UNIT-1 CSE-306.pdf

💻 CSE306: MODULE 1:- Computer Networking: —>Computer networking is connection two or more computing devices together for the purpose of sharing data. —>its allows devices to communicate with each other, whether they are in...

💻 CSE306: MODULE 1:- Computer Networking: —>Computer networking is connection two or more computing devices together for the purpose of sharing data. —>its allows devices to communicate with each other, whether they are in the same room or across the world. Key aspects of computer networking include: Protocols: Rules that how data is transmitted between devices (e.g., TCP/IP, HTTP) Hardware: Physical components like routers, switches, and cables. Software: Programs that manage network operations and security. EX:→Computer networking enables various applications such as email, file sharing, video conferencing. Diagram:→home or small office network setup graph TD A[Internet] --> B[Router] B --> C[Switch] C --> D[Computer 1] C --> E[Computer 2] C --> F[Printer] B --> G[Wireless Access Point] G --> H[Smartphone] CSE306: 1  G --> I[Laptop] style A fill:#f9f,stroke:#333,stroke-width:4px style B fill:#bbf,stroke:#333,stroke-width:2px style C fill:#dfd,stroke:#333,stroke-width:2px style G fill:#ffd,stroke:#333,stroke-width:2px how different network components work together to enable data sharing and communication between devices. Important Term: Node —>Any communicating device in a network is called a Node. —>Node is the point of intersection in a network. It can send/receive data information within a network. —>Examples:-computers, laptops, printers, servers, modems, etc. Hosts: Devices that provide services or resources (e.g., servers, computers). Nodes: Devices that facilitate communication and routing within the network (e.g., routers, switches). CSE306: 2  Host —>A node that includes anything connected to a network, while a host requires an IP address. —>all hosts are nodes, but network nodes are not hosts. CSE306: 3  link A link or edge refers to the connectivity between two nodes in the network. connection can be wired or wireless between the nodes. CSE306: 4  Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. IP Address CSE306: 5  —>An IP address (Internet Protocol address) is a unique identifier assigned to each device connected to a computer network. —>IP addresses are unique identifiers used to determine who is who on the Internet. —>IP addresses are expressed as a set of four numbers. —>192.158.1.38. Each number in the set can range from 0 to 255. —>range 0.0.0.0 to 255.255.255.255. —>IPv6 addresses are 128 bits long and IPv4's 32-bit addresses. Networking Models: A networking model is a conceptual framework that describes how data communication occurs in computer networks. These models provide a structured approach. 1. OSI (Open Systems Interconnection) Model: The OSI model is a seven-layer conceptual framework developed by the International Organization for Standardization (ISO) in 1984. It describes how data should be transferred between two points in a network. The seven layers of the OSI model, from top to bottom, are: 1. Application Layer 2. Presentation Layer 3. Session Layer CSE306: 6  4. Transport Layer 5. Network Layer 6. Data Link Layer 7. Physical Layer 2. TCP/IP (Transmission Control Protocol/Internet Protocol) Model: The TCP/IP model is often described in four layers, but it can also be expanded to a five-layer model for more detailed analysis. Here’s the five-layer TCP/IP networking model: —>TCP/IP was designed and developed by the Department of Defense (DoD) in the 1960s and is based on standard protocols. —>TCP/IP model was developed alongside the creation of the ARPANET, which later became the foundation of the modern internet CSE306: 7  1. Application Layer 2. Transport Layer 3. network layer 4. Data link layer 5. Physical Layer Networking architecture: Explanation: —>how computers are organized and how tasks are allocated to the computer. —>Computer Network Architecture is defined as the physical and logical design of the software, hardware, protocols, and media of the transmission of data. Computer networks can be classified based on architecture into two parts: Peer-to-Peer Architecture Client/Server Architecture CSE306: 8  Peer-to-Peer Architecture(P2P): —>peers represent computer system. —>peer-to-peer (P2P) networking allows direct communication and resource sharing between participants(peers) without a central server. —>Peer-To-Peer network is useful for small environments, usually up to 10 computers. CSE306: 9  ADVANTAGE: 1. Cost-Effective: Reduces the need for expensive servers. 2. Flexibility: P2P networks can easily grow as more users connect. DISADVANTAGE: 1. Security Risks: More chances of viruses and hacking. 2. Legal Issues: Potential for copyright infringement and illegal file sharing. Client/Server Architecture: —>CSN (Client/Server Network) Client:—> The device or software that requests services. computer , laptop etc, Server: —>The system that provides resources or services. (e.g., web servers, database servers). note:—>The central controller is known as a server while all other computers in the network are called clients. CSE306: 10  ADVANTAGE: 1.Resource Sharing:—> Allows many users to use the same resources, making it more efficient. 2. Centralized Control: —>Easier to manage and secure data. DISADVANTAGE: 1. Single Point of Failure: —>If the server goes down, clients cannot access services. 2.Scalability Issues: —>Adding more users can overload the server. Protocol: —>The proper operation of computer networks depends on protocols. —>protocol in computer networks is like a set of rules that tells computers how to talk to each other. CSE306: 11  Types of Protocols: 1. TCP (Transmission Control Protocol): —>Makes sure data is sent and received accurately between devices. 2. IP (Internet Protocol): —>Helps route data to the right destination. 3. HTTP (Hypertext Transfer Protocol): —>Used for transferring web pages and data over the internet, allowing browsers to fetch and display content. 4. HTTPS (Hypertext Transfer Protocol Secure): —>A secure version of HTTP that encrypts data exchanged between the browser and server to protect user privacy. 5. FTP (File Transfer Protocol): —>Used for transferring files between computers and allowing users to upload or download files. 6. SMTP (Simple Mail Transfer Protocol): —>Used for sending emails and ensuring messages reach their intended recipients. CSE306: 12  7. DNS (Domain Name System): —>It converts easy-to-remember website names (like www.example.com) into IP addresses that computers use to find each other on the internet. 8. DHCP (Dynamic Host Configuration Protocol): —>Automatically assigns IP addresses to devices on a network, ensuring each device has a unique address. 9. SSH (Secure Shell): —>Provides a secure way to access and manage devices over a network by encrypting data to protect it from eavesdropping. 10. SNMP (Simple Network Management Protocol): —>Used for managing and monitoring network devices like routers, switches, and servers, collecting and organizing information about these devices. How they works: 1. Data Formatting: —>Protocols explain how data should be arranged when it's sent. 2. Error Checking: CSE306: 13  —>They can find and correct mistakes in the data. 3. Flow Control: —>They control the speed of data transfer to prevent sending too much at once. Protocol Standards: —>means protocol (Rules that help computers talk easily). Key Organizations 1. IETF (Internet Engineering Task Force 1986): —>This group creates and maintains standards for the Internet, like TCP/IP. Experts from around the world work together here. 2. IEEE (Institute of Electrical and Electronics Engineers 1963): —>This organization develops standards for technology, including networking standards like Ethernet(802.3) 1983 and Wi-Fi(802.11) 1997. 3. ISO (International Organization for Standardization 1947): —>ISO sets global standards in many fields, including information technology, which can affect networking practices. —>167 national standards organizations. 4. W3C (World Wide Web Consortium 1994): CSE306: 14  —>W3C focuses on web standards like HTML(1993) and CSS(1996), ensuring a consistent and accessible web experience for everyone. —>Over 400 organizations, including major tech companies and universities. Network hardware device: Repeater: —>A repeater operates at the physical layer. —>Its job is to amplifies (i.e., regenerates). —>they copy it bit by bit and regenerate it. the signal over the same network before the signal becomes too weak or corrupted to extend the length to which the signal can be transmitted over the same network. —>A typical repeater has two ports. Input Port: Receives the incoming signal from one device. Output Port: Sends the amplified and regenerated signal to another device. CSE306: 15  Hub: —>A hub is a basic networking device that connects multiple computers and devices in a local area network (LAN). CSE306: 16  —>When one device (like a computer) sends data, the hub receives that data and then broadcasts it to all other devices connected to it. —>Layer 1 Device Hubs operate at the physical layer of OSI model. Switch: When a device (let's call it Device A) wants to send data to another device (let's call it Device B), it creates a data packet (or frame) that CSE306: 17  includes: Source MAC Address: The MAC address of Device A. Destination MAC Address: The MAC address of Device B. Two Scenarios: If Device B's MAC is in the table: The switch knows the specific port (let’s say Port 2) where Device B is connected. The switch forwards the frame only to Port 2. If Device B's MAC is NOT in the table: The switch doesn’t know where Device B is, so it floods the frame to all other ports (except the one it came from). This means it sends the frame to every device connected to the switch. CSE306: 18  Router: —>A router is a device that forwards data packets between networks. Its main job is to manage data traffic and ensure that data reaches its correct destination. —>There are some popular companies that develop routers; such are Cisco, 3Com, HP, Juniper, D-Link, Nortel, etc. —>A router is used in LAN (Local Area Network) and WAN (Wide Area Network) environments. —>A router works on the third layer of the OSI model, and it is based on the IP address of a computer. —>Open Shortest Path First (OSPF) protocol.It is identified by the Internet Engineering Task Force (IETF) Advantages of a Router: 1. Connects Devices: Links multiple devices to the internet. 2. Manages Traffic: Helps data flow smoothly. 3. Enhances Security: Protects against online threats. 4. Segments Networks: Divides networks for better performance. CSE306: 19  5. Adjusts Routes: Finds the best path for data automatically. 6. Supports Protocols: Works with various internet standards. Disadvantages of a Router: 1. Costly: Good routers can be expensive. 2. Complex Setup: Can be hard to install for some users. 3. Single Point of Failure: If it breaks, the network goes down. 4. Limited Range: Wi-Fi may not reach far. 5. Overload Issues: Too many devices can slow it down. 6. Needs Maintenance: Requires regular updates. Network hardware architecture: —>Physical and logical arrangement of network components that help communication and data transfer between devices. Network topology: —>Topology defines the structure of the network. How all the components are interconnected to each other. (like nodes, links, or devices in a computer network). Types of Network Topology: Point-to-Point Topology: —>Only two devices are linked together. CSE306: 20  —>two end devices directly connect. (like two computers or a computer and a printer) 1. Easy to Set Up: —> It’s straight forward to connect two devices, making it simple to manage. 2. Limited Use: —>This setup is only for two devices, so if you want to connect more, you need additional point-to-point links. Bus Topology: Bus topology is a network configuration where all devices are connected to a single central cable, known as the bus or CSE306: 21  backbone cable. —>The bus topology is mainly used in 802.3 (ethernet) and 802.4 —> one backbone cable and N drop lines. —>Coaxial or twisted pair cables are mainly used that support up to 10 Mbps. —>When one device sends data, it travels along the bus and received by all other devices connected to it. CSE306: 22  CSMA Basics: —>CSMA helps devices share a communication channel so they don’t lose messages when trying to send data at the same time. 1. CSMA/CA (Collision Avoidance): —>This method prevents collisions by checking if the channel is busy before sending. If it is busy, the device waits until it’s clear, which helps avoid problems before they happen. 1. CSMA/CD (Collision Detection): —>This method finds out if two devices send messages at once CSE306: 23  (a collision). If a collision happens, the device stops sending and tries again later, focusing on fixing the issue after it occurs. —>The common method of bus topologies is CSMA (Carrier Sense Multiple Access). Limited Cable Length: —> The bus can only be so long, if it’s too long, then data to collisions, causing delays can slow down. Network Failure: —> If the main cable (bus) fails, the entire network goes down. Data Collisions: —> Multiple devices trying to send data at the same time can lead. Star Topology: All devices are connected to a central hub or switch. —>The central computer is known as a server, and the peripheral devices attached to the server are known as clients. —>Coaxial cable or RJ-45 cables are used to connect the computers. CSE306: 24  —>Point-to-point connection between hosts and hub. Advantage: If N devices are connected then the number of cables is N and Each device requires only 1 port. Ports required is N to connect to the hub. it is easy to set up If one link fails only that link will affect and not other than that. Fast performance with nodes and low network traffic. Disadvantage: CSE306: 25  A Central point of failure: —>If the central hub or switch goes down, then all the connected nodes will not be able to communicate with each other. —>The cost of installation is high. —>Performance is based on the single concentrator i.e. hub. How Does Star Topology Works: —>when any node wants to transmit data to another node it first transmits data to the central node which then transfers the data to all the nodes on the network. Once the node receives the data then it checks for the destination address if the address matches the data is accepted otherwise data is rejected. Ring Topology: CSE306: 26  —>The ring topology is used mainly on LANs as well as WANs. —> A Ring Topology connects devices in a circular format, where each device is linked to exactly two neighboring devices. —>Used in networks with a large number of nodes to prevent data loss. example, in a ring with 100 nodes, data must pass through 99 nodes to reach the last node. Token: —>A token is a special data packet or frame that circulates around the network. Only the device that holds the token can send data. How its work: —>A token travels around the ring stopping at each host. If a host wants to transmit data, the host adds the data and the destination address to the token. The token continues around the ring until it stops at the host with the destination address. The destination host takes the data out of the token. CSE306: 27  Advantages High-speed data transmission. Minimal collision possibility. Cost-effective to install and expand. Generally less expensive than star topology. Disadvantages A single node failure can disrupt the entire network. Adding or removing stations can disturb the entire topology. Less secure compared to other topologies. Mesh Topology: —>Each device (node) is connected to every other device in the network. CSE306: 28  1. Scalability: —>New nodes can be added without disrupting the network. 2. Redundancy: —>If one connection fails, data can still be transmitted through other connections. 3. High Performance: —>Data can be transmitted simultaneously between multiple nodes. —>If there are n number of nodes then each node will have n-1 number of connections. —>Total number of links required for the mesh topology is [n(n- 1)]/2. CSE306: 29  Advantages: Increased reliability and fault tolerance. Enhanced performance due to multiple data paths. Disadvantages: High installation and maintenance costs due to the number of connections. CSE306: 30  Complexity in wiring and configuration. Tree Topology: —>Tree topology is commonly used in large networks, such as in schools or organizations —>Tree topology combines the characteristics of bus topology and star topology. (It combines features of both bus topology (where all devices share a single communication line) and star topology (where each device connects to a central hub). —>Tree topology has a hierarchical structure. It starts with a central node (the root) and branches out to other nodes. —>Point-to-point wiring for individual segments. —>Tree Topology is highly secure. It is used in WAN. Advantage: Easy to Expand: Adding new devices is straightforward. CSE306: 31  Fault Isolation: If one branch fails, it doesn’t affect the entire network, making it easier to locate issues. Disadvantages: Complexity: The structure can become complicated as more nodes are added. Dependency on Central Node: If the root node fails, the entire network can be affected. Hybrid Topology: Combination of two or more network topologies, such as mesh topology, bus topology, and ring topology. 1. Scalability: Easy to add new devices or nodes without disrupting the entire network. 2. Robustness: If one part of the network fails, other parts can continue to operate. CSE306: 32  Advantage: Traffic with large volume is handled easily by the hybrid topology. The overall performance and speed is greater in hybrid topology. Disadvantages: The design and implementation of hybrid network topology is difficult. The process of installation of hybrid topology is difficult. The overall implementation, setup and process of hybrid topology is much more costlier Uses of Computer Networks, Networks and Types: Computer networks help people talk to each other, share files, and use resources easily. They allow access to work from anywhere, making teamwork better. Networks also connect us to the internet and support many online services we use every day. CSE306: 33  1. Communication: Computer networks enable quick and easy communication through emails and messaging apps. This helps people connect regardless of distance. 2. File Sharing: Users can share documents and files effortlessly, making collaboration simpler. Services like Google Drive allow multiple people to access the same files. 3. Remote Access: Networks allow users to access work systems from anywhere, enhancing flexibility. This is especially useful for remote work and travel. 4. Internet Connectivity: Networks connect users to the internet, providing access to information and online services. This is essential for everyday tasks and activities. Networks and Types: A network is a collection of interconnected devices that can communicate and share resources with each other. This can include computers, servers, printers, and other devices. Types of Networks: Wireless Local Area Network (WLAN): Local Area Network (LAN): LAN stands for Local Area Network, its connects computers and devices within a limited geographical area, such as a home, school, office, or building. The data is transferred at an extremely faster rate in Local Area Network. Local Area Network provides higher security. —>speeds are normally 100 or 1000 Mbps. LAN has a range up to 2km. —>wired or wireless. CSE306: 34  Wide Area Network (WAN): —>Computer network that extends over a large geographical area. —>(state or country)WAN has a range of above 50 km. Communicate between devices in any part of the world —>A Communication medium used for WAN is PSTN(Public Switched Telephone Network) or Satellite Link. —>Due to long-distance transmission, the noise and error tend to be more in WAN. —>WAN’s data rate is slow about a 10th LAN’s speed (because distance). CSE306: 35  —>The speed kilobits per second (Kbps) to megabits per second (Mbps) —>In the late 1950s, the Wide Area Network was first designed by the U.S. Air force. United States defence in which they developed the ARPANET, Disadvantages of WAN: 1. High Costs: Initial setup and ongoing maintenance can be expensive. 2. Complexity: Requires skilled personnel for management and troubleshooting. 3. Latency Issues: Higher latency can affect performance for real-time applications. 4. Security Risks: Increased exposure to vulnerabilities necessitates robust security measures. 5. Bandwidth Limitations: May face constraints that impact data transfer speeds. Metropolitan Area Network (MAN): —>A computer network typically used to connect computers in a metropolitan area (large geographical area) such as a city or university. CSE306: 36  —>It is bigger than a LAN and smaller than a WAN. It covers a range of up to 50 km and uses telecommunication media within the city. —>It connects various LANs. For example, it may connect branch offices to head offices within the same city. The metropolitan area uses switches or hubs to establish a LAN and routers or bridges to connect to other LANs —>Fiber optics are considered the backbone of MANs. Provide high-speed data communication Ownership Private or public Maintenance Difficult Error rate and cost High Personal Area Network (PAN): —>Personal Area Network is a network arranged within an individual person and used for connecting the computer devices of personal use. —> Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network. —>It covers only less than 10 meters or 33 feet of area. CSE306: 37  —>Wired(use usb) and Wireless(wifi). —>Body Area Network is a network that moves with a person(phone) Disadvantages: Limited coverage area. Not be able to handle large amounts of data or high-speed communication. Virtual Private Network (VPN): —>A VPN (Virtual Private Network) is a tool that helps you create a secure connection to another network over the Internet. It keeps your online activities private and protects your data —>A VPN encrypts your internet traffic, which means it turns your data into a code so that others can’t read it. Hiding Your Real IP Address, Effect on Your Location : —>When you use a VPN, your real IP address (which shows your location) is hidden. CSE306: 38  —>When you use a VPN, you first connect to a VPN server. This server could be located anywhere in the world. —>using a VPN changes your visible IP address to that of the VPN server, protecting your privacy and allowing you to access content from different locations. Advantage: —>if a hacker intercepts the data, they will not be able to read it. —>A VPN masks the user’s IP address, making it difficult for websites and online services to track their online activity. Disadvantage: CSE306: 39  —>performance issue with respect to time. —>sometimes your VPN provider company itself steals your data, which can cause security issues. Introduction to: Note:—>The Internet is an infrastructure, whereas the Web is a service built on top of the infrastructure. Internet: The Internet is the backbone of the Web, a large network of computers that communicate together, making the Web possible. Web—> World Wide Web (WWW): —>The web is a global information system that allows users to access and share content over the internet —>The web was invented by Tim Berners-Lee in 1989 at CERN, and opened to the public in 1991. —>The web is the primary way that billions of people around the world interact with the internet. webpage A document which can be displayed in a web browser such as Firefox, Google Chrome, Opera, Microsoft Edge, or Apple Safari. These are also often called just "pages." —>by IP. CSE306: 40  website A collection of web pages which are grouped together and usually connected together in various ways. Often called a "website" or a "site." —>by DNS web server A computer that hosts a website on the Internet. search engine A web service that helps you find other web pages, such as Google, Bing, Yahoo, or DuckDuckGo. CSE306: 41  How the web works: Clients are the typical web user's internet-connected devices (for example, your computer connected to your Wi-Fi, or your phone connected to your mobile network) and web-accessing software available on those devices (usually a web browser like Firefox or Chrome). Servers are computers that store webpages, sites, or apps. When a client device wants to access a webpage, a copy of the webpage is downloaded from the server onto the client machine to be displayed in the user's web browser. TCP/IP: Transmission Control Protocol and Internet Protocol are communication protocols that define how data should travel across the internet DNS: Domain Name System is like an address book for websites. HTTP: Hypertext Transfer Protocol is an application protocol that defines a language for clients and servers to speak to each other. Component files: A website is made up of many different files. Code files: Websites are built from HTML, CSS, and JavaScript. so on. Assets: This is a collective name for all the other stuff that makes up a website, such as images, music, video, Word documents, and PDFs. CSE306: 42  Web Server: A web server is a computer hosting one or more websites. "Hosting" means that all the web pages and their supporting files are available on that computer. The web server will send any web page from the website. —>The term web server can refer to hardware or software, or both of them working together. —> HTTP specifies how to transfer hypertext (linked web documents) between two computers. Static Web Server Definition: A static web server delivers fixed content that does not change in response to user interactions. Example: A personal portfolio website hosted on GitHub Pages, where the HTML, CSS, and images remain the same for all users. Dynamic Web Server Definition: A dynamic web server generates content on-the-fly based on user requests, often pulling data from databases. Example: An e-commerce site like Amazon, which displays different products and user-specific information by retrieving data from a backend database. CSE306: 43  Apache HTTP Server Popularity: Most widely used web server (about 60% market share). Type: Open-source. Flexibility: Users can modify the code. Compatibility: Works on various operating systems (Linux, MacOS, Windows). 2. Microsoft Internet Information Services (IIS) Developer: Microsoft. Integration: Strongly integrated with Windows OS. Support: Good customer support available. Type: Proprietary (not open-source). Features: Similar to Apache but lacks code modification capabilities. CSE306: 44  3. Lighttpd: Market Share: Runs about 0.1% of websites. Performance: Low CPU and memory footprint. Speed: Offers speed optimization options. Type: Open-source. Flexibility: Users can modify the code. 4. Jigsaw Server Language: Written in Java. Functionality: Can run CGI scripts and PHP. Purpose: Experimental server for new web protocols. CSE306: 45  Type: Open-source. Compatibility: Requires a Java-supporting device. 5. Sun Java System Support: Supports various Web 2.0 technologies (e.g., Python, PHP). Type: Proprietary (not open-source). Limitations: Code is inaccessible for modifications. Web browser: WorldWideWeb (1990): The first web browser, created by Tim Berners- Lee. Mosaic (1993): The first widely used graphical web browser, developed by Marc Andreessen and Eric Bina. Netscape Navigator (1994): Built on Mosaic's code, it became the dominant browser of the mid-1990s, introducing features like bookmarks and secure connections. CSE306: 46  How its work: —>working model is called a client-server model. The browser receives information through HTTP protocol. In which transmission of data is defined. When the browser received data from the server, it is rendered in HTML to user-readable form and, information is displayed on the device screen. 1. Google Chrome 2. Mozilla Firefox 3. Safari 4. Microsoft Edge 5. Opera 6. Brave URL(Uniform Resource Locator): IP address ,it is a unique number that is assigned to each device on a network. A domain name is assigned a unique IP address on the World Wide Web. CSE306: 47  Packet: —>A small segment of a larger message that is transmitted over a network. 1. Header: Contains essential metadata, including: Source Address: The IP address of the sender. Destination Address: The IP address of the recipient. Protocol Information: Indicates the communication protocol used (e.g., TCP, UDP). Sequence Number: Helps in reordering packets if they arrive out of sequence. CSE306: 48  2. Payload: The actual content or data being transmitted, such as part of a file, a web page, or any other type of information. 3. Trailer (optional): May include error-checking data (like checksums) to verify the integrity of the packet. Contains Packet Header Payload Trailer (optional) Coursera Module1 TCP/IP MCQ: practice.mcq —>subscribe my youtube chanel also please for notes explanation video. —>whycodemrbean (chanel name) —>unit 2 and unit 3 notes also ready but one one topic are not. CSE306: 49