Computer_Networks_Unit1_Detailed dsds.pptx

dsd

1. Unit I - Introduction to Networks Definition: Set of devices (nodes) connected by communication links Nodes: Computers, printers, or devices capable of data exchange Connections: Wired (copper, fiber) or wireless (satellite, microwave, infrared) Difference between Computer Networks and Distributed Systems

2. Unit I - Uses of Networks Business Applications: Resource sharing, client-server model, email, VoIP, e-commerce Home Applications: Peer-to-peer, entertainment, e-commerce Mobile Users: Text messaging, smartphones, GPS, m-commerce Social Issues: Privacy, censorship, phishing, botnet attacks

3. Unit I - Network Criteria Performance: Transit time, response time, throughput, delay Reliability: Failure frequency, recovery time, robustness Security: Protecting data from unauthorized access, damage, and breaches

4. Unit I - Data Communication Components Message: Information to be communicated Sender & Receiver: Devices transmitting/receiving data Transmission Medium: Path between sender and receiver Protocol: Set of rules governing communication

5. Unit I - Data Flow Simplex: One-way communication (keyboard, monitor) Half-duplex: Two-way but one at a time (walkie-talkie) Full-duplex: Two-way simultaneously (telephone)

6. Unit I - Physical Topology Mesh: Every node connected to every other node Star: Nodes connected via central hub/switch Bus: All devices share a single backbone cable Ring: Devices connected in a circular path Hybrid: Combination of two or more topologies

7. Unit I - Types of Networks LAN: Local Area Network – small area (e.g., school lab) MAN: Metropolitan Area Network – city-wide connections WAN: Wide Area Network – country/worldwide (Internet) Other: WLAN, PAN, SAN

8. Unit I - Transmission Media Guided: Twisted-pair, Coaxial, Fiber-optic cables Unguided (Wireless): Radio waves, Microwaves, Infrared

9. Unit I - Switching Techniques Circuit Switching: Dedicated path for entire session Packet Switching: Data divided into packets (datagram & virtual circuit) Message Switching: Store-and-forward method

10. Unit I - Reference Models OSI Model: 7 layers (Physical → Application) TCP/IP Model: Application, Transport, Internet, Network Access Comparison: Layer functions and relationships

11. Unit I - Internet Architecture History: ARPANET → TCP/IP Hierarchical structure: ISPs (International, National, Regional, Local) Concept of NAPs and Peering points Internet as a network of networks