Networking Presentation PDF

1. What are Data Communications and Computer Networks? Data Communications: Data communication is the process of sending and receiving information between two or more devices. This can be done through cables, wireless signals, or other forms of connections. Computer Networks: A computer networ...

1. What are Data Communications and Computer Networks? Data Communications: Data communication is the process of sending and receiving information between two or more devices. This can be done through cables, wireless signals, or other forms of connections. Computer Networks: A computer network is a group of computers and devices connected together to share information and resources like printers, files, or the internet. This connection can be within a small office or across different locations worldwide. 2. Advantages and Disadvantages of Using Computer Networks Advantages of using computer networks 1. Sharing Resources: - People can share things like printers, files, and programs, so the company doesn't need to buy these for everyone separately. - Example: In an office, multiple employees can use the same printer connected to the network, so the company doesn’t need to buy a printer for every person. 2. Better Communication: - Networks make it easy for people to talk and work together using emails, messages, and video calls. - Example: A team working on a project can use a messaging app and video calls to discuss their work in real-time, making collaboration easier and faster. 3. Centralized Data Storage: - All important information can be kept in one place, making it easier to manage, back up, and keep safe. - Example: A company's financial records are stored on a central server. This means that all employees can access the same up-to-date data and it’s easier to back up and protect. 4. Remote Work: - Employees can connect to the network from home or anywhere else, allowing them to work flexibly. - Example: An employee can log into the company's network from home using a VPN (Virtual Private Network) to access files and work just as if they were in the office. 5. Saving Money: - By sharing resources and having everything in one place, companies can save money on equipment and software. Example: A company saves money by using a shared database for all departments instead of buying separate software licenses for each department. 6. Easy to Grow: - Networks can be expanded as the business grows, adding new users and devices without much hassle.  - Example: A small business can add more computers and users to their network as they hire more staff, without needing to completely overhaul their system. 7. Data Backup: - Networks can automatically save copies of important data, making it easier to recover if something goes wrong. - Example: A network can be set up to automatically back up important files to a cloud service every night, so if a computer crashes, the data can be easily recovered. 8. Security: - Networks can be protected with passwords and other security measures to keep important information safe from hackers. - Example: The company uses strong passwords and encryption to protect sensitive information on their network, helping to prevent unauthorized access and keep data safe from hackers Disadvantages of using computer networks 1. Security Risks: - Networks can be targeted by hackers, viruses, and other threats, so strong security is needed to keep information safe. - Example: A company's network gets hacked, and sensitive customer information, like credit card numbers, is stolen. This could lead to financial loss and damage to the company's reputation. 2. Complex Setup: - Setting up and maintaining a network can be complicated and might require special knowledge and skills. - Example: A small business tries to set up its first network but struggles because the employees don’t have the technical knowledge required. They have to hire an IT specialist, which costs extra money. 3. Costs: - Building a network and keeping it running can be expensive, especially for large organizations. - Example: A large organization spends a significant amount of money on servers, networking equipment, and IT staff to set up and maintain a secure network. The ongoing costs also include software licenses and security updates. 4. Dependence on the Network: - If the network goes down or has problems, it can stop work and cause delays, as many tasks rely on the network. - Example: An e-commerce company’s network goes down due to a technical problem. As a result, customers can’t make purchases, and the company loses sales until the network is restored. 5. Privacy Concerns: - With many users on a network, there can be concerns about who can access certain information, so careful management is needed. - Example: In a large organization, an employee accidentally accesses confidential HR files because the network wasn’t properly secured to restrict access to sensitive data. 6. Technical Issues: - Networks can experience problems like slow speeds, connection issues, or hardware failures, which can disrupt work. - Example: A school’s network frequently experiences slow speeds, making it difficult for students to access online learning resources and for teachers to upload assignments. 7. Maintenance: - Regular maintenance and updates are needed to keep the network secure and running smoothly, which can take time and effort. - Example: A hospital’s network needs regular updates to its software and security systems. If these updates aren’t done on time, it could lead to vulnerabilities in patient data security. Analog and Digital Signals Analog Signals: - Definition: Analog signals are smooth and continuous, changing gradually. They can have any value in a range. - Examples: - Radio Waves: Traditional radio broadcasts (AM and FM) use analog signals, which vary continuously to carry sound. - Old Thermometers: A mercury thermometer shows temperature with a smooth movement of mercury, representing temperature in an analog way. Digital Signals: - Definition: Digital signals are made up of separate, distinct values, usually 0s and 1s. They jump between specific levels rather than changing smoothly. - Examples: - Computer Data: Information sent over the internet or stored on a computer is in digital form, using 0s and 1s. - Digital Clocks: Digital clocks use separate numbers to show the time, jumping from one number to the next rather than moving smoothly. Applications of computer networks: 1. File Sharing: - Example: Employees in an office can share and access documents from a central server, making it easy to collaborate on projects. 2. Email and Messaging: - Example: Teams use email and instant messaging to communicate quickly and effectively, even if they are working in different locations. 3. Internet Access: - Example: A network allows all computers in a school to connect to the internet, so students and teachers can access online resources and websites. 4. Remote Work: - Example: Employees can work from home by connecting to the company’s network using a Virtual Private Network (VPN), accessing files and applications as if they were in the office. 5. Enterprise Resource Planning (ERP): - Example: Large companies use ERP systems to manage business processes like accounting, inventory, and human resources from a centralized network. 6. Customer Relationship Management (CRM): - Example: Businesses use CRM systems to track and manage interactions with customers, helping improve sales and customer service. 7. Streaming Services:  - Example: Services like Netflix and Spotify deliver movies, TV shows, and music over the internet to users’ devices via a network. 8. Online Gaming: - Example: Multiplayer online games let players from around the world connect and play together over the internet. Authored by Nelclash Discuss network types Network is a group of two or more computers or devices connected together to share resources, such as files, data or internet access and to communicate with each other. This can be done using wired or wireless connections. Local Area Network (LAN) - A LAN is a network that connects computers and devices in a limited geographical area, such as a home, office, or campus. - Commonly used for sharing resources like printers and files. - High-speed connectivity and low cost make LANs popular in small-scale setups. Wireless Local Area Network (WLAN) - A WLAN uses wireless technology to connect devices within a limited area. - Provides flexibility and mobility as devices can connect without physical cables. - Common in homes, cafes, and offices for seamless connectivity. Wide Area Network (WAN) - A WAN covers a wide geographical area, connecting multiple LANs and other networks. - Utilizes public and private networks to establish long-distance communication. - Essential for connecting offices across different cities or countries. Metropolitan Area Network (MAN) - A MAN covers a larger geographical area than a LAN but smaller than a WAN, typically within a city. - Offers high-speed connectivity for organizations within the city limits. - Supports businesses, educational institutions, and government agencies. Campus Area Network (CAN) - A CAN interconnects multiple LANs within a university campus, corporate campus, or industrial complex. - Facilitates efficient communication and resource sharing among different departments. - Ensures seamless connectivity for diverse campus activities. Personal Area Network (PAN) - A PAN is a network for connecting personal devices within a short range, like smartphones, laptops, and wearable gadgets. - Enables data sharing and communication among personal devices. - Often used for Bluetooth and infrared connections. Topologies Network topology is the way different parts of a computer network are connected to each other. It shows how devices like computers, printers, and servers are linked, either using wires or wirelessly. Think of it like the layout of streets in a neighborhood, where different roads (connections) join houses (devices). The most common types are: 1. Bus Topology In a bus topology, all devices (computers, printers, etc.) are connected to a single central cable called the "bus." Data travels along this cable, and each device listens for messages addressed to it. Advantages: - Cost-effective: Requires less cable compared to other topologies, making it cheaper to set up. - Simple setup: Easy to install and extend by adding more devices to the main cable. Disadvantages: - Single point of failure: If the main cable fails, the entire network goes down. - Slow with heavy traffic: Performance decreases as more devices are added since all devices share the same cable. - Troubleshooting difficulties: It can be hard to identify the problem when the network goes down. Example: Early Ethernet networks used bus topology, especially in small offices. 2. Ring Topology In a ring topology, each device is connected to two other devices, forming a circular loop. Data travels in one direction (or sometimes two) around the ring, passing through each device until it reaches its destination. Advantages: - Equal access: Every device has equal access to the network, so no single device can hog bandwidth. - Easy to manage: Easier to locate the source of a problem compared to bus topology since the data follows a defined path. Disadvantages: - Single point of failure: If one device or connection fails, it can take down the entire network (unless dual rings are used). - Limited scalability: Hard to add new devices without interrupting the network. Example: Fiber Distributed Data Interface (FDDI) and Token Ring networks used this topology, often in older corporate networks. 3. Star Topology In a star topology, all devices are connected to a central hub or switch. The hub acts as the main point through which all communication between devices passes. Advantages: - Centralized control: Easy to manage, troubleshoot, and add or remove devices. - If one device fails, the network stays up: Since each device connects to the hub independently, the failure of one device won’t affect the entire network. - Faster performance: Each device has its own direct line to the central hub, reducing the risk of network congestion. Disadvantages: - Central point of failure: If the hub or switch goes down, the entire network fails. - Higher cost: Requires more cable and hardware (the central hub/switch) than a bus topology. Example: Most modern Ethernet networks in offices and homes use star topology, where devices connect to a central router or switch. Mesh Topology Mesh Topology is a type of network set up that every node is connected to every other node, its either directly or indirectly. Mesh Topology looked more complicated than other topologies we had covered. So this setup creates many different paths for data to travel from one device to another device. Commonly used in Wi-fi networks in large buildings or areas. peer-to-peer networks Advantages Reliable: network keeps working even if some parts fail. No single point of failure: the network doesn’t depend on a single connection Secure: direct connections make it hard for outsiders to intercept data. Disadvantages Expensive: requires more cables and hardware, increasing setup and maintenance costs. Difficult To Manage: managing many connections can be challenging. Hard to Expand: adding new devices can increase complexity. Hydrid Topology Advantages of Hybrid Topology: 1. Flexible: Combines strengths of different topologies to suit various needs. 2. Scalable: Can be expanded easily by adding new sub-topologies. 3. Reliable: Fault tolerance depends on the specific topologies used. Disadvantages of Hybrid Topology: 1. Complexity: More complex to design and manage due to multiple topologies. 2. Cost: Can be more expensive due to the combination of different systems and equipment. 3. Troubleshooting: Issues can be harder to diagnose due to the hybrid nature of the network. 1.3 Identify appropriate networking equipment Data Transmission Media Are physical pathways or channels through which data is transmitted from one device to another. They can be classified into two main categories: Wired (Guided) Media Wireless (Unguided) Media Unshielded Twisted Pair (UTP) - Cables with pairs of wires twisted together without extra shielding.  Advantages - Cheap: Less expensive than other cables. - Easy to Install: Flexible and lightweight. - Good for Short Distances: Works well in homes and offices. Disadvantages - Interference: Easily affected by electrical noise. - Lower Speed: Not as fast as some other cables. - Limited Range: Works best up to 100 meters. Common Uses - Home and office networks (Ethernet) - Telephone lines Shielded Twisted Pair (STP) - Similar to UTP but with a metal shield around the wires for protection. Advantages - Less Interference: The shield blocks electrical noise. - Better Speed: Can handle higher data rates. Disadvantages - More Expensive: Costs more due to the extra shielding. - Harder to Install: Less flexible and requires grounding. Common Uses - Industrial areas with lots of electrical noise - Data centers that need higher speeds A Coaxial Cable, or coax cable, is a type of electrical cable used to transmit data, video, and voice communications. Structure of Coaxial Cable 1. Center Conductor: A single copper wire that carries the signal. 2. Insulating Layer: Surrounds the center conductor to prevent signal loss. 3. Metallic Shield: A mesh or foil layer that protects against electromagnetic interference (EMI). 4. Outer Jacket: An external plastic cover that protects the cable. Advantages - Good Shielding: The metallic shield reduces interference, providing a clearer signal. - High Bandwidth: Can carry a large amount of data, making it suitable for TV and internet. - Durable: Resistant to physical damage and can be used over long distances without significant signal loss. Disadvantages - Less Flexible: Thicker and less flexible compared to other cables like twisted pair. - Installation Cost: More expensive to install, especially for large networks. - Limited Upgrade: Harder to upgrade than some other types of cables, such as fiber optic. Common Uses - Cable TV: Used to transmit cable television signals. - Internet: Provides broadband internet connections. - Satellite Communication: Used in satellite dish connections and antenna systems. A Fibre-Optic cable is a type of network cable that uses thin strands of glass or plastic fibers to transmit data as light signals. Structure of Fiber-Optic Cable 1. Core: The thin glass or plastic center where light signals travel. 2. Cladding: A layer surrounding the core that reflects light back into the core to prevent signal loss. 3. Buffer Coating: Protects the fiber from damage and moisture. Advantages - High Speed: Can transmit data at very high speeds, much faster than traditional copper cables. - Long Distance: Can carry signals over long distances without significant loss. - No Interference: Immune to electromagnetic interference, providing a clear signal. Disadvantages - Cost: More expensive to install and maintain than other cables. - Fragility: The glass fibers are delicate and can break if mishandled. - Complex Installation: Requires specialized equipment and skills to install. Common Uses - Internet and cable TV services - Long-distance telecommunications - Data centers and high-speed networks Wireless media transmits data using electromagnetic waves without physical cables. Types of Wireless Media 1. Radio Waves: Used in Wi-Fi, Bluetooth, and radio broadcasting. Covers short to long distances. 2. Microwaves: Used in satellite communication and cellular networks. Requires line-of-sight. 3. Infrared (IR): Short-range communication, used in remote controls and wireless peripherals. 4. Satellite: Uses satellites for global coverage, like GPS and satellite TV. Advantages - Enables mobility - Easy to set up - Covers large areas Disadvantages - Prone to interference - Security risks - Limited data transfer rates Connectivity devices In computer networking, connectivity devices are hardware components that facilitate the communication and interconnection of various network devices. Firewall A firewall is a security tool that controls the data coming into and out of a network to keep it safe. Advantages: 1. Security: Protects against hackers and malicious traffic. 2. Control: Lets you decide which services and websites can be accessed. 3. Monitoring: Tracks and records network activity. Disadvantages: 1. Complex Setup: Can be tricky to configure correctly. 2. Performance: Might slow down network speed. 3. Blocking Issues: Could block legitimate traffic by mistake. Example: A company uses a firewall to block employees from accessing social media sites while allowing access to work-related websites. What router A router is a device that connects different networks, like a home network to the internet, and directs data between them. Advantages: 1. Connects multiple devices to the internet. 2. Manages and directs data efficiently. 3. Provides basic security features. Disadvantages: 1. Can be complex to set up. 2. Limited wireless range. 3. Can slow down with too many devices. Example: In a home, a router connects your phone and laptop to the internet, letting you browse and stream content. What is Switch? A switch is a network device that connects multiple devices within the same network and directs data to the correct device using MAC addresses. Advantages: 1. Efficient data transfer to specific devices. 2. Improves network performance. 3. Supports many devices. Disadvantages: 1. More expensive than a hub. 2. Complex to set up for large networks. 3. Doesn’t control or prioritize traffic. Example: In an office, a switch connects computers and printers, allowing them to share files and resources efficiently. Hub A hub is a basic network device that connects multiple devices in a local area network (LAN). It broadcasts data to all connected devices, regardless of the intended recipient. Advantages: 1. Simple to Use: Easy to set up with no complex configuration. 2. Cost-Effective: Generally cheaper than switches and routers. 3. Connects Multiple Devices: Allows several devices to be connected to the network. Disadvantages: 1. Inefficient Data Transfer: Sends data to all devices, leading to network congestion. 2. Security Risk: Increases the risk of data interception since data is broadcast to all devices. 3. Limited Performance: Slower network speeds due to data collisions. Example: In a small home network, a hub connects a few computers, allowing them to communicate. However, it sends all data to every device, which can slow down the network as more devices are added. Bridge A bridge is a network device that connects and filters traffic between two or more network segments, improving communication and reducing traffic on each segment. Advantages: 1. Reduces Network Traffic: Filters data and only forwards necessary traffic. 2. Extends Networks: Connects different network segments, allowing them to work as one. 3. Improves Performance: Decreases congestion by dividing large networks into smaller segments. Disadvantages: 1. Limited Scope: Only connects similar network types (e.g., Ethernet to Ethernet). 2. Slower Data Processing: Can be slower than switches in handling data. 3. No Traffic Prioritization: Does not prioritize or manage network traffic like routers do. Example: In an office, a bridge connects two separate departments' networks, allowing them to share resources while reducing unnecessary traffic between the two segments. Modem A modem is a device that converts digital data from a computer into analog signals for transmission over phone lines, cable, or satellite, and vice versa, enabling internet access. Advantages: 1. Internet Access: Allows devices to connect to the internet. 2. Compatibility: Works with various types of internet connections (DSL, cable, fiber). 3. Simple Setup: Easy to install and configure for basic internet access. Disadvantages: 1. Speed Limits: Limited by the type and speed of the internet connection. 2. Security Risks: Basic modems lack advanced security features, making them vulnerable to attacks. 3. Single Device Focus: Often only provides internet access without additional network management features. Example: In a home network, a modem connects to the internet service provider (ISP) and provides internet access to devices like computers and smart TVs. It converts the data for use over the internet connection. Wireless Access Point A wireless access point (WAP) is a device that allows wireless devices to connect to a wired network using Wi-Fi. Advantages: 1. Wireless Connectivity: Enables devices to connect to the network without cables. 2. Expands Network Coverage: Increases Wi-Fi coverage in large areas. 3. Supports Multiple Devices: Allows many devices to connect simultaneously. Disadvantages: 1. Security Risks: Can be vulnerable to unauthorized access if not properly secured. 2. Signal Interference: Susceptible to interference from other electronic devices or physical obstructions. 3. Limited Range: Coverage area is limited and may require multiple access points for larger spaces. Example: In an office, a WAP is used to provide Wi-Fi access to employees' laptops and smartphones, allowing them to connect to the network without using Ethernet cables. Media Converter A media converter is a device that converts data between different types of network media, such as from fiber optic to copper Ethernet. Advantages: 1. Compatibility: Connects different types of network cables, like fiber to Ethernet. 2. Cost-Effective: Allows integration of older network equipment with newer technology. 3. Flexibility: Supports various media types and network standards. Disadvantages: 1. Limited Functionality: Only converts between media types; does not manage or secure traffic. 2. Potential Bottleneck: Can introduce latency or reduce network performance if not properly configured. 3. Additional Equipment: Requires separate power and management compared to integrated solutions. Example: In an office, a media converter connects a fiber optic network to an Ethernet switch, enabling devices on the Ethernet network to communicate over the fiber optic infrastructure. Wireless Range Extender A wireless range extender (or Wi-Fi extender) is a device that amplifies and extends the coverage area of a wireless network. Advantages: 1. Increases Coverage: Expands the Wi-Fi signal to areas with weak or no coverage. 2. Easy Setup: Typically easy to install and configure. 3. Improves Connectivity: Enhances Wi-Fi signal strength in remote areas of a home or office. Disadvantages: 1. Reduced Speed: Can decrease network speed due to signal repetition. 2. Limited Range: Effectiveness depends on the distance from the router and obstacles. 3. Potential Interference: May introduce interference or create additional network congestion. Example: In a large house, a wireless range extender is placed in a location between the router and a distant room to boost the Wi-Fi signal, ensuring a stable internet connection in that room. VoIP Endpoint A VoIP endpoint is a device or application used to make and receive voice calls over the Internet using Voice over IP (VoIP) technology. Advantages: 1. Cost-Effective: Typically cheaper than traditional phone systems, especially for long-distance calls. 2. Flexibility: Allows calls from various devices, including smartphones, computers, and dedicated VoIP phones. 3. Feature-Rich: Often includes additional features like video calls, messaging, and call forwarding. Disadvantages: 1. Internet Dependency: Requires a stable internet connection for quality calls. 2. Quality Issues: Call quality can vary based on network conditions and bandwidth. 3. Security Risks: Susceptible to cyber threats like eavesdropping if not properly secured. Example: Using a VoIP endpoint like a smartphone app, a person can make voice calls over the internet to others using the same app or a VoIP phone system, rather than relying on a traditional phone line. Network Operating System A Network Operating System (NOS) is software that manages and controls network resources, including hardware and software, and facilitates communication between networked devices. Advantages: 1. Centralized Management: Simplifies management of network resources and user access. 2. Improved Security: Provides tools for securing network data and user authentication. 3. Resource Sharing: Enables sharing of files, printers, and other resources across the network. Disadvantages: 1. Complex Setup: Can be complex to install and configure, requiring specialized knowledge. 2. Cost: May involve significant costs for licensing and maintenance. 3. Single Point of Failure: Centralized management can create vulnerabilities if the NOS experiences issues. Example: Microsoft Windows Server is a common NOS used in businesses to manage network resources, user accounts, and security while enabling file sharing and network communication. Explain data transmission modes Broadband is a high-capacity method of transmitting large amounts of data over the internet or other communication networks. It allows you to use the internet, watch videos, or make phone calls at the same time, without slowing down. It works by splitting a connection into many parts so multiple things can happen at once Examples; Home internet (like Wi-Fi) Cable TV Mobile data (4G/5G) Baseband is a way of sending one signal or piece of data at a time over a network. It uses the full capacity of the connection for just that one signal. This is common in smaller networks where only one device is sending data at a time Example; Ethernet cables used in local networks (like in office or home) work with baseband. Feature Baseband Broadband Signals Sends one signal at a time Sends multiple signals at once Type of Signal Usually digital Can be digital or analogue Range Short-distance like inside a Long-distance (across cities or building regions) How it Works Uses the full bandwidth for Splits bandwidth into smaller one signal parts for each signal Examples Ethernet (computer networks) Cable TV Internet Synchronous transmission is when data is sent between devices at the same time, following a shared clock or timing signal, both sender and receiver are synchronized, so they know exactly when data is sent and received. Example, In synchronous transmission, like a video call, both sides send and receive data in real-time, staying perfectly in sync Asynchronous transmission is when data is sent between devices without needing to be in sync or follow a shared clock. The data can be sent at any time, and each piece of data has start and stop signals so the receiver knows when it begins and ends. Example; Sending a text message is asynchronous because you can send it whenever and the other person can read it later. Feature Synchronous Transmission Asynchronous Transmission Timing Data is sent at the same time Data can be sent at any time Clock Signal Uses a shared clock to sync No shared clock needed devices Data Structure Data is sent in a continuous Data is sent with start and stop stream signals Efficiency Generally, more efficient for Can be less efficient due to continuous data gaps Examples Video calls, real-time chats Emails, text messages In summary synchronous = same time, uses clock Asynchronous = any time, no clock. Simplex transmission is one-way communication method where data can only flow in one direction. In this type of transmission, one device sends data to another, but the receiving device cannot send data back. Example; A TV broadcast is simplex because the signal goes from the station to the viewers, but viewers cannot send information back to the station. Half-duplex transmission is a communication method where data can flow in both directions, but not at the same time. This means that while one device must wait until the transmission is complete before it can send data back. Example; A walkie-talkie is half-duplex because one person speaks while the other listens, and they have to take turns to talk. Full duplex transmission is a communication method where data can flow in both directions simultaneously. This means that both devices can send and receive data at the same time without waiting for the other to finish. Example; A telephone conversation is full duplex because both people can talk and listen at the same time. Feature Simplex Half-duplex Full duplex Data flow direction One-way only Two-way, but not at Two-way, the same time simultaneously Communication TV broadcast Walkie-talkies Telephone Example conversations Efficiency Efficient for one- Can be less efficient Most efficient for way messages due to waiting real-time interaction Device interaction One device sends, Devices take turns Both devices can the other receives to send and receive send and receive at once Summary: Simplex = one way only. Half-duplex = two ways, but not at the same time. Full duplex = two ways at the same time (simultaneously) 1.4 Describe internetworking technologies Internetworking Technologies Internetworking connects different computer networks so they can communicate with each other. This is essential for how the internet works. Key concepts include switching methods and types of networks. 1. Circuit Switching: - A method where a dedicated line is set up between two people for a call. This line stays open for the entire conversation. - Example: Traditional phone calls. - Pros: - Offers a constant connection. - Ensures a steady flow of communication. - Cons: - Can waste resources when no one is talking. - Not efficient for data like browsing the web. 2. Message Switching: - Each message is sent as a whole and stored at each point until it can be sent on. - Example: Old telegraph systems or some email services. - Pros: - Better use of resources since messages can wait to be sent. - No need for a permanent connection. - Cons: - Can take longer since messages are stored and forwarded. - Needs space to hold messages at each point. 3. Packet Switching: - Data is split into smaller packets, which are sent independently over the network. They can take different routes to reach the destination and are reassembled there. - Example: The internet. - Pros: - Efficient because many packets can share the same path. - Can adjust to problems in the network by finding new routes. - Cons: - Can have delays due to packets arriving at different times. - Some packets may be lost, requiring a resend. 4. Narrowband Networks: - Networks with low bandwidth, usually less than 64 kbps, good for simple tasks. - Example: Dial-up internet. - Pros: - Cheaper and easy to set up. - Works for voice calls and light internet use. - Cons: - Slow speeds, not good for streaming videos or heavy data use. 5. Broadband Networks: - High-speed networks that can carry a lot of data at once. - Example: Fiber-optic or cable internet. - Pros: - Fast speeds for streaming, gaming, and large downloads. - Can support many users at the same time. - Cons: - More expensive to install and maintain. - Needs advanced technology and infrastructure. These technologies help ensure that we can communicate easily and quickly across the internet, whether for calls, emails, or streaming videos.  Discuss networking models Introduction of OSI Model The OSI Model (Open Systems Interconnection Model) is a 7-layer framework developed by ISO in 1984 to standardize network communication. It ensures that different systems can communicate, even if they are from different manufacturers, by organizing network functions into specific layers. The OSI model organizes network communication into seven layers, each with a specific function. When data is sent, it starts at the Application Layer, where the user interacts with programs like wed browsers. The Presentation Layer then formats or encrypts the data, while the Session Layer manages the connection between devices. The Transport Layer ensures reliable data transfer by breaking it into smaller segments. The Network Layer determines the best route for the data using IP addresses. The Data Link Layer handles error checking and data transfer between devices on the same network and finally, the Physical Layer transmits the data as electrical signals or radio waves. When receiving data, the process reverses The seven layers are: 1. Physical Layer – Handles the physical connection (cables, signals). 2. Data Link Layer – Manages data transfer between connected devices. 3. Network Layer – Determines the path for data to travel. 4. Transport Layer – Ensures reliable data transfer and error checking. 5. Session Layer – Manages and controls connections between devices. 6. Presentation Layer – Formats and encrypts data for the application layer. 7. Application Layer – Provides network services to user applications. 1. Physical Layer The lowest layer responsible for the physical connection between devices, including cables, signals, and hardware transmission. Advantages: - Provides the hardware to transmit data (cables, signals, etc.). - Ensures data can be sent across physical mediums (wires, fiber optics). Disadvantages: - No control over data integrity or security. - Hardware failures can disrupt communication. 2. Data Link Layer Responsible for error detection, correction, and managing access to the physical network using MAC addresses. Advantages: - Manages error detection and correction at the link level. - Controls access to the physical medium (using MAC addresses). Disadvantages: - Errors not caught here may go unnoticed by upper layers. - Depends on the physical layer for transmission quality. 3. Network Layer Manages data routing and logical addressing (IP addresses) to ensure data reaches the correct destination. Advantages: - Determines the best path for data to travel through the network. - Manages logical addressing (IP addresses) and congestion control. Disadvantages: - Requires efficient routing algorithms, which can be complex in large networks. - Vulnerable to security issues like IP spoofing or route hijacking. 4. Transport Layer Provides reliable data transfer, error recovery, and flow control between devices (using TCP or UDP). Advantages: - Ensures reliable data transfer and manages error recovery (TCP). - Allows a choice between reliable (TCP) or faster but less reliable (UDP) transmission. Disadvantages: - Reliable transfer methods like TCP add overhead, slowing down transmission. - Errors at this layer can disrupt communication between applications. 5. Session Layer Manages sessions or connections between applications, including establishing, maintaining, and terminating them. Advantages: - Manages the start, maintenance, and end of communication sessions. - Allows multiple communication sessions between devices simultaneously. Disadvantages: - Adds complexity to managing sessions, especially long-lasting ones. - Can be unnecessary for simple communications, adding overhead. 6. Presentation Layer Ensures data is formatted correctly for the application layer, handling translation, encryption, and compression. Advantages: - Formats and translates data for compatibility between systems. - Handles encryption and compression to secure and reduce the size of data. Disadvantages: - Data conversion processes (e.g., encryption) can slow down communication. - Redundant for applications that don't require heavy data formatting. 7. Application Layer The top layer that provides services directly to users and applications, like web browsers, email, and file transfer. Advantages: - Provides a direct interface for applications to communicate over the network. - Supports essential services like email, file transfer, and web browsing. Disadvantages: - Vulnerable to security threats like malware and viruses due to user interaction.  - Application performance depends on how well lower layers function. Introduction of TCP/IP Model The TCP/IP Model (Transmission Control Protocol/Internet Protocol Model) is a framework that describes how data is transmitted over the internet. Developed by the U.S. Department of Defense in the 1970s, The TCP/IP model works by breaking data into small packets and sending them across the internet. First, the Application Layer handles user activities like wed browsing or email. Then, the Transport Layer divides the data into packets and ensures they are sent reliably. The Internet Layer adds an IP address to each packet and finds the best route to the destination. Finally, the Network Access Layer physically transmits the data over the network (wired or wireless). When the packets reach the destination, the layers reverse the process to reassemble the data for the user. it consists of four layers: 1. Application Layer: Provides services for applications like web browsing and email. 2. Transport Layer: Ensures reliable data transfer between devices, using protocols like TCP and UDP. 3. Internet Layer: Manages logical addressing and routing of data packets (e.g., IP). 4. Network Access Layer: Handles the physical transmission of data over hardware (e.g., Ethernet). 1. Application Layer Provides network services directly to end-user applications (e.g., web browsers, email clients). Advantages: - Allows user-friendly interfaces and access to network services. - Supports various protocols for different applications (HTTP, FTP, SMTP). Disadvantages: - Vulnerable to security threats like malware and phishing attacks. - Performance can be affected by issues in lower layers. 2. Transport Layer Ensures reliable data transfer between devices, managing error detection and flow control. Advantages: - Provides reliable data transmission (using TCP) or faster transmission (using UDP). - Manages data segmentation and reassembly. Disadvantages: - TCP can introduce overhead and latency due to connection establishment and error- checking processes. - UDP does not guarantee delivery, which can lead to data loss in critical applications. 3. Internet Layer Manages logical addressing and routing of data packets across networks (e.g., using IP addresses). Advantages: - Provides scalability, allowing the connection of multiple networks. - Supports routing and packet forwarding to ensure data reaches its destination. Disadvantages: - Complexity in managing routing tables and protocols, which can lead to performance issues. - Vulnerable to security threats such as IP spoofing and denial-of-service attacks. 4. Network Access Layer Handles the physical transmission of data over the network hardware (e.g., Ethernet). Advantages: - Facilitates communication between devices on the same local network. - Supports various physical media and protocols for data transmission. Disadvantages: - Limited to specific network types (e.g., Ethernet, Wi-Fi) and may not be compatible with others.  - Hardware failures can disrupt the entire network connection. The difference between OSI and TCP/IP Model Feature OSI Model TCP/IP Model Developed by International Organization for U.S Department of Defense Standardization (OSI) Layers 7 Layers 4 Layers Layer Structure Application, Presentation, Application Transport, Session, Transport, Network Internet, Network Access Data Link, Physical Purpose General framework for Designed specifically for the network communication Internet Complexity More complex due to 7 layers Simpler with 4 layers Focus Protocol independence, Practical application for theoretical internet communication Error Handling Each layer can handle errors Mainly managed at the individually Transport layer (TCP) Protocol Examples No specific protocols defined TCP, UDP, IP, HTTP, FTP Connection Types Can support connection- Primarily connection-oriented oriented and connectionless (TCP) and connectionless communication (UDP) Usage Mainly for learning and Widely used in real-world understanding networks networking and the internet. Network Ports and Protocols Network Ports: Ports are virtual channels in a computer's operating system that allow different applications to communicate over a network. Each port is associated with a specific protocol. Connection-Oriented vs. Connectionless Protocols - Connection-Oriented Protocols: - Establish a connection before data transfer (e.g., TCP). - Ensure reliable communication with error checking and data recovery. - Connectionless Protocols: - Send data without establishing a connection (e.g., UDP). - Faster but less reliable; no guarantee of delivery. Key Protocols 1. IP (Internet Protocol): - Responsible for addressing and routing packets of data between devices on a network. 2. TCP (Transmission Control Protocol): - Connection-oriented protocol that ensures reliable data delivery and error correction. 3. UDP (User Datagram Protocol): - Connectionless protocol that sends data quickly without error checking, suitable for streaming. 4. FTP (File Transfer Protocol):  - Used to transfer files between computers over a network. 5. SFTP (Secure File Transfer Protocol): - A secure version of FTP that encrypts data for safety during transfer. 6. TFTP (Trivial File Transfer Protocol): - A simple, connectionless file transfer protocol with no authentication. 7. SMTP (Simple Mail Transfer Protocol): - Used for sending emails between servers. 8. HTTP (Hypertext Transfer Protocol): - The foundation of data communication on the web, used for transferring web pages. 9. HTTPS (Hypertext Transfer Protocol Secure): - A secure version of HTTP that encrypts data for safer web browsing. 10. POP (Post Office Protocol): - Used to retrieve emails from a server; downloads emails for offline access. 11. IMAP (Internet Message Access Protocol): - Allows users to access and manage emails directly on the server, supporting multiple devices. 12. Telnet: - A protocol for remote access to servers and devices, but not secure. 13. Secure Shell (SSH): - A secure protocol for remote access and management of devices. 14. ICMP (Internet Control Message Protocol): - Used for error messages and network diagnostics (e.g., ping). 15. NTP (Network Time Protocol): - Synchronizes clocks of devices over a network. 16. LDAP (Lightweight Directory Access Protocol):  - Used to access and manage directory information services. 17. SNMP (Simple Network Management Protocol): - Used for monitoring and managing network devices. 18. SIP (Session Initiation Protocol): - Used for initiating and managing voice and video calls.