--- type: "Chapter" knowledge_type: "chapter" generated_at: "2023-10-08T12:00:00Z" entity_type: "chapter" id: "66def9c83f8b4e9e69bdbe5b" title: "Computer Networks" board: "CBSE" curriculum: "CBSE" class: "Class 12" subject: "Computer Science" book: "Computer Science" chapter: "Computer Networks" chapter_slug: "computer-networks" canonical_url: "https://www.edzy.ai/cbse-class-12-computer-science-computer-networks" markdown_url: "https://www.edzy.ai/okf/chapter/cbse-class-12-computer-science-computer-networks.md" source_type: "examSubjectBookChapter" source_id: "66def9c83f8b4e9e69bdbe5b" source_pdf: "https://edzy-ai.s3.ap-south-1.amazonaws.com/edzy-express-ts/443e2d85-0c6f-48f8-9a5c-96ba6c4a4ac9.pdf" source: "Edzy" version: 1 last_updated: "2026-06-20" --- # Computer Networks This chapter explores the fundamental concepts of computer networks, their evolution, types, network devices, topologies, identification of nodes, and the role of the Internet. --- ## Knowledge Snapshot | Field | Details | | :--- | :--- | | Class | Class 12 | | Subject | Computer Science | | Book | Computer Science | | Chapter | Computer Networks | | Pages | 181-202 | --- ## Chapter Summary ### Short Summary The chapter covers various aspects of computer networks, discussing their types, evolution, devices involved, networking topologies, the Internet, and the Domain Name System. ### Detailed Summary Computer networks facilitate the sharing of data and resources between interconnected devices, allowing various forms of communication like emails and video calls. It delineates the evolution of networking from ARPANET to the modern Internet, the classification of networks into PAN, LAN, MAN, and WAN, detailed descriptions of networking devices such as modems, routers, switches, and the concept of network topologies. Furthermore, it includes the significance of the Internet, the World Wide Web, and the Domain Name System. --- ## Topic-Wise Explanation ### Introduction to Computer Networks A network is defined as a group of interrelated entities allowing resource sharing and communication. Computer networks specifically enable data exchange between computing devices through wired or wireless connections. ### Evolution of Networking The history of networking began with ARPANET in the 1960s, marking the start of efforts to connect various institutions for collaborative research. Key developments include the introduction of TCP/IP, the establishment of the Domain Name System, and the commercialization of networking services. ### Types of Networks Computer networks are categorized into: - PAN: Personal Area Network for devices within 10 meters. - LAN: Local Area Network that connects devices in small geographical areas. - MAN: Metropolitan Area Network covering larger areas like towns or cities. - WAN: Wide Area Network connecting multiple LANs and MANs over vast distances. ### Network Devices Essential devices for networking include: - **Modem**: Converts digital data to analog signals and vice versa. - **Ethernet Card**: Connects a computer to a network. - **Repeater**: Regenerates weakened signals. - **Hub**: Connects devices, sending data to all. - **Switch**: Directs data to specific devices. - **Router**: Connects multiple networks, forwarding data intelligently. - **Gateway**: Acts as the access point between different networks. ### Networking Topologies Networking topologies refer to the physical or logical arrangement of devices. Common types include: - **Mesh**: Every device is interconnected. - **Ring**: Nodes connect in a closed loop. - **Bus**: All devices share a single communication line. - **Star**: All devices connect to a central node. - **Tree**: A hybrid structure supporting various topologies. ### Identifying Nodes in a Networked Communication Nodes are identified using MAC and IP addresses. MAC addresses are hardware-specific and permanent, while IP addresses can change based on the network. ### Internet, Web and the Internet of Things The Internet functions as the global network connecting various computing devices. The Web is a vast collection of connected pages accessed via the Internet, and IoT refers to everyday devices communicating over networks. ### Domain Name System The DNS translates human-friendly domain names to IP addresses, simplifying access to websites. --- ## Core Ideas | Idea | Explanation | | :--- | :--- | | Network Interconnection | Facilitates data sharing among related devices. | | Evolution of Networking | Traces the development from ARPANET to contemporary Internet systems. | | Types of Networks | Different categorization based on range and communication technology. | --- ## Key Concepts | Concept | Meaning | | :--- | :--- | | ARPANET | The first decentralized network project. | | TCP/IP | Set of communication protocols used on the Internet. | | MAC Address | Unique identifier assigned to network interfaces. | | IP Address | Numerical label assigned to each device on a network. | | DNS | System for converting domain names to IP addresses. | --- ## Important Points for Revision * Networks allow sharing of data and resources. * Different types of networks include PAN, LAN, MAN, and WAN. * Networking devices help in data communication and network configuration. * Topologies determine the arrangement of devices in a network. * Each device in a network is identified by a unique address. * The Internet connects a vast number of devices and networks worldwide. * The World Wide Web is built upon the Internet's infrastructure. * DNS simplifies web navigation by translating domain names. * Each IP address is unique and can change based on network connectivity. --- ## Vocabulary and Glossary | Word / Phrase | Meaning | | :--- | :--- | | Modulator | Device converting digital signals to analog and vice versa. | | Node | Any device within a network capable of sending/receiving data. | | Protocol | Rules governing data exchange in networks. | --- ## Practice Questions ### Short Answer Questions 1. Define a computer network. 2. What is a LAN? 3. Explain the role of a router in a network. 4. List the types of networks based on geographical coverage. 5. What is the function of a modem? ### Long Answer Questions 1. Discuss the evolution of computer networks from ARPANET to the present day. 2. Compare and contrast LAN and WAN. 3. Describe the different networking topologies and their applications. 4. Explain the significance of the Domain Name System in Internet navigation. --- ## Related Concepts * Internet Security * Network Protocols * Data Communication * Information Technology --- ## Source Attribution | Field | Value | | :--- | :--- | | Source | Edzy | | Reference Type | examSubjectBookChapter | | Reference ID | 66def9c83f8b4e9e69bdbe5b | | Canonical URL | https://www.edzy.ai/cbse-class-12-computer-science-computer-networks | | Markdown URL | https://www.edzy.ai/okf/chapter/cbse-class-12-computer-science-computer-networks.md |