible to physical damage, such as cuts and breaks.

Wireless Transmission

Wireless transmission is the transmission of data without the use of physical wires or cables. It is used in a wide range of applications, including computer networks, telecommunications networks, and consumer electronics.

Advantages of Wireless Transmission

• Mobility: Wireless transmission allows devices to communicate with each other without being physically connected. This makes it possible to use mobile devices such as smartphones, laptops, and tablets.
• Scalability: Wireless networks are easily scalable to support a large number of users and devices.
• Flexibility: Wireless networks can be deployed in a variety of environments, including indoor, outdoor, and remote locations.
• Ease of installation: Wireless networks are typically easier to install and maintain than wired networks.
• Cost: Wireless networks can be more cost-effective than wired networks, especially in areas where it is difficult or expensive to install wires.

Disadvantages of Wireless Transmission

• Security: Wireless networks are more vulnerable to security threats than wired networks.
• Range: Wireless networks have a limited range, and the signal can be degraded by environmental factors such as distance, obstacles, and interference.
• Bandwidth: Wireless networks typically have lower bandwidth than wired networks.
• Reliability: Wireless networks can be less reliable than wired networks, as the signal can be affected by environmental factors such as weather and interference.

Examples of Wireless Transmission

• Wi-Fi: Wi-Fi is a wireless networking technology that uses radio waves to connect devices to the internet.
• Bluetooth: Bluetooth is a wireless technology that is used to connect devices to each other over short distances.
• Cellular networks: Cellular networks are used to provide mobile phone service and mobile internet access.
• Satellite communication: Satellite communication is used to transmit data over long distances using satellites.
• Radio: Radio is used to transmit audio and video signals over the air.

Connectivity Devices

Connectivity devices are hardware devices that are used to connect different parts of a network together. They are essential for ensuring that data is transmitted efficiently and securely across the network. Here are some of the most common connectivity devices:

1. Firewall:

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and an untrusted external network, such as the internet. Firewalls can be implemented in hardware, software, or a combination of both.

Hardware firewalls are physical devices that sit between the internal network and the internet. They typically have multiple ports that are used to connect to different networks. Hardware firewalls are typically more expensive than software firewalls, but they offer better performance and security.

Software firewalls are programs that are installed on individual computers or servers. They typically use a combination of packet filtering and stateful inspection to monitor and control network traffic. Software firewalls are less expensive than hardware firewalls, but they can have a negative impact on the performance of the computer or server that they are installed on.

Both hardware and software firewalls can be configured to allow or block specific types of traffic, such as web traffic, email traffic, and file transfer traffic. Firewalls can also be used to create VPNs (virtual private networks) that allow users to securely access resources on a remote network.

Here are some examples of how firewalls can be used to protect a network:

• Block malicious traffic: Firewalls can be used to block malicious traffic, such as malware and viruses, from entering the network.
• Prevent unauthorized access: Firewalls can be used to prevent unauthorized access to the network from the internet.
• Protect sensitive data: Firewalls can be used to protect sensitive data, such as customer records and financial data, from being accessed by unauthorized users.
• Comply with regulations: Firewalls can be used to help organizations comply with regulations that require them to protect certain types of data.

2. Router:

A router is a network device that connects two or more computer networks. It forwards data packets between networks based on their IP addresses. Routers are used in a wide variety of networks, from small home networks to large enterprise networks.

Operation

Routers operate at the network layer (layer 3) of the OSI model. The network layer is responsible for routing packets between different networks. Routers use a variety of routing protocols to determine the best path to forward packets to their destination.

Main Functions of a Router

• Routing: Routers forward data packets between networks based on their IP addresses.
• NAT (Network Address Translation): Routers can be used to perform NAT, which translates IP addresses between different networks. This allows multiple devices on a private network to share a single public IP address.
• DHCP (Dynamic Host Configuration Protocol): Routers can be used to assign IP addresses to devices on a network using DHCP.
• Firewall: Routers can be used to implement a firewall to protect the network from unauthorized access and malicious traffic.

Routers are essential devices for any network that connects to the internet. They provide a number of important functions, including routing packets, NAT, DHCP, and firewall protection.

Examples of Router Usage

• Home Networks: Routers are used in home networks to connect multiple devices, such as computers, smartphones, and smart TVs, to the internet.
• Business Networks: Routers are used in business networks to connect different departments and offices to each other and to the internet.
• Internet Service Providers (ISPs): ISPs use routers to connect their customers to the internet.
• Wide Area Networks (WANs): WANs use routers to connect networks in different locations together.

3. Network Switch

A network switch is a networking device that connects multiple devices on a computer network. Switches operate at the data link layer (layer 2) of the OSI model. The data link layer is responsible for transmitting and receiving data frames between devices on the same network.

Switches work by maintaining a MAC address table. The MAC address table is a database that maps MAC addresses to ports on the switch. When a switch receives a frame, it looks up the MAC address of the destination device in the MAC address table. If the destination device is connected to the switch, the switch forwards the frame to the appropriate port. If the destination device is not connected to the switch, the switch broadcasts the frame to all of its ports.

Main Functions of a Network Switch

• Connecting devices: Switches allow multiple devices to be connected to a single network.
• Improving performance: Switches can improve the performance of a network by reducing collisions. Collisions occur when two devices try to transmit data at the same time. Switches can prevent collisions by buffering frames and transmitting them one at a time.
• Segmenting networks: Switches can be used to segment a network into multiple subnets. This can improve security and performance by isolating different types of traffic on different subnets.

Switches are used in a wide variety of networks, from small home networks to large enterprise networks. They are an essential part of most modern networks.

Examples of Network Switch Usage

• Home networks: Switches are used in home networks to connect multiple devices, such as computers, smartphones, and smart TVs, to each other.
• Business networks: Switches are used in business networks to connect different departments and offices to each other.
• Data centers: Switches are used in data centers to connect servers and other networking equipment to each other.
• Wide area networks (WANs): WANs use switches to connect networks in different locations together.

A switch is a device that connects multiple devices together within a network and directs data traffic between them. It is used to provide high-speed connectivity between devices within a network.

4. A Network Hub

A network hub is a networking device that connects multiple devices on a computer network. It works at the physical layer (layer 1) of the OSI model. The physical layer is responsible for transmitting and receiving raw bits of data over a physical medium such as a copper cable or fiber optic cable.

Functionality

When a hub receives data from one device, it forwards the data to all of the other devices connected to the hub. This means that all devices on a hub share the same bandwidth.

Advantages and Disadvantages

Hubs are relatively inexpensive and easy to install. However, they are not as efficient as switches because they can cause collisions. Collisions occur when two devices try to transmit data at the same time.

Current Usage

Hubs are not used as much as they once were because switches offer better performance and are more affordable. However, hubs are still used in some applications, such as small home networks and legacy networks.

Examples of Network Hubs Usage

• Small home networks: Hubs can be used in small home networks to connect a few devices, such as computers and printers, to each other.
• Legacy networks: Hubs are still used in some legacy networks that were installed before switches became popular.
• Testing environments: Hubs are sometimes used in testing environments to simulate a network with a lot of collisions.

Bridge

A bridge is a network device that connects two or more network segments.

It operates at the data link layer (layer 2) of the OSI model. The data link layer is responsible for transmitting and receiving data frames between devices on the same network.

How Bridges Work

Bridges work by filtering and forwarding frames based on their MAC addresses. When a bridge receives a frame, it looks up the MAC address of the destination device in its forwarding table. If the destination device is on the same network segment as the bridge, the bridge drops the frame. If the destination device is on a different network segment, the bridge forwards the frame to the appropriate network segment.

Benefits of Using Bridges

• Improve the performance of a network by segmenting the network into multiple subnets.
• Isolate different types of traffic on different subnets, which can improve security and performance.
• Extend the range of a network by connecting two or more networks that are located far apart.

6. Modem:

A modem is a device that converts digital signals from a computer into analog signals that can be transmitted over a telephone line or cable TV line. It also converts analog signals received over a telephone line or cable TV line into digital signals that can be understood by a computer.

Modem Operation

Modems operate at the physical layer (layer 1) of the OSI model. The physical layer is responsible for transmitting and receiving raw bits of data over a physical medium such as a copper cable or fiber optic cable.

Types of Modems

There are two main types of modems:

• Dial-up modems: Dial-up modems use a telephone line to connect to the internet. They are the oldest and slowest type of modem, but they are still used in some areas where there is no broadband internet access.
• Broadband modems: Broadband modems use a cable TV line or fiber optic line to connect to the internet. They offer much faster speeds than dial-up modems.

Current Usage

Broadband modems are the most common type of modem used today. They offer speeds that are fast enough for most home and business needs.

A Wireless Access Point (AP)

A wireless access point (AP) is a networking device that connects wireless devices to a wired network. It works by converting the digital signals from the wired network into radio waves that can be transmitted to wireless devices. Wireless APs are typically used in homes, businesses, and other locations where wireless internet access is needed.

Operation of Wireless APs

Wireless APs operate at the data link layer (layer 2) of the OSI model. The data link layer is responsible for transmitting and receiving data frames between devices on the same network.

Uses of Wireless APs

• Provide wireless internet access to devices such as laptops, smartphones, and tablets.
• Extend the range of a wireless network.
• Create multiple wireless networks with different security settings.

Importance of Wireless APs

Wireless APs are an essential part of many modern networks. They allow us to connect to the internet and to each other from anywhere in a building or even a large campus.

Media Converter

A Media Converter

A media converter is a networking device that converts one type of network media to another. For example, it can convert copper cable to fiber optic cable, or vice versa. Media converters are used to extend the reach of a network, or to connect networks that use different types of media.

Operation

Media converters operate at the physical layer (layer 1) of the OSI model. The physical layer is responsible for transmitting and receiving raw bits of data over a physical medium such as a copper cable or fiber optic cable.

Typical Scenarios for Media Converters

• To extend the reach of a network: Copper cable has a limited transmission distance, so media converters can be used to extend the reach of a copper-based network by converting the copper signal to fiber optic signal and transmitting it over fiber optic cable.
• To connect networks that use different types of media: For example, a media converter can be used to connect a copper-based network to a fiber optic-based network.

A Wireless Range Extender

A wireless range extender, also known as a Wi-Fi extender, is a device that amplifies and retransmits a Wi-Fi signal, extending its range. This can be useful for homes or businesses with large areas, or for homes or businesses with thick walls or other obstacles that can interfere with Wi-Fi signals.

How Wireless Range Extenders Work

Wireless range extenders work by connecting to an existing Wi-Fi network and creating a new Wi-Fi network with the same name and password. This allows devices to connect to the Wi-Fi network that has the strongest signal, whether it is the original network or the extender's network.

Key Features

• Amplifies Wi-Fi signal
• Extends coverage area
• Connects to existing networks
• Creates a new network with the same credentials

A Voice over Internet Protocol (VoIP) Endpoint

A Voice over Internet Protocol (VoIP) endpoint is a device that allows users to make and receive voice calls over the internet. VoIP endpoints can be used in a variety of settings, including homes, businesses, and call centers.

Types of VoIP Endpoints

• Hardphones: Hardphones are dedicated devices that are designed for VoIP calling. They typically have a handset, speakerphone, and keypad. Hardphones are often used in businesses and call centers.
• Softphones: Softphones are software applications that can be installed on a computer or mobile device. Softphones allow users to make and receive VoIP calls using their computer or mobile device's microphone and speakers. Softphones are often used in homes and small businesses.

VoIP endpoints use a variety of technologies to transmit voice calls over the internet. The most common technology is Session Initiation Protocol (SIP). SIP is a signaling protocol that allows devices to establish and manage VoIP calls.

Advantages of VoIP Endpoints

• Cost: VoIP calls are typically less expensive than traditional telephone calls, especially for long-distance calls.
• Features: VoIP endpoints offer a variety of features that are not available with traditional telephone service, such as video calling, conference calling, and call forwarding.
• Flexibility: VoIP endpoints can be used from anywhere with an internet connection. This makes them ideal for remote workers and businesses with multiple locations.

Network Operating Systems

A Network Operating System (NOS) is a specialized operating system for a network device such as a router, switch, or firewall. It is designed to enable workstations and other hardware connected on a local network. Network operating systems exist in contrast with traditional operating systems that are designed for individual machines without network capabilities in mind.

The main advantage of a network operating system is that it allows workstations easy access to other machines on the network for the purposes of file and application sharing, or utility access for services like printing. Businesses use network operating systems to save time on workstation set up as applications can easily be shared to new machines, and utilities like printers won’t have to be set up manually for each workstation.

Functions of Network Operating Systems

• Establishing and maintaining user profiles on the network
• Enabling file sharing
• Providing access to printers on a private network, a local area network, or other networks with many devices

Examples of Network Operating Systems

• Windows Server
• Linux distributions (e.g., Ubuntu Server, Debian Server, CentOS Server)
• macOS Server
• FreeBSD
• OpenBSD
• NetBSD
• Novell Open Enterprise Server
• Sun Solaris
• AIX
• HP-UX
• IBM i
• z/OS

Common Features of Network Operating Systems

• User authentication and authorization
• File and print sharing
• Network resource management
• Network security
• Network monitoring and management

Usage of Network Operating Systems

• In a home network, a network operating system can be used to share files and printers between multiple computers.
• In a business network, a network operating system can be used to provide user authentication and authorization, manage network resources, and implement network security.
• In a school network, a network operating system can be used to provide student access to educational resources and to manage student accounts.
• In a government agency network, a network operating system can be used to provide secure access to government data and applications.

Transmission Modes

Data transmission modes refer to the way data is transmitted between devices in a network. There are different types of data transmission modes, each with its own characteristics, advantages, and limitations.

Broadband

Broadband is a type of internet connection that offers high speeds, typically much faster than traditional dial-up internet. Broadband connections are always on, meaning that you don't have to connect each time you want to use the internet.

Technologies Used in Broadband

• DSL (digital subscriber line): DSL uses existing telephone lines to deliver broadband speeds.
• Cable: Cable internet uses the same coaxial cables that are used for cable TV to deliver broadband speeds.
• Fiber optic: Fiber optic internet uses fiber optic cables to deliver the fastest broadband speeds available.
• Satellite: Satellite internet uses satellites to deliver broadband speeds to remote areas where other broadband options are not available.

Uses of Broadband

• Streaming video and music
• Online gaming
• Working from home
• Distance learning

Baseband

Baseband is a type of signal that represents data in its original form, without any modulation. Baseband signals are typically used for short-distance communication, such as within a computer or between two devices connected by a cable.

Applications of Baseband Signals

• Computer networks
• Telecommunications
• Consumer electronics

Advantages and Disadvantages of Baseband Signals

• Advantages:
  • Simple to implement
  • Can be used for a variety of applications
  • Relatively inexpensive
• Disadvantages:
  • Not as efficient as modulated signals for long-distance transmission
  • More susceptible to noise and interference

Broadband versus Baseband

• Broadband signals can carry more data than baseband signals.
• Broadband signals are more resistant to noise and interference than baseband signals.
• Broadband signals are more expensive to implement than baseband signals.

Characteristic	Broadband	Baseband
Signal type	Analog	Digital
Modulation	Yes	No
Transmission distance	Long	Short
Susceptibility to noise and interference	Less	More
Cost	Higher	Lower
Applications	Internet, cable TV, satellite TV, cellular networks	Computer networks, telecommunications networks, consumer electronics

SYNCHRONOUS

Synchronous transmission is a type of data transmission in which data is sent in a continuous stream at a constant rate. The sender and receiver are synchronized using a common clock signal, which ensures that the data is received correctly.

Synchronous transmission is often used for applications where reliable and timely delivery of data is critical, such as voice over IP (VoIP), video streaming, and financial transactions. It is also used in industrial control systems and other critical applications.

Synchronous transmission is typically implemented using a variety of technologies, including:

• Serial interfaces: Serial interfaces, such as RS-232 and USB, use synchronous transmission to send data between devices.
• T1 and T3 lines: T1 and T3 lines are high-speed digital circuits that use synchronous transmission to transmit data over long distances.
• SONET and SDH: SONET (Synchronous Optical Network) and SDH (Synchronous Digital Hierarchy) are standards for optical transmission that use synchronous transmission to send data over fiber optic cables.

Synchronous transmission has a number of advantages over asynchronous transmission, including:

• Higher data rates: Synchronous transmission can achieve higher data rates than asynchronous transmission because it does not require start and stop bits between characters.
• More reliable: Synchronous transmission is more reliable than asynchronous transmission because the sender and receiver are synchronized, which helps to prevent errors.
• More efficient: Synchronous transmission is more efficient than asynchronous transmission because it does not waste bandwidth on start and stop bits.

However, synchronous transmission also has some disadvantages, including:

• More complex: Synchronous transmission is more complex to implement than asynchronous transmission because it requires a common clock signal.
• More expensive: Synchronous transmission is more expensive to implement than asynchronous transmission because it requires more complex equipment.

ASYNCHRONOUS

Asynchronous transmission is a type of data transmission in which data is sent one character at a time, with start and stop bits between characters. The sender and receiver do not need to be synchronized, which makes it simpler to implement and less expensive than synchronous transmission.

Asynchronous transmission is often used for applications where data does not need to be delivered in real time, such as email, file transfer, and web browsing. It is also used in low-speed applications, such as serial console connections.

Asynchronous transmission is typically implemented using a variety of technologies, including:

• Serial interfaces: Serial interfaces, such as RS-232 and USB, can be used for asynchronous transmission.
• Dial-up modems: Dial-up modems use asynchronous transmission to send and receive data over telephone lines.
• Ethernet: Ethernet networks can be configured to use asynchronous transmission, but this is not common.

Asynchronous transmission has a number of advantages over synchronous transmission, including:

• Simpler to implement: Asynchronous transmission is simpler to implement than synchronous transmission because it does not require a common clock signal.
• Less expensive: Asynchronous transmission is less expensive to implement than synchronous transmission because it requires less complex equipment.
• More flexible: Asynchronous transmission is more flexible than synchronous transmission because it does not require the sender and receiver to be synchronized.

However, asynchronous transmission also has some disadvantages, including:

• Lower data rates: Asynchronous transmission cannot achieve the same data rates as synchronous transmission because it requires start and stop bits between characters.
• Less reliable: Asynchronous transmission is less reliable than synchronous transmission because the sender and receiver are not synchronized, which can lead to errors.
• Less efficient: Asynchronous transmission is less efficient than synchronous transmission because it wastes bandwidth on start and stop bits.

Synchronous versus Asynchronous

Synchronous transmission is a type of data transmission in which data is transmitted in a continuous stream, while asynchronous transmission is a type of data transmission in which data is transmitted in discrete packets. Synchronous transmission is used for high-speed data transmission, while asynchronous transmission is used for low-speed data transmission.

SIMPLEX

Simplex transmission is a type of communication in which information flows in one direction only. The sender can only send data, and the receiver can only receive data. The receiver cannot reply to the sender.

Simplex transmission is often used in applications where feedback or response is not required, such as broadcasting or surveillance. Here are some examples of simplex transmission:

• Radio and television broadcasting
• One-way pagers
• Fire alarm systems
• CCTV cameras
• Traffic monitoring systems
• Spacecraft telemetry

Simplex transmission has a number of advantages, including:

• Simplicity: Simplex transmission is the simplest type of communication to implement.
• Reliability: Simplex transmission is the most reliable type of communication because it does not require any interaction between the sender and receiver.
• Efficiency: Simplex transmission is the most efficient type of communication because it uses all of the available bandwidth to send data in one direction.

However, simplex transmission also has some disadvantages, including:

• One-way communication: Simplex transmission only allows for one-way communication, which can be limiting in some cases.
• Lack of feedback: Simplex transmission does not provide any feedback to the sender, which can make it difficult to troubleshoot problems.

HALF DUPLEX

Half-duplex transmission is a type of communication in which information can flow in both directions, but only one direction at a time. The sender and receiver can both send and receive data, but they cannot do so at the same time.

Half-duplex transmission is often used in applications where two-way communication is needed, but where it is not necessary to send and receive data simultaneously. Here are some examples of half-duplex transmission:

• Walkie-talkies
• Two-way radios
• Cordless phones
• Ethernet networks
• Satellite communication systems

Half-duplex transmission has a number of advantages, including:

• Two-way communication: Half-duplex transmission allows for two-way communication, which is essential for many applications.
• Efficiency: Half-duplex transmission is more efficient than simplex transmission because it allows for two-way communication without requiring a dedicated channel for each direction.
• Cost: Half-duplex transmission is less expensive than full-duplex transmission because it only requires one channel for communication in both directions.

However, half-duplex transmission also has some disadvantages, including:

• One-way communication at a time: Half-duplex transmission only allows for one-way communication at a time, which can be limiting in some cases.
• Collisions: Half-duplex transmission can be susceptible to collisions, which occur when two devices try to send data at the same time.

FULL DUPLEX

Full-duplex transmission is a type of communication in which information can flow in both directions simultaneously. The sender and receiver can both send and receive data at the same time.

Full-duplex transmission is often used in applications where two-way communication is needed and where it is necessary to send and receive data simultaneously. Here are some examples of full-duplex transmission:

• Telephone networks
• Cellular networks
• Ethernet networks
• Fiber optic networks
• Satellite communication systems

Full-duplex transmission has a number of advantages, including:

• Two-way communication: Full-duplex transmission allows for two-way communication, which is essential for many applications.
• Simultaneous transmission and reception: Full-duplex transmission allows devices to send and receive data simultaneously, which can improve performance and efficiency.
• Reduced latency: Full-duplex transmission can reduce latency in communication systems because devices do not have to wait for each other to finish transmitting before they can begin transmitting themselves.

However, full-duplex transmission also has some disadvantages, including:

• Cost: Full-duplex transmission is more expensive than half-duplex transmission because it requires two dedicated channels for communication in both directions.
• Complexity: Full-duplex transmission is more complex to implement than half-duplex transmission because it requires additional hardware and software.

DESCRIBE INTERNETWORKING TECHNOLOGIES

DESCRIBE CIRCUIT SWITCHING, MESSAGE SWITCHING, PACKET SWITCHING, NARROWBAND AND BROADBAND NETWORKS

CIRCUIT SWITCHING:

Circuit switching is a type of network technology that establishes a dedicated communication channel between two devices for the duration of the call or session. This is in contrast to packet switching, which breaks down messages into smaller packets and sends them over the network independently of each other.

Circuit switching is typically used for real-time communication applications such as voice and video calls, as it guarantees a constant bandwidth and low latency. It is also used for some high-speed data applications, such as dedicated lines between businesses.

Here is how circuit switching works:

1. The calling device sends a request to the network to establish a circuit connection with the called device.
2. The network checks to see if the called device is available and if there is a circuit available between the two devices.
3. If the called device is available and there is a circuit available, the network establishes the connection.
4. The two devices can now communicate with each other over the dedicated circuit.
5. When the communication session is over, either device can send a request to the network to terminate the circuit connection.

Circuit switching has a number of advantages, including:

• Guaranteed bandwidth: Circuit switching guarantees a constant bandwidth for the duration of the call or session. This is important for real-time communication applications, such as voice and video calls, as it ensures that the quality of the communication is not degraded.
• Low latency: Circuit switching has low latency, which means that there is very little delay between the time that a device sends a signal and the time that the other device receives it. This is also important for real-time communication applications.
• Reliability: Circuit switching is a very reliable technology. Once a circuit connection is established, the two devices can communicate with each other without any interruption.

However, circuit switching also has some disadvantages, including:

• Inefficiency: Circuit switching can be inefficient because it dedicates a circuit to each call or session, even if the circuit is not being used to its full capacity.
• Cost: Circuit switching can be more expensive than packet switching because it requires the network to dedicate resources to each call or session.

MESSAGE SWITCHING:

Message switching is a network technology that stores and forwards messages between devices. It is in contrast to circuit switching, which establishes a dedicated communication channel between two devices for the duration of the call or session.

Message switching is typically used for applications where real-time communication is not required, such as email, file transfer, and messaging. It is also used for some high-speed data applications, such as data transmission between servers.

Here is how message switching works:

1. The sender device sends a message to the network.
2. The network stores the message in a buffer.
3. When the network has resources available, it forwards the message to the destination device.
4. The destination device receives the message and stores it in a buffer.
5. When the destination device is ready, it delivers the message to the recipient.

Message switching has a number of advantages, including:

• Efficiency: Message switching is more efficient than circuit switching because it does not require the network to dedicate a circuit to each message. Instead, the network can multiplex multiple messages over a single circuit.
• Cost: Message switching is less expensive than circuit switching because it does not require the network to dedicate resources to each message.
• Flexibility: Message switching is more flexible than circuit switching because it does not require the sender and receiver to be available at the same time. Instead, the network can store and forward messages when convenient.

However, message switching also has some disadvantages, including:

• Latency: Message switching can have higher latency than circuit switching because the network has to store and forward messages.
• Reliability: Message switching is less reliable than circuit switching because there is a risk that messages can be lost or corrupted in transit.

3. PACKET SWITCHING:

Packet switching is a network technology that breaks down messages into smaller packets and sends them over the network independently of each other. This is in contrast to circuit switching, which establishes a dedicated communication channel between two devices for the duration of the call or session.

Packet switching is the most common network technology used today. It is used in the Internet, as well as in many other types of networks, such as local area networks (LANs) and wide area networks (WANs).

Here is how packet switching works:

1. The sender device breaks down the message into smaller packets.
2. Each packet is assigned a header, which contains information about the source device, the destination device, and the sequence number of the packet.
3. The packets are sent over the network independently of each other.
4. The packets can take different routes through the network, and they may arrive at the destination device out of order.
5. The destination device reassembles the packets in the correct order to form the original message.

Packet switching has a number of advantages over circuit switching, including:

• Efficiency: Packet switching is more efficient than circuit switching because it does not require the network to dedicate resources to each message. Instead, the network can multiplex multiple messages over a single circuit.
• Flexibility: Packet switching is more flexible than circuit switching because it does not require the sender and receiver to be available at the same time. Instead, the network can store and forward packets when convenient.
• Scalability: Packet switching is more scalable than circuit switching because it can support a large number of users and devices without requiring a dedicated circuit for each one.

However, packet switching also has some disadvantages, including:

• Latency: Packet switching can have higher latency than circuit switching because the network has to store and forward packets.
• Reliability: Packet switching is less reliable than circuit switching because there is a risk that packets can be lost or corrupted in transit.

NARROWBAND NETWORKS:

Narrowband networks are communication networks that have a limited bandwidth. This means that they can only transmit a small amount of data at a time. Narrowband networks are often used for applications that do not require a lot of data, such as voice calls, text messaging, and email.

Narrowband networks can be implemented using a variety of technologies, including:

• Dial-up modems: Dial-up modems use telephone lines to transmit data. Dial-up modems have a very limited bandwidth, typically around 56 kilobits per second (Kbps).
• Cellular networks: Cellular networks use radio waves to transmit data. Cellular networks have a higher bandwidth than dial-up modems, typically around 1 megabit per second (Mbps).
• Low-power wide-area networks (LPWANs): LPWANs are a type of cellular network that is designed for low-power devices, such as sensors and smart meters. LPWANs have a very low bandwidth, typically around 100 kilobits per second (Kbps).

Narrowband networks have a number of advantages over broadband networks:

• Cost: Narrowband networks are less expensive to implement and operate than broadband networks.
• Coverage: Narrowband networks have a wider coverage area than broadband networks.
• Power consumption: Narrowband networks consume less power than broadband networks.

However, narrowband networks also have some disadvantages:

• Bandwidth: Narrowband networks have a lower bandwidth than broadband networks.
• Speed: Narrowband networks are slower than broadband networks.
• Latency: Narrowband networks have higher latency than broadband networks.

Overall, narrowband networks are a good choice for applications that do not require a lot of data and where cost, coverage, and power consumption are important factors. However, they are not a good choice for applications that require a lot of data or high-speed transmission.

Here are some examples of how narrowband networks are used:

• Voice calls: Voice calls are typically transmitted over narrowband networks, such as cellular networks.
• Text messaging: Text messages are typically transmitted over narrowband networks, such as cellular networks.
• Email: Email messages are typically transmitted over narrowband networks, such as cellular networks.
• Machine-to-machine (M2M) communication: M2M communication is the communication between devices, such as sensors and smart meters. M2M communication is typically transmitted over narrowband networks, such as LPWANs.

BROADBAND NETWORKS:

Baseband is a type of signal that represents data in its original form, without any modulation. Baseband signals are typically used for short-distance communication, such as within a computer or between two devices connected by a cable.

Baseband signals can be analog or digital. Analog baseband signals are used in applications such as voice communication, while digital baseband signals are used in applications such as computer networking.

Baseband signals have a number of advantages, including:

• Simplicity: Baseband signals are simple to generate and transmit.
• Cost: Baseband signals are relatively inexpensive to implement.
• Reliability: Baseband signals are reliable for short-distance communication.

However, baseband signals also have some disadvantages, including:

• Bandwidth: Baseband signals require a lot of bandwidth.
• Distance: Baseband signals cannot be transmitted over long distances without distortion.

Baseband signals are used in a variety of applications, including:

• Computer networks: Baseband signals are used in computer networks to connect devices such as computers, printers, and servers.
• Telecommunications: Baseband signals are used in telecommunications networks to transmit voice and data signals over copper wires or fiber optic cables.
• Consumer electronics: Baseband signals are used in consumer electronics devices such as TVs, stereos, and computers.

Here are some examples of how baseband signals are used in different settings:

• In a home network, baseband signals are used to connect devices such as computers, printers, and smart TVs to each other.
• In a business network, baseband signals are used to connect devices such as computers, servers, and printers to each other.
• In a telecommunications network, baseband signals are used to transmit voice and data signals over copper wires or fiber optic cables.
• In a consumer electronics device, such as a TV or stereo, baseband signals are used to transmit audio and video signals between the different components of the device.

NETWORKING MODELS

OSI MODEL

The Open Systems Interconnection (OSI) model is a conceptual model that describes how data is communicated over a network. It was developed by the International Organization for Standardization (ISO) in the 1970s and is still widely used today.

The OSI model is divided into seven layers, each of which has a specific function. The layers are:

1. Physical layer: The physical layer is responsible for the physical transmission of data over a network medium, such as copper wires, fiber optic cables, or radio waves.
2. Data link layer: The data link layer is responsible for framing data into packets and for error detection and correction.
3. Network layer: The network layer is responsible for routing packets from the source device to the destination device.
4. Transport layer: The transport layer is responsible for providing reliable end-to-end communication between the source device and the destination device.
5. Session layer: The session layer is responsible for establishing, managing, and terminating sessions between two devices.
6. Presentation layer: The presentation layer is responsible for transforming data into a format that can be understood by the destination device.
7. Application layer: The application layer is responsible for providing network services to applications, such as email, file transfer, and web browsing.

The OSI model is a useful tool for understanding how networks work and for troubleshooting network problems. It is also used to design and implement new network technologies.

Here is an example of how the OSI model works:

1. A user types a message into an email application.
2. The application layer of the OSI model on the user's computer converts the message into a format that can be transmitted over the network.
3. The transport layer of the OSI model on the user's computer segments the message into packets and assigns each packet a sequence number.
4. The network layer of the OSI model on the user's computer routes the packets to the destination email server.
5. The transport layer of the OSI model on the destination email server reassembles the packets into the original message.
6. The application layer of the OSI model on the destination email server delivers the message to the recipient's inbox.

TCP/IP MODEL

The Transmission Control Protocol/Internet Protocol (TCP/IP) model is a suite of protocols that are used to communicate over the internet. It is the most widely used network model in the world.

The TCP/IP model is divided into four layers, each of which has a specific function. The layers are:

• Link layer: The link layer is responsible for transmitting data over a physical network medium, such as copper wires, fiber optic cables, or radio waves.
• Internet layer: The internet layer is responsible for routing packets from the source device to the destination device.
• Transport layer: The transport layer provides reliable end-to-end communication between the source device and the destination device.
• Application layer: The application layer provides network services to applications, such as email, file transfer, and web browsing.

The TCP/IP model is simpler than the OSI model, but it is still a powerful tool for understanding how networks work and for troubleshooting network problems. It is also used to design and implement new network technologies.

Here is an example of how the TCP/IP model works:

• A user types a message into a web browser.
• The application layer of the TCP/IP model on the user's computer converts the message into a format that can be transmitted over the internet.
• The transport layer of the TCP/IP model on the user's computer segments the message into packets and assigns each packet a sequence number.
• The internet layer of the TCP/IP model on the user's computer routes the packets to the destination web server.
• The transport layer of the TCP/IP model on the destination web server reassembles the packets into the original message.
• The application layer of the TCP/IP model on the destination web server delivers the message to the web browser.

The TCP/IP model is an essential part of the modern internet. It allows us to communicate with each other and to access information and resources from all over the world.

Here are some of the key benefits of the TCP/IP model:

• Simple: The TCP/IP model is simpler than other network models, such as the OSI model. This makes it easier to understand and implement.
• Robust: The TCP/IP model is a very robust network model. It is designed to withstand errors and to continue operating even when there are problems with the network.
• Flexible: The TCP/IP model is a very flexible network model. It can be used to support a wide variety of network technologies and applications.

Network Access Layer

• A network layer is the lowest layer of the TCP/IP model.
• A network layer is the combination of the Physical layer and Data Link layer defined in the OSI reference model.
• It defines how the data should be sent physically through the network.
• This layer is mainly responsible for the transmission of the data between two devices on the same network.
• The functions carried out by this layer are encapsulating the IP datagram into frames transmitted by the network and mapping of IP addresses into physical addresses.
• The protocols used by this layer are ethernet, token ring, FDDI, X.25, frame relay.

Internet Layer

• An internet layer is the second layer of the TCP/IP model.
• An internet layer is also known as the network layer.
• The main responsibility of the internet layer is to send the packets from any network, and they arrive at the destination irrespective of the route they take.

Following are the protocols used in this layer are:

• IP Protocol: IP protocol is used in this layer, and it is the most significant part of the entire TCP/IP suite.
• Following are the responsibilities of this protocol:
• IP Addressing: This protocol implements logical host addresses known as IP addresses. The IP addresses are used by the internet and higher layers to identify the device and to provide internetwork routing.
• Host-to-host communication: It determines the path through which the data is to be transmitted.
• Data Encapsulation and Formatting: An IP protocol accepts the data from the transport layer protocol. An IP protocol ensures that the data is sent and received securely, it encapsulates the data into message known as IP datagram.
• Fragmentation and Reassembly: The limit imposed on the size of the IP datagram by data link layer protocol is known as Maximum Transmission unit (MTU). If the size of IP datagram is greater than the MTU unit, then the IP protocol splits the datagram into smaller units so that they can travel over the local network. Fragmentation can be done by the sender or intermediate router. At the receiver side, all the fragments are reassembled to form an original message.
• Routing: When IP datagram is sent over the same local network such as LAN, MAN, WAN, it is known as direct delivery. When source and destination are on the distant network, then the IP datagram is sent indirectly. This can be accomplished by routing the IP datagram through various devices such as routers.

ARP Protocol

• ARP stands for Address Resolution Protocol.
• ARP is a network layer protocol which is used to find the physical address from the IP address.
• The two terms are mainly associated with the ARP Protocol:
• ARP request: When a sender wants to know the physical address of the device, it broadcasts the ARP request to the network.
• ARP reply: Every device attached to the network will accept the ARP request and process the request, but only recipient recognize the IP address and sends back its physical address in the form of ARP reply. The recipient adds the physical address both to its cache memory and to the datagram header.

ICMP Protocol

• ICMP stands for Internet Control Message Protocol.
• It is a mechanism used by the hosts or routers to send notifications regarding datagram problems back to the sender.
• A datagram travels from router-to-router until it reaches its destination. If a router is unable to route the data because of some unusual conditions such as disabled links, a device is on fire or network congestion, then the ICMP protocol is used to inform the sender that the datagram is undeliverable.
• An ICMP protocol mainly uses two terms:
• ICMP Test: ICMP Test is used to test whether the destination is reachable or not.
• ICMP Reply: ICMP Reply is used to check whether the destination device is responding or not.
• The core responsibility of the ICMP protocol is to report the problems, not correct them. The responsibility of the correction lies with the sender.
• ICMP can send the messages only to the source, but not to the intermediate routers because the IP datagram carries the addresses of the source and destination but not of the router that it is passed to.

Transport Layer

The transport layer is responsible for the reliability, flow control, and correction of data which is being sent over the network.

The two protocols used in the transport layer are User Datagram protocol and Transmission control protocol.

• User Datagram Protocol (UDP)
• It provides connectionless service and end-to-end delivery of transmission.
• It is an unreliable protocol as it discovers the errors but not specify the error.
• User Datagram Protocol discovers the error, and ICMP protocol reports the error to the sender that user datagram has been damaged.
• UDP consists of the following fields:
• Source port address: The source port address is the address of the application program that has created the message.
• Destination port address: The destination port address is the address of the application program that receives the message.
• Total length: It defines the total number of bytes of the user datagram in bytes.
• Checksum: The checksum is a 16-bit field used in error detection.
• UDP does not specify which packet is lost. UDP contains only checksum; it does not contain any ID of a data segment.
• Transmission Control Protocol (TCP)
• It provides a full transport layer services to applications.
• It creates a virtual circuit between the sender and receiver, and it is active for the duration of the transmission.
• TCP is a reliable protocol as it detects the error and retransmits the damaged frames. Therefore, it ensures all the segments must be received and acknowledged before the transmission is considered to be completed and a virtual circuit is discarded.
• At the sending end, TCP divides the whole message into smaller units known as segment, and each segment contains a sequence number which is required for reordering the frames to form an original message.
• At the receiving end, TCP collects all the segments and reorders them based on sequence numbers.

Application Layer

• An application layer is the topmost layer in the TCP/IP model.
• It is responsible for handling high-level protocols, issues of representation.
• This layer allows the user to interact with the application.
• When one application layer protocol wants to communicate with another application layer, it forwards its data to the transport layer.
• There is an ambiguity occurs in the application layer. Every application cannot be placed inside the application layer except those who interact with the communication system. For example: text editor cannot be considered in application layer while web browser using HTTP protocol to interact with the network where HTTP protocol is an application layer protocol.

Following are the main protocols used in the application layer:

• HTTP: HTTP stands for Hypertext transfer protocol. This protocol allows us to access the data over the world wide web. It transfers the data in the form of plain text, audio, video. It is known as a Hypertext transfer protocol as it has the efficiency to use in a hypertext environment where there are rapid jumps from one document to another.
• SNMP: SNMP stands for Simple Network Management Protocol. It is a framework used for managing the devices on the internet by using the TCP/IP protocol suite.
• SMTP: SMTP stands for Simple mail transfer protocol. The TCP/IP protocol that supports the e-mail is known as a Simple mail transfer protocol. This protocol is used to send the data to another e-mail address.
• DNS: DNS stands for Domain Name System. An IP address is used to identify the connection of a host to the internet uniquely. But, people prefer to use the names instead of addresses. Therefore, the system that maps the name to the address is known as Domain Name System.
• TELNET: It is an abbreviation for Terminal Network. It establishes the connection between the local computer and remote computer in such a way that the local terminal appears to be a terminal at the remote system.
• FTP: FTP stands for File Transfer Protocol. FTP is a standard internet protocol used for transmitting the files from one computer to another computer.

NETWORK PORTS AND PROTOCOLS

Network ports and protocols are essential for communication between devices on a network. A port is a communication endpoint that is used to identify a specific process or application on a device. A protocol is a set of rules that governs how data is transmitted over a network. Here are some common network ports and protocols:

1. Connection-oriented versus Connectionless Protocols: Connection-oriented protocols, such as TCP, establish a dedicated connection between two devices before data transmission begins. Connectionless protocols, such as UDP, do not establish a dedicated connection before data transmission begins.
2. IP: The Internet Protocol (IP) is a connectionless protocol that is responsible for routing data packets between devices on a network.
3. TCP: The Transmission Control Protocol (TCP) is a connection-oriented protocol that provides reliable, ordered, and error-checked delivery of data between devices on a network.
4. UDP: The User Datagram Protocol (UDP) is a connectionless protocol that provides fast, unreliable, and unordered delivery of data between devices on a network.
5. FTP: The File Transfer Protocol (FTP) is a protocol used for transferring files between devices on a network. It uses TCP for reliable data transfer.
6. SFTP: The Secure File Transfer Protocol (SFTP) is a protocol used for transferring files securely between devices on a network. It uses SSH for secure data transfer.
7. TFTP: The Trivial File Transfer Protocol (TFTP) is a simple protocol used for transferring small files between devices on a network. It uses UDP for fast data transfer.
8. SMTP: The Simple Mail Transfer Protocol (SMTP) is a protocol used for sending email between devices on a network.
9. HTTP: The Hypertext Transfer Protocol (HTTP) is a protocol used for transferring data between web servers and web clients.
10. HTTPS: The Hypertext Transfer Protocol Secure (HTTPS) is a protocol used for transferring data securely between web servers and web clients.
11. POP: The Post Office Protocol (POP) is a protocol used for retrieving email from a mail server.
12. IMAP: The Internet Message Access Protocol (IMAP) is a protocol used for retrieving email from a mail server.
13. Telnet: The Telnet protocol is a protocol used for remote access to devices on a network.
14. Secure Shell (SSH): The Secure Shell protocol is a protocol used for secure remote access to devices on a network.
15. ICMP: The Internet Control Message Protocol (ICMP) is a protocol used for error reporting and diagnostic purposes on a network.
16. NTP: The Network Time Protocol (NTP) is a protocol used for synchronizing the clocks of devices on a network.
17. LDAP: The Lightweight Directory Access Protocol (LDAP) is a protocol used for accessing and managing directory information on a network.
18. SNMP: The Simple Network Management Protocol (SNMP) is a protocol used for managing and monitoring network devices.
19. SIP: The Session Initiation Protocol (SIP) is a protocol used for establishing and managing multimedia sessions on a network.
20. RDP: The Remote Desktop Protocol (RDP) is a protocol used for remote access to devices on a network.
21. SMB: The Server Message Block (SMB) protocol is a protocol used for file and printer sharing between devices on a network.
22. ARP and RARP: The Address Resolution Protocol (ARP) and Reverse Address Resolution Protocol (RARP) are protocols used for mapping IP addresses to MAC addresses and vice versa.

DISCUSS INTERNET ACCESS TECHNOLOGIES

Internet access technologies refer to the different methods used to connect to the internet. Here are some common internet access technologies:

1. DSL: Digital Subscriber Line (DSL) is a family of technologies used to provide internet connectivity over telephone lines. DSL provides high-speed internet access and is widely available in urban and suburban areas.
2. Cable Broadband: Cable broadband is a type of internet access that uses the same coaxial cable that delivers cable television. Cable broadband provides high-speed internet access and is widely available in urban and suburban areas.
3. Dial-up: Dial-up is a type of internet access that uses a modem and a phone call placed over the public switched telephone network (PSTN) to connect to a pool of modems operated by an ISP. Dial-up is a slow and outdated technology and is rarely used today.
4. Public Switched Telephone Network: The Public Switched Telephone Network (PSTN) is a global network of public telephone networks that provides circuit-switched telephone communication.
5. Satellite Internet Access: Satellite internet access is a type of internet access that uses a satellite dish to connect to the internet. It is commonly used in rural or remote areas where other types of internet access are not available.
6. Wireless Internet Access: Wireless internet access is a type of internet access that uses wireless networks to connect to the internet. It is commonly used in urban areas and is available through Wi-Fi hotspots and cellular networks.

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