Grade 11 Computer Applications Technology - Local Area Network (Module 2.1)

Network Types & Overview

  • Local Area Network (LAN): Connects computers across a small geographical area, such as a school or office building.

  • Personal Area Network (PAN): A network organized around an individual person within a single location.

  • Home Area Network (HAN): A network contained within a user's home connecting digital devices.

  • Internet: A global system of interconnected computer networks.

Computing Devices & Server Roles

  • Workstations: Desktop computers providing a designated space to connect to and work on a network.

  • Clients: Any computing device or peripheral that interacts with a network to use shared resources.

  • Servers: High-performance computers providing dedicated services to network users:

    • File Servers: Central storage for files and shared folders.

    • Email Servers: Handle, send, receive, and organize organizational email.

    • Internet / Proxy Servers: Perform security filtering, virus checking, and monitor web usage.

    • Web Servers: Host websites.

    • Print Servers: Manage printing tasks and user access permissions for printers.

    • Database Servers: Provide access to central structured data.

  • Network Architectures:

    • Client-Server Network: Computing devices must sign in to a central server to access network services.

    • Peer-to-Peer Network: Connected devices communicate directly with one another without a central server, primarily sharing an internet connection.

Network Hardware Components

Diagram of a simple LAN network setup connecting routers, switches, servers, access points, and devices

  • Network Interface Controller (NIC): Hardware component required by every device to connect to a network; can be a built-in wired or wireless adapter.

  • Switch: Central hardware device in a wired network with physical ports where ethernet cables plug in to connect devices.

  • Access Point (AP): Hardware containing a transceiver and antenna to transmit radio waves, creating a wireless network area.

  • Router: Connects a LAN or HAN to an external network (the internet); modern home routers typically integrate a router, switch, and wireless access point into one unit.

Communication Media: Wired vs. Wireless

Coiled blue Unshielded Twisted Pair UTP ethernet cable with RJ-45 connectorsFibre optic cable bundle showing light signals transmitted through glass strands

  • Unshielded Twisted Pair (UTP): Most common copper cabling used in local wired connections.

  • Fibre Optic Cable: Uses light pulses to transmit data through glass strands.

    • Comparison: Fibre optic is faster, spans greater distances, is immune to electromagnetic interference (EMI) and eavesdropping, but is more expensive and complex to install than UTP.

  • Wireless LAN (WLAN): Transmits data over radio waves without physical cables, offering higher flexibility and easier installation.

  • Transmission Speeds:

    • Network performance is determined by the speed of the slowest connected component.

    • Hardware speed ratings like 100/1000 represent 100 Mbps100\text{ Mbps} or 1000 Mbps1000\text{ Mbps} (1 Gigabit per second1\text{ Gigabit per second}).

    • Wired LAN speeds generally outperform WLAN speeds.

Advantages & Disadvantages of Networks

  • Network Advantages:

    • Shared hardware, software, and internet connections.

    • Centralized software updates and administrative security control.

    • Central internet monitoring via proxy servers.

  • Network Disadvantages:

    • High installation and maintenance costs.

    • Requires a network administrator for management.

    • Security risks to data if the network is compromised.

    • Server failure can prevent all users from accessing files.

  • Wireless-Specific Disadvantages:

    • Less secure transmission compared to physical cables.

    • Performance degrades as the number of connected devices increases.

    • Susceptible to signal loss and radio interference.

Network Security & Ethical Use

  • Network Security: Rules and tools designed to prevent unauthorized access and network abuse.

    • Authentication: Access controlled via unique usernames and passwords.

    • Strong Passwords: Minimum 8 characters combining uppercase, lowercase, numbers, and special symbols.

    • Passphrases: Multi-word combinations (e.g., 4 words, 15+ characters) offering high security while remaining easy to remember.

  • Acceptable Use Policy (AUP): Document defining allowable and prohibited user behaviors on an organization's network to safeguard users and infrastructure.

    • Key Contents: Netiquette guidelines, download/bandwidth limits, software/hardware installation restrictions, malware procedures, and policy violation consequences.

  • Throttling: ISP practice of intentionally slowing down internet speeds when users exceed fair usage data limits.