Networking Essentials – Basic Network Concepts

Definition & Core Characteristics of a Network

• Network = Group of interconnected systems

  • Purpose: sharing of resources & services (files, printers, Internet access).

  • Scale can range from a simple single-site setup (few PCs on $(copper\;wires)$) to a global mesh (e.g. Internet using satellites, fiber, microwave links, etc.).

  • Transports multiple data types: $\text{data}$, $\text{voice}$, $\text{video}$.

Motivations for Networking ("Why Network Your Computers?")

• Resource & Cost Efficiency

  • Centralised storage → easier backup, version control, security.

  • Shared high-speed peripherals (e.g. colour laser printer) reduce per-user cost.

• File Sharing

  • Any local file or entire shared directories can be exposed to the network.

  • Use of a file server gives a single authoritative repository for all users.

• Hardware Sharing

  • Local devices (CD/DVD, hard drives) can be exported over the LAN.

  • Network devices (high-capacity printers, plotters) become common utilities.

• Program / Application Sharing

  • Keep main application binaries on a dedicated application server.

  • Easier deployment: install once, run everywhere; quicker upgrades: patch only the server.

• User Communication

  • Text: e-mail, newsgroups.

  • Rich media: voice calls, video conferencing, image transfer – possible because all are converted into packets of $\text{data}$.

Classification of Networks

• ## LAN – Local Area Network

  • Interconnects devices inside a restricted geography (home, school, single office building, campus).

  • Equipment & administration are local – owner controls cabling, switches, access rules.

  • Dominant media/standards: Ethernet (wired) & Wi-Fi (wireless).

• ## WAN – Wide Area Network

  • Spans multiple geographic locations; effectively connects several LANs together.

  • Example scenario:

  • Office-$B$ at Bandar: $100$ computers form one LAN.

  • Office-$T$ at Tutong: own LAN.

  • Inter-office link (leased line, VPN, MPLS, Internet tunnel, etc.) bridges the two, producing a corporate WAN.

• ## MAN – Metropolitan Area Network

  • Operates within a single city or wider metropolis.

  • Connects multiple buildings/campuses across that city.

• ## WLAN – Wireless Local Area Network

  • Wireless counterpart of LAN.

  • Uses high-frequency radio (Wi-Fi, $2.4$ GHz / $5$ GHz, sometimes $6$ GHz); usually employs an access point (AP) for Internet uplink & roaming.

  • Advantages:

  • No physical cabling → flexibility, mobility.

  • Users can move freely inside the coverage cell (house, small office) while maintaining connectivity.

Practical & Organisational Implications

• Centralisation vs. Decentralisation: file/application servers centralise management but require robust uptime & security.

• Scalability: moving from LAN → MAN → WAN often introduces latency, bandwidth costs, and demands technologies like routing, QoS, VPNs.

• Security Considerations: larger networks expose more attack surfaces; authentication, encryption, segmentation become critical.

• Cost–Benefit: initial cabling/AP purchases vs. long-term savings via shared equipment and streamlined workflows.

Conceptual Links & Further Study Directions

• OSI & TCP/IP models – understand which layers handle physical media (e.g. Ethernet) vs. routing (e.g. IP) when scaling LAN to WAN.

• Client–Server & Peer-to-Peer paradigms – underpin file sharing and application hosting.

• Emerging Trends: SD-WAN, mesh Wi-Fi, IoT-driven WLAN expansions.