Understanding Computer Networks: LAN, WAN, Topologies & Protocols

Posted on Mar 13, 2025 in Computer Engineering

Understanding Computer Networks

Network Types

  • LAN (Local Area Network): Limited geographically, greater capacity, higher transmission speeds, lower error rate.
  • WAN (Wide Area Network): Wide geographical area, lower capacity, higher error rate.

Other Network Types

  • Metropolitan (MAN)
  • Personal Area (PAN)
  • Wireless LAN (WLAN)

MAN (Metropolitan Area Network)

Limited to areas like a city population.

PAN (Personal Area Network)

Home networks are simple and small, using wireless or cable connections, with small costs.

WLAN (Wireless LAN)

  • Transmission medium: air (radio waves, satellite).
  • No wiring needed.
  • They are less secure than LANs.
  • Prone to congestion.

LAN Features

Transmission: Multiaccess

Access from multiple computers to a common information source. A computer can access various sites.

Communication: Multipoint

Multipoint Network. Each data channel can communicate with different modes (HOST). Just one communication line is shared with all network terminals.

Network Topology

Topology defines how the network is distributed, including equipment location and type of wiring.

Types of Topologies

  • Star
  • Ring
  • Bus

Other Topologies

  • Mesh
  • Tree
  • Total Interconnection
  • Mixed
Star Topology

The host computer connects to a central node (hub). The Hub allows equipment segments to intercommunicate and isolate problems. If a network segment is broken, the rest of the network continues to function, providing security.

Network Standards

Standards set requirements for equipment. Manufacturers can follow these rules or create their own. Mandatory standards are set by state laws.

Types of Standards

  • De facto: Standard accepted in the market for widespread use.
  • De jure: IEEE Standard established that the manufacturer intends to use these rules and design their equipment accordingly.
Ring Topology

The computers are connected in a ring. If a segment breaks, the network fails. There is traffic congestion.

Bus Topology

The computers are connected to a linear structure. If there is breakage in some segments, the network fails. Multiaccess-Bus establishes rights for stations to access resources.

Token Ring

Physical star topology, but logically works as a ring. A team sends information. There is a token traveling around the ring. If a team wants to send information, it waits until it gets the token, puts the information, and sends it to another computer.

Network Protocols

A set of organized and agreed-upon rules that allow communication between different nodes or computers. The networks are structured according to function and services offered by the layers. The layers are layered, and each layer offers its services to the layer above it. The interface layers are a set of standards that enable communication between layers.

Network Architecture

A set of layers and network protocols that enable communication between different computers.

Interoperability

Two teams are interoperable if they can work with each other but are from different manufacturers.

Open Systems

A set of computers, peripherals, streaming media, and associated software that enables communication between them.

Topology Comparison

Bus Topology

  • Has a unique communication channel.
  • One-way communication.
  • The cable is bounded by terminators.
  • Easy to install, economical, and simple.
  • Prone to traffic jams.
  • A break in the network segment overrides the network.
  • Limited channel lengths.
  • Easy growth, but signal degradation occurs.
  • Quick.

Ring Topology

  • The nodes are connected in a ring.
  • Uses a token.
  • Less quick than the bus.
  • A failure or breakage in a segment invalidates the network node.
  • Easy to deploy and grow.
  • Limited channel lengths.
  • Slow data transfer.

Star Topology

  • The nodes or stations are connected to a central point.
  • If any node or segment breaks or fails, the network continues to function.
  • More secure, avoids traffic problems or crashes.
  • Maintenance is easier and cheaper.
  • If the central node fails, the whole network fails.
  • Its implementation is more expensive due to more cables and hubs.

Components of a Local Network

  • Server: You can have more than one.
  • Workstations, or HOST.
  • Gateways/Routers/Hubs/Switches.
  • Cables: Coaxial cable or optical fiber.
  • Network application software.
  • Network Operating Systems.
  • Rosettes, RJ45 connectors.
  • Protocols.