LAN (Local Area Network)
Local Area Network (LAN) A Local Area Network (LAN) is a network confined to a small geographical area, such as a home, office, or campus. It enables fast, reliable communication and resource sharing among devices. 🔹 Key Characteristics of LAN Geographical Scope: Typically within 1 km² (building, floor, or campus). Ownership: Usually privately owned and managed. Data Transfer Speed: High — typically 100 Mbps to 10 Gbps or more. Latency: Low, due to proximity of devices. Transmission Medium: Twisted pair cables, fiber optics, or wireless (Wi-Fi). Maintenance: Managed internally by network administrators. 🔹 Functions of a LAN Sharing files, printers, and internet access. Centralized software and user management via servers. Facilitates local email and internal chat systems. Local hosting of web services and databases. 🖼️ Textual Diagram – Typical LAN Setup +-----------+ +-----------+ | Laptop | | Printer | +-----------+ +-----------+ \ / \ / +---------------------+ | Ethernet | ← Switch/Hub +---------------------+ / \ +-----------+ +-----------+ | Desktop 1 | | Desktop 2 | +-----------+ +-----------+ | +------------+ | Router | +------------+ | [Internet] 🔹 Types of LAN 1. Wired LAN Uses physical cables (typically Ethernet). Offers high speed, low interference. Common in offices and server rooms. 2. Wireless LAN (WLAN) Uses radio waves (Wi-Fi). More flexible and mobile. Common in homes and cafes. 🔹 LAN Protocols Protocol Description Ethernet (IEEE 802.3) Most widely used wired LAN protocol. Uses CSMA/CD. Wi-Fi (IEEE 802.11) Wireless LAN standard. Uses CSMA/CA. Token Ring (IEEE 802.5) Older LAN protocol; now mostly obsolete. MAC Addressing Uniquely identifies devices at the Data Link Layer. 🔹 Advantages of LAN High Speed: Up to 10 Gbps with modern Ethernet. Low Cost: Infrastructure and maintenance are affordable. Security: Managed internally with firewalls, access control. Resource Sharing: Centralized access to printers, storage, and internet. 🔹 Disadvantages of LAN Limited Range: Only suitable for small areas. Initial Setup Cost: Requires cabling, switches, routers. Maintenance: Needs network administration knowledge. 🔹 Use Cases Educational Institutions: For connecting labs, classrooms, libraries. Businesses: Centralize data and applications on servers. Homes: Sharing internet, streaming, file transfers between devices. 🔹 LAN Topologies LANs can be implemented using different topologies: ...