IGCSE ICT Networks Chapter 4 Presentation on Networks.pdf
- 1. WRP: ICT WRP: ICT Electronic Conferencing and Website Authoring Sanavi Naik IGCSE 1
- 2. Agenda Agenda Networks NICS MAC Address IP Address Data Packets Routers Hubs Switches Bridges WiFi & Bluetooth Cloud Computing LAN WAN WLAN Passwords Zero Login and Biometrics Magnetic Stripe Cards Smart Cards Physical Tokens Electronic Tokens Antimalware software Electronic Conferencing Microprocessor controlled Devices
- 3. Networks Networks A computer network is a system of interconnected devices that communicate and share resources using communication protocols.
- 4. Network Network Interface Interface Card (NIC) Card (NIC) A network interface card (NIC) allows a device to connect to a network. The NIC converts binary data into an electrical signal for network access. Most modern computers have NICs integrated into the motherboard. Each NIC is assigned a unique, hardwired media access control (MAC) address during manufacturing. Wireless network interface cards (WNICs) function like NICs but use wireless connectivity. WNICs communicate via microwaves with networks through an antenna. WNICs are typically plugged into a USB port or integrated into the device.
- 5. Data is sent in the form of data packets, which are split into smaller parts. Header contains the sender’s IP, receiver’s IP, sequence number, packet size, and total packet count. The sequence number helps reassemble packets in the correct order at the destination. Routers check the destination IP against their routing table to forward the packet. Data packets pass through multiple routers before reaching the destination, where they are reassembled using the sequence numbers. Network Terms Network Terms Media Access Control Address Uniquely identifies a device on a network. First part indicating the manufacturer and the second part being the device's serial number. Replacing the NIC changes the MAC address. MAC addresses are also called physical addresses and do not change. They are useful for troubleshooting network issues because they provide a reliable way to identify devices. MaC Address MaC Address An IP address identifies a device on a network. It is assigned by the ISP when a device connects to the internet. The IP address changes when you connect to a new network. IPv4 uses 32 bits and is written in four groups of eight bits. IPv6 is the newer version of IP and accounts for the growing number of people using the internet IP ADdress IP ADdress Data Packets Data Packets
- 6. Hubs, Switches and Bridges Hubs, Switches and Bridges A hub connects devices in a LAN and sends data packets to every device. A switch sends data packets only to specific devices using a lookup table and MAC addresses of all the devices A bridge connects 2 LANS together to form a single LAN. They should have the same protocol (communication rules)
- 7. Routers Routers Routers route data packets between networks using IP addresses. Each router has its own IP address to inspect and route incoming packets. Routing tables, stored in the router's RAM, contain IP addresses of devices in the network and neighboring routers. Routers do not store MAC addresses but forward packets to local switches. Switches use MAC addresses to deliver packets to the correct device. Broadband routers combine router and switch functions, storing both MAC and IP addresses to simplify delivery.
- 8. Wi-Fi and Bluetooth Wi-Fi and Bluetooth Both Wi-Fi and Bluetooth use electromagnetic radiation for wireless communication. Bluetooth operates on 79 channels centered around 2.45 GHz, using frequency hopping to avoid interference. Bluetooth is suitable for short-range communication (less than 30 meters), low- bandwidth applications, and non-critical data transmission speeds. Wi-Fi operates on 2.4 GHz and 5 GHz bands, offering faster data transfer, better range, and higher security. Wi-Fi is ideal for full-scale networks, allowing devices to connect to the internet wirelessly up to 100 meters away.
- 9. Advantages: Accessible from anywhere with internet access. No need for physical storage devices. Remote backup for disaster recovery. Large storage capacity. Automatic syncing of files across devices. Ideal for collaboration, with multiple users editing files. Cloud Computing Cloud Computing Data is stored on remote servers with backups (data redundancy) for reliability. Public cloud: Storage provider and client are separate companies. Private cloud: Storage within a dedicated environment, client and provider are the same. Hybrid cloud: Combines both public and private cloud storage. Disadvantages: Security concerns. Reliance on internet speed and stability. Costs for large storage or data transfer. Risk of cloud service failure. Security Concerns: Potential loss of control over data security. Risks include physical security, natural disasters, power cuts, and insider threats. Data loss from hacking or account breaches is a concern.
- 10. LAN, WAN and WLAN LAN, WAN and WLAN LANs connect computers and devices within a single building or nearby area. Advantages: Share hardware (e.g., printers) and software. Easy communication between users on the network. Disadvantages: Viruses can easily spread across the network. Users may face delays for shared devices like printers. Connections to external networks may be slower. Greater risk of unauthorized access compared to standalone computers. If the main server fails, the network may stop working. LOcal Area LOcal Area Network Network WLANs use wireless communication instead of cables. Radio or infrared signals are used for short-distance communication. Access points (APs) connect the WLAN to a wired network. Spread-spectrum radio technology offers a range of 30-50 meters, while infrared has a very limited range of 1-2 meters. Devices access the WLAN using built-in wireless LAN adapters. Wide Area Wide Area Network Network WANs connect computers or networks across large geographic areas, such as cities or countries. WANs are formed by joining multiple LANs using routers. Public networks like telephone lines or satellites are commonly used but can also utilize dedicated or leased lines for cost efficiency and security. WANs consist of end systems and intermediate systems Wireless Wireless local area local area network network
- 11. Passwords Passwords Passwords are used for logging into emails online banking accessing social networking sites and more To keep your password secure: Run antispyware Change password regulary Shouldn’t be easy to crack one capital letter one numerical value one special character (@, # etc.)
- 12. Zero Login & Zero Login & biometrics biometrics Zero login eliminates the need for passwords by using biometrics and behavioral patterns for authentication. Biometrics includes features like fingerprint or face recognition, commonly used in smartphones. Behavioral patterns analyze actions like walking style, typing speed, location, and screen swiping habits. Advantages: Enhanced security (biometrics and behavior are hard to copy) and faster, easier logins. Disadvantages: Concerns about monitoring transparency, logout notifications, and the system's overall protection level.
- 13. Magnetic Stripe Magnetic Stripe Cards Cards Magnetic stripe cards store data using magnetic particles on a plastic film. Data is read by swiping the card through a reader, often used for security or access purposes. Holograms on cards make forgery difficult by displaying changing images or colors. Photographic images on cards prevent unauthorized use by matching the user's identity. Advantages: Easy to use and inexpensive. Can be deactivated remotely if lost or stolen. Multi-purpose functionality (e.g., access, vending). Disadvantages: Less secure than encrypted or biometric methods. Cards wear out with frequent use. Readers can fail to scan on the first attempt.
- 14. Smart Cards Smart Cards Smart contactless cards contain an RFID chip and antenna, allowing them to be read from a distance. They store personal data (e.g., name, security number, date of birth, and PIN). These cards act as security devices for access control. Readers scan the card data, and the user enters a PIN for verification. Access is granted if the scanned data and PIN match.
- 15. Electronic tokens are software-based authentication tools installed on devices like smartphones. How it works: The user installs an electronic token app. The app generates a one-time password (OTP) when prompted by the website. The user enters the OTP and additional authentication (e.g., PIN, touch ID, or face ID). The website server runs the same software, and both the server and app use synchronised clocks to generate matching OTPs. Access is granted once the OTP and additional authentication are verified. Electronic Electronic Tokens Tokens Physical Physical Tokens Tokens Physical tokens are solid objects used for authentication. They generate a one-time password (OTP) after entering a PIN and other details. OTPs are displayed on a small screen and change regularly, valid for less than a minute. Enhances security by requiring the token, a card, and the PIN. Types of tokens: Disconnected tokens: Users manually enter the OTP. a. Connected tokens: Directly transmit the OTP to a computer via USB. b.
- 16. Antimalware Antimalware Software Software Scans software or files before they are run. Compares potential viruses against a database of known threats. Performs heuristic checking, which detects suspicious behavior in software that may indicate a virus, even if the virus is not in the database. Infected files are quarantined, allowing for automatic deletion or user decision. Needs regular updates to detect new viruses. Full system scans should be done weekly to detect dormant viruses.
- 17. Video Video Conferencing Conferencing Video conferencing uses both video and sound for communication. Hardware: Microphones Webcams Speakers Monitors/Screens Software: Hardware drivers CODEC Echo cancellation software Points to note: Agreeing on a time and date Set up needs to be checked Webcams and microphones should be placed approporiately Advantages: People from multiple regions can be connected easily Short notice conferences can be held Travelling costs are reduced Better for the environment Disadvantages: Time lag, images jerking Expensive set up Time zone differences Training might be required Good network connection required
- 18. Audio Audio Conferencing Conferencing Audio conferencing uses only sound as the method of communication. Hardware: Standard telephone network OR using VoIP (Voice over Internet Protocol) Computers Microphones Speakers Internet phone Standard phone Functioning: Organiser sends personal and participant’s PINs To dial in, a participant needs to add their PIN first followed by the personal PIN
- 19. Web conferencing (or webinars/webcasts) uses the internet to host real-time meetings, allowing multiple users to connect and participate in various activities Users join via an application or website link. The conference host controls speaking privileges. Delegates can raise a flag to request speaking time and post comments through instant messaging. Presentations can be uploaded in advance. Screen sharing for live presentations or demonstrations. Whiteboard tools for drawing or writing. Webcam usage for transmitting images or videos. Document sharing by uploading files before the conference. Web conferencing can be done on devices with webcams and microphones, such as tablets or smartphones, combining features of audio and video conferencing. Web Web Conferencing Conferencing
- 20. Microprocessor Microprocessor Controlled Controlled Devices Devices A microprocessor is a small electronic chip that acts as the brain of a computer, executing instructions and processing data. Microprocessor controlled devices are divided into: Labour saving Other (makes our lives easier/has additional features)
- 21. Microprocessor Microprocessor Controlled Devices Controlled Devices People no longer have to perform manual tasks at home. Automation gives more time for leisure, hobbies, shopping, and socializing. There's no need to stay home while tasks like cooking or washing clothes are being done. Smart devices, like ovens and washing machines, can be controlled remotely through smartphones. Automated burglar alarms offer a high level of security and intruder warning at all times. Smart fridges and freezers can promote healthier lifestyles by automatically ordering fresh food and reducing food waste. Advantages Advantages They can lead to unhealthy lifestyles due to lack of exercise, as people may become less active while devices perform tasks. They can encourage laziness, leading to over-reliance on the devices. There is a potential loss of household skills as tasks become automated. Devices with microprocessors and internet connectivity pose a risk of cybersecurity threats. Disadvantages Disadvantages