Chapter 11- Emerging Technologies - Sub topic Communications technology
- 2. Network Models TCP/IP AND OSI All Networks are built upon these two models These models provide the protocols and rules for communication and data sharing over the network Each has different layers Each layer of the model performs a specific function
- 3. OSI – OPEN SYSTEMS INTERCONNECTION OSI stands for Open Systems Interconnection, where open stands to say non-proprietary. It is a 7-layer architecture with each layer having specific functionality to perform. All these 7 layers work collaboratively to transmit the data from one person to another across the globe.
- 8. TCP/IP Model • The TCP/IP model is a framework for computer networking. • It stands for Transmission Control Protocol/Internet Protocol • This model defines how data is transmitted over networks, ensuring reliable communication between devices. • It consists of four layers: the Link Layer, the Internet Layer, the Transport Layer, and the Application Layer. • Each layer has specific functions that help manage different aspects of network communication, making it essential for understanding and working with modern networks.
- 9. What Does TCP/IP Do? • The main work of TCP/IP is to transfer the data of a computer from one device to another. • The main condition of this process is to make data reliable and accurate so that the receiver will receive the same information which is sent by the sender. • TCP/IP model divides its data into packets and combines them at the other end, which helps in maintaining the accuracy of the data while transferring from one end to another end.
- 11. Structure of data packets in network • The main function of a network is to transmit data from one device to another. • Data is packaged into packets • Packets contain – elements which are Header, the payload and trailer • Header - the header is the box or envelope (contains IP and MAC address) • Payload - the payload is content • Trailer - the trailer is the signature
- 12. Transmitting Data Packets • In networking transmitting data packet is called “Switching” • There are 3 main switching • Circuit Switching • Packet Switching • Message Switching
- 13. Circuit Switching • A direct path is created between the sending and the receiving device. • These are dedicated pathways to transmit the data packet from one device to another. • No other device can transmit data by the path in the network until the transmission is done. • Once the transmission is completed then the path can be used by other devices
- 14. Packet Switching • Data packets can take any available path • There is no set pathway • Normally used when packets are sent across the internet • Data is Sent via routers • 2 types – connection- oriented and connectionless
- 15. Message switching • In message switching the entire message is transmitted without any break from one node to another. • The data packets are sent from one computer to one switch device, it then holds the entire data until all packets are received and then passes to the next …this repeats until the packet reaches the destination. • Store and forward method
- 16. Network Structures • Peer-to-Peer • Client-server
- 17. Peer-to-Peer • All computers are known as peers. • Can be 2 or 100s of computers • Main reason is to share data • Doesn't have any central point of control. • Each user stores data, they can choose to keep it private or public. • Resources like printers can be shared • Used as a file-sharing system
- 18. Example • if one student has summarized notes for a particular topic, they can share it with the rest of the group by making copies or simply showing it to others. Another student might have found useful online resources or practice questions, which they can share with the group. The students can discuss and explain concepts to each other, asking questions and clarifying doubts. • no one student is solely responsible for providing all the information. Instead, each student contributes knowledge and resources, and everyone benefits from the collective effort. If one student is absent, it doesn’t stop the others from studying and sharing information. The study group functions efficiently because the peers are directly interacting and sharing resources without relying on a central authority.
- 19. Client-server • Contains 2 types of computers- client and server • Servers are the central point of control • The client computers are connected to the server • This network operates on request-response method. • Servers are very expensive computers • Have huge processing powers. • Many servers are grouped to ease and divide tasks these are called server farm
- 20. Example imagine a group of friends studying together for an exam. In a traditional classroom setting (client-server architecture), there is a teacher who serves as a central authority and provides information to all the students (clients). The students rely on the teacher for the necessary study materials and guidance.
- 21. https://www.youtube.com/watch?v=ewrBalT_eBM https://www.youtube.com/watch?v=LkolbURrtTs Data Packets OSI Models https://www.youtube.com/watch?v=gB0DCb84T7c Circuit and Packet Switching Understanding the concepts better………………
- 22. Server Types of Client-Server Network A server is defined as a powerful machine designed to compute, store, and manage data, devices, and systems over a network. • File servers are typically used for storage purposes. • A file server refers to a machine that provides shareable disks that can be accessed by the workstations on a network. File Server • Stores, processes and transmits web pages • They support protocols such as HTTP, FTP, and SMTP that are key to information exchange between network devices. Web Server
- 23. • A mail server facilitates email storage and management for clients. • It uses different protocols for sending and receiving emails. For example, the Simple Mail Transfer Protocol (SMTP) is used to send an email. The server relies on the Post Office Protocol (POP3)l to store and receive an email. Mail Server • Installs and runs software applications • Application servers are much like web servers as they tend to use HTTP protocol and answer client requests. Application Server • Receives print jobs from client computers ad sends them to correct printer. • Many client computers can use a range of printers available Print Server • Manages the transfer of data that uses the file transfer protocol(FTP) • It keeps a log of all activities involving FTP FTP Server • Acts as an intermediary between clients and other servers by receiving client requests and forwards them on relevant servers. • Provides added level of security by protecting clients from direct access of servers Proxy Server
- 24. VPN-Virtual Private Network • A protected network connection when using public networks. • VPNs encrypt your internet traffic and disguise your online identity. • This makes it more difficult for third parties to track your activities online and steal data. The encryption takes place in real time. How does a VPN work? • A VPN hides your IP address by letting the network redirect it through a specially configured remote server run by a VPN host. • A VPN connection disguises your data traffic online and protects it from external access. • Unencrypted data can be viewed by anyone who has network access and wants to see it. With a VPN, hackers and cyber criminals can’t decipher this data.
- 25. Mobile Network/Cellular Network • A mobile network (also wireless network) route's communications in the form of radio waves to and from users. • It is composed of base stations that each cover a delimited area or "cell." When joined together these cells provide radio coverage over a wide geographic area. • At the heart of each cell there is a radio base station that transmits and receives messages. • Cells vary in sizes covering a certain area or distance. • Picocells cover 200 meters, microcells cover 2 kms, macrocells cover larger regions.
- 26. Generations of Mobile Networks • First Generation (1G) - First-generation mobile networks relied on analogue radio systems, which meant that users could only make phone calls and not send or receive text messages. • Second Generation (2G) - The 1G network was not perfect, but it remained until 1991, when it was replaced with 2G. This new mobile network ran on digital signal, not analogue, vastly improving its security and capacity. On 2G, users could send SMS and MMS messages • Third Generation (3G) - Third-generation mobile networks are still in use, but normally, when the superior 4G signal fails. 3G revolutionized mobile connectivity and the capabilities of cell phones. Compared to 2G, 3G was much faster and could transmit greater amounts of data. This means that users could video call, share files, surf the internet, watch TV online, and play games on their mobiles for the first time.
- 27. • Fourth Generation (4G) - It is five times faster than the 3G network. Under 4G, users can experience better latency (less buffering), higher voice quality, easy access to instant messaging services and social media, quality streaming, and faster downloads. • Fifth Generation (5G) - The network has changed more than our mobile use and affects how we connect our devices to the internet. The improved speed and the massive network capacity have developed new IoT trends, such as smart cities, healthcare, IoT in the home or office and connected cars.
- 28. Network Protocols • Tunnelling – Secure transmission of data over networks. Sends private data packets across a public network through encapsulation. • SSL – A network protocol- ensures connections between client and servers are secure. uses encryption method to send data over network. It has been now replaced by TLS. • Transport Layer Security – updated version of SSL. Uses more secure encryption algorithms. • Internet Protocol security(IPsec) – Encrypts and authenticates data packets that are sent across internet. IPsec is a part of tunnelling. • BitTorrent – A communication protocol used in peer-to-peer file sharing.
- 29. Large Files like videos can be transferred. The load is distributed over several sources on the network. These sources(host) are called swarm. The file is downloaded in pieces from different sources. Then rearranges the pieces to complete the file. Leechers are users who are currently downloading a file but have not yet completed the download on the BitTorrent file-sharing network. A peer or downloader becomes a seed when it completely downloads all the data and continues/starts uploading data for other peers to download from.
- 31. Components in a network • First device to connect to internet. • NIC stands for network interface card. • There are two types of NIC: 1.Wired NIC 2.Wireless NIC • Wired NIC: The Wired NIC is present inside the motherboard. Cables and connectors are used with wired NIC to transfer data. • Wireless NIC: The wireless NIC contains the antenna to obtain the connection over the wireless network. For example, laptop computer contains the wireless NIC
- 32. Hubs and Switches • A hub is a basic networking device that allows multiple devices to communicate with each other. • Hubs receive data packets from one device and broadcast them to all the other devices connected to the hub. This means that all devices on the network share the same bandwidth and receive all data, regardless of whether it is intended for them or not. • There are mainly two types of hubs: passive and active.
- 33. • Passive hub: A passive hub simply connects all devices together, without any signal amplification or regeneration. It has no power source and does not boost the signal, so it is not suitable for long- distance connections or large networks. A passive hub is mainly used to extend the number of ports available on a network. • Active hub: An active hub, also known as a powered hub, has a power source and can regenerate and amplify the signal. This means that it can transmit data over longer distances and support more devices than a passive hub. An active hub also has built-in circuitry that helps to prevent collisions, which occur when two or more devices attempt to transmit data at the same time.
- 34. Switch switch is a networking device that connects multiple devices in a network, allowing them to communicate with each other. Unlike a hub, which broadcasts data to all devices on the network, a switch forwards data only to the intended recipient, which reduces network congestion and improves performance.
- 35. Repeaters • A repeater is a networking device and of the components of computer network that is used to regenerate and amplify signals in a network. When data is transmitted over a network, the signal weakens as it travels through the network cables. A repeater receives the weak signal and regenerates it, amplifying the signal to its original strength. This allows the signal to be transmitted over longer distances without loss of quality. • Retransmits analogue and digital data
- 36. Wireless Access Point (WAP) • Wireless access points (WAPs) are devices that allow you to connect to a wired/wireless network and access the internet. They are often used in homes and businesses to extend the range of a wireless network or to provide wireless access in areas where it is not possible to run Ethernet cables. • Often have a limit of connecting 15-20 devices. • Large organizations have multiple WAPs
- 37. Bridges, Gateways and Routers • A bridge is a network device that connects two or more LANs (local area networks) to form a larger LAN. • The gateway in networking is a device that connects the Internet to the LAN. It can even be used as a bridge between two networks. • A Router is a networking device that forwards data packets between computer networks. • Router assigns an IP address to each device connected to it. • Router is used to connect LANs and also to connect LANs to WANs
- 38. Which Device Works on Which Layer of OSI 1.HUB works in the physical layer(Layer 1) of the OSI model. 2.Switches operate in the data link(Layer 2) layer of the OSI model. 3.Bridge operates at the data link layer of the OSI model. 4.The router is essentially a Network Layer device. 5.Gateways operate at the network layer of the OSI model. 6. Brouter can work either at the data link layer or a network layer. 7.NIC card works on both the physical and data link layer of the OSI model. 8.The firewall operates on the network layer of the OSI model. 9.RJ45 works on the Physical Layer of the OSI model.
- 39. Network Connections(PHYSICAL) • Coaxial – copper cables covered with a jacket of insulating layers these carry radio frequency signals. Used in Cable TV connections and internet connections • Twisted Pair – copper cables with 2 pair of insulated wires twisted together. Transmit electric current. Used for telephone communications and ethernet network • Fibre Optic – made up of thread of glass. Use properties of light to transmit data. Used in modern day internet connections and high performance networks.
- 40. • Uses radio waves to transmit data between devices. • WiFi- most common method used. Each device which wants to make a connection will send a radio signal to the router or WAP and these will process the data. Transmits data with much higher frequencies than mobile networks. • Bluetooth – Use radio signals Network Connections(WIRELESS)