Computer Networks Lecture Notes PDF

Lecture 8 Detailed Summary ========================== Introduction to Computer Networks A computer network is a collection of computers and devices interconnected by wired or wireless communication channels.\ Networks are used to share resources like data, software, and devices such as printers an...

Lecture 8 Detailed Summary ========================== Introduction to Computer Networks A computer network is a collection of computers and devices interconnected by wired or wireless communication channels.\ Networks are used to share resources like data, software, and devices such as printers and scanners.\ Two primary types of networks based on connection methods are:\ - \*\*Wired Networks:\*\* Use physical cables for connection, common in schools, businesses, and government facilities.\ - \*\*Wireless Networks:\*\* Use radio waves for communication, widely used in homes and mobile setups. Types of Networks and Network Topologies Networks are classified based on their size and purpose:\ - \*\*Local Area Network (LAN):\*\* Covers a small geographic area like an office or home.\ - \*\*Wide Area Network (WAN):\*\* Spans large distances, connecting cities or countries.\ - \*\*Personal Area Network (PAN):\*\* For personal device connections, like Bluetooth.\ - \*\*Metropolitan Area Network (MAN):\*\* Covers a city or large campus.\ Topologies define the layout of network connections:\ - \*\*Star Topology:\*\* All devices connect to a central hub.\ - \*\*Bus Topology:\*\* All devices share a single communication line.\ - \*\*Ring Topology:\*\* Devices connect in a circular pattern. Network Architectures Network architectures determine how resources and devices are organized:\ - \*\*Client-Server Architecture:\*\* Centralized control where servers provide resources to clients. Examples include web and database servers.\ - \*\*Peer-to-Peer (P2P) Architecture:\*\* All nodes share resources equally without a central server. Examples include file-sharing systems like BitTorrent.\ P2P networks are easier to set up but may lack security and reliability. Transmission Media and Communication Protocols Transmission media are the channels for data transfer in a network:\ - \*\*Twisted-Pair Cable:\*\* Common in LANs, made of insulated copper wires.\ - \*\*Fiber Optic Cable:\*\* Provides high-speed transmission using light.\ - \*\*Wireless Media:\*\* Relies on radio waves, used in Wi-Fi and Bluetooth.\ Protocols ensure proper communication between devices:\ - \*\*TCP/IP:\*\* The backbone of the Internet, facilitating data transfer and addressing.\ - \*\*HTTP and HTTPS:\*\* Protocols for browsing web pages securely.\ - \*\*FTP:\*\* Used for transferring files over the Internet. Internet and World Wide Web (WWW) The Internet is a global network that connects users worldwide, governed by organizations like ICANN.\ The WWW is a multimedia layer of the Internet that enables access to websites via browsers like Chrome and Firefox.\ Important concepts include:\ - \*\*Web Pages and URLs:\*\* A web page is identified by its unique URL.\ - \*\*HTML:\*\* A markup language used to design web pages.\ - \*\*IP Addresses:\*\* Unique identifiers for devices on the Internet.