How are networks connected? | FusingBits Academy

The core idea

Connections create possibilities.

A network is more than a list of devices. Topology shows how those devices are connected, which routes traffic can take, and where a single broken link can interrupt communication.

The useful mental model is simple: topology is the shape of connectivity, not the application carried over it.

Separate shape from behavior.A star, mesh, or ring can carry many of the same messages. Their different paths change resilience, cost, and the work required to manage failures.

Use two views

Physical and logical topology answer different questions.

Physical topology describes the actual connections: cables, radio links, ports, switches, and the locations where equipment is installed. Logical topology describes how traffic is organized and which path or shared medium carries communication, even when the physical wiring looks different.

Token Ring is a network technology that uses a token to control which device may transmit. It traditionally presents a one-way logical ring, but its physical wiring can use a central MAU that looks like a star. Therefore, Token Ring is an implementation that can use a ring logically, not another name for every ring topology.

PHYSICAL

What is connected?

Which interfaces and links exist, and where is the equipment?

LOGICAL

How can traffic travel?

Which forwarding, sharing, or segmentation rules determine reachability?

EXAMPLE

Ethernet star

Many cables may meet at one switch, while the switch forwards separate conversations between selected ports.

One network can have more than one useful topology description.A Wi-Fi network may look like a star around an access point physically, while its shared radio medium creates different logical contention and failure behavior.

Build the model

Five useful shapes

01

Star

Devices meet at a central switch. It is easy to extend, but the center is important.

02

Mesh

Devices have multiple possible paths. Redundancy improves resilience but adds links and complexity.

03

Ring

Each device connects to neighbors around a loop. Traffic can follow the ring, but a break needs a recovery strategy.

04

Bus

Devices share one backbone. It uses less cabling, but a backbone fault can affect every connected device.

Do not confuse Ring with Token Ring.Ring describes a network topology: devices form a loop. Token Ring describes a specific token-passing technology that traditionally uses a one-way logical ring. A ring topology does not automatically mean Token Ring.

A double ring adds a second loop.Two separate rings provide an alternate path when one link or ring fails. This is different from a single bidirectional ring: bidirectional traffic can use two directions, while a double ring adds a second physical or logical loop for resilience.

A bus is a shared medium.Devices contend for the same backbone, so simultaneous transmissions need an access rule. The backbone also needs proper termination at its ends to prevent signal reflections.

Compare the failure model

TopologyStrengthMain weakness

StarEasy to extendCentral device is critical

MeshSeveral alternate pathsMore links and complexity

RingPredictable loopBreak needs recovery

Double ringSecond loop for resilienceMore cabling and equipment

BusLess cablingShared backbone is critical

Set the boundary

PAN, LAN, MAN, WAN, and SAN describe scope or purpose.

PAN means Personal Area Network. It connects devices around one person over a very short range, often with Bluetooth, USB, or another personal link. A phone connected to wireless earbuds or a smartwatch is a typical PAN.

LAN means Local Area Network. It is a network operated across a limited place such as a home, office, school, or campus building. Ethernet and Wi-Fi links, switches, and local addresses commonly work together inside a LAN.

MAN means Metropolitan Area Network. It connects multiple LANs across a city or metropolitan area, usually through infrastructure managed by an organization or provider.

SAN means Storage Area Network. It is a dedicated high-speed network that gives servers controlled access to shared storage, commonly using Fibre Channel or storage protocols over Ethernet.

PERSONAL AREA NETWORK PAN

A short-range network around one person, connecting personal devices directly or through a small personal hub.

Example: a phone connected to wireless earbuds over Bluetooth.

Scope is not topology, and SAN is purpose-specific.PAN, LAN, MAN, and WAN describe geographic or administrative reach. A SAN describes a specialized storage access role and can be built over different underlying network technologies.

Mini experiment

Break one link

Choose a topology, then simulate one failed link. Notice whether another path remains.

Star selected. Advantage: simple to extend and troubleshoot. Trade-off: the central switch is a critical shared path. Press “Break one link” to trace the result.

The diagram shows a star: devices connect through switch SW.

Knowledge check

Test your topology model

Answer fifteen questions. The answer order changes each time.

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