Network
A network is two or more nodes that are able to connect via a communication system and are able to share data.
A node is any device or connection point that participates in a network by sending, receiving, processing, or forwarding data.
As a simple mental model, you can also treat each external API as a node in a system diagram because each API represents a separate service with which your application communicates.
Why network mastery is fundamental for web developers
Mastering networking is essential for web developers because every web application depends on machine-to-machine communication. A user’s phone or computer must communicate with web servers, databases, cloud services, payment platforms, authentication systems, and other devices through a network.
Understand where failures happen and how to troubleshoot them.
Make sense of latency, bandwidth, caching, CDNs, and infrastructure choices.
Apply better controls to traffic flows, exposed services, and user access.
Connect browsers, APIs, databases, gateways, and IoT systems more effectively.
Classification of networks — STATA
One useful way to classify networks is with STATA:
Size
| Network type | Full name | Typical coverage | Example |
|---|---|---|---|
| BAN | Body Area Network | On or around one person | Smartwatch communicating with a heart-rate sensor |
| PAN | Personal Area Network | About 1–10 metres | Phone connected to earbuds or a smartwatch |
| LAN | Local Area Network | One room, home, office or building | Computers connected through an office router |
| CAN | Campus Area Network | Several nearby buildings | University, hospital or business campus network |
| MAN | Metropolitan Area Network | A town or city | A municipal fibre network |
| WAN | Wide Area Network | Countries or continents | A company network connecting branches in different provinces |
| GAN | Global Area Network | Worldwide | The internet or a worldwide satellite network |
Topology
Network topology helps web developers understand how systems connect, locate failures, improve reliability and performance, apply security, work with infrastructure such as load balancers and CDNs, connect IoT devices, and troubleshoot network problems.
| Topology | Structure | Common example |
|---|---|---|
| Point-to-point | One device connects directly to another | Computer connected directly to a printer |
| Point-to-multipoint | One central device communicates with several devices | Wi-Fi access point serving many phones |
| Bus | All devices share one main communication cable | Older Ethernet networks |
| Star | Every device connects to one central hub or switch | Most modern office Ethernet networks |
| Ring | Each device connects to two neighbouring devices, forming a circle | Some industrial and older network systems |
| Mesh | Devices connect to several other devices | Zigbee, Thread and wireless mesh systems |
| Tree | Several star networks are connected hierarchically | Large school or company network |
| Hybrid | A combination of two or more topologies | A business network using star, mesh and point-to-point connections |
Accessibility
A network or service that is openly reachable by authorised users from the wider internet or public communication environment.
A network restricted to a home, organisation, campus, or other controlled group of users and devices.
Architecture
| Architecture | Description | Example |
|---|---|---|
| Client–server | Clients request services from a central server | Website, email system, banking app |
| Peer-to-peer (P2P) | Devices communicate directly and can both provide and request resources | Direct file sharing between computers |
| Hybrid architecture | Combines client–server and peer-to-peer communication | Messaging or gaming system using servers plus direct device connections |
Transmission medium
Wired media include Ethernet, fibre optic cable, serial cable, coaxial cable, and USB cable.
Non-wired communication uses the electromagnetic spectrum. Many technologies have been created to take advantage of different parts of that spectrum.
INTERACTIVE LEARNING TOOL
Electromagnetic-wave simulation
Adjust the wave and material controls to see how the electric field, magnetic field, wavelength, direction, refraction and attenuation change during transmission.
This is a conceptual teaching model rather than a scale measurement tool. It is inspired by the interaction patterns of EMANIM and is implemented independently for the Optiact network guide.
| Technology | Typical electromagnetic spectrum | Energy use | Typical coverage | Data-carrying capability |
|---|---|---|---|---|
| Wi-Fi | 2.4 GHz, 5 GHz and newer 6 GHz bands | Medium–high | About 20–50 m indoors; 100 m or more outdoors | Very high: tens of Mb/s to multiple Gb/s |
| Bluetooth Classic | 2.400–2.4835 GHz | Low–medium | Usually 10–100 m | Medium: gross radio rates of 1–3 Mb/s |
| Bluetooth LE | 2.400–2.4835 GHz | Very low | Usually 10–100 m; specialised long-range designs can go farther | Low–medium: 125 kb/s to 2 Mb/s |
| LoRa | Regional sub-GHz bands; commonly 433, 868 or 915 MHz | Very low | Approximately 2–5 km urban and up to around 15 km rural | Very low: normally less than 50 kb/s |
| LoRaWAN | Uses the same regional LoRa bands; South Africa commonly uses 863–870 MHz | Very low | Approximately 2–5 km urban and up to around 15 km rural | Very low: roughly 0.3–50 kb/s |
| Zigbee | Mainly 2.4 GHz; some versions use 868 or 915 MHz | Very low | Roughly 10–100 m per connection; mesh devices extend coverage | Low: commonly up to 250 kb/s at 2.4 GHz |
| Thread | 2.4 GHz | Very low | Similar to Zigbee per connection; mesh covers a home or building | Low: 250 kb/s radio rate |
| RFID—LF | Around 125–134 kHz | Passive tag: no battery; reader: medium | A few centimetres | Very low: identification numbers and small records |
| RFID—HF | 13.56 MHz | Passive tag: no battery; reader: medium | Centimetres to about 1 m, depending on system | Low: identifiers and small amounts of stored data |
| RFID—UHF | Usually around 860–960 MHz | Passive tag: no battery; reader: medium–high | Approximately 1–10 m | Low–medium: rapid identification of many tags |
| NFC (RFID-HF) | 13.56 MHz | Passive tag: no battery; reader: low–medium | Usually within 2 cm | Low: approximately 46 kb/s to 1.7 Mb/s depending on mode |
| LTE—4G | Licensed cellular bands, commonly from below 1 GHz to around 2.6 GHz | High compared with BLE or LoRa | Around 1–10 km per tower; farther with low-frequency rural cells | High: commonly tens of Mb/s; theoretical single-carrier rates can reach about 75–150 Mb/s |
| 5G cellular | Low-band, mid-band and high-frequency millimetre-wave bands | High | Hundreds of metres to many kilometres depending on band | Very high: hundreds of Mb/s to multi-Gb/s |
| LTE-M | Licensed LTE cellular bands | Low–medium | Several kilometres; can use existing mobile coverage | Medium: suitable for trackers, meters and IoT devices |
| NB-IoT | Licensed cellular bands, often within LTE spectrum | Low | Several kilometres with strong indoor penetration | Low: sensor readings, meters and small messages |
| Infrared remote | Infrared light, commonly near 940 nm | Very low | Usually 5–10 m with line of sight | Very low: simple commands such as volume or power |
| GPS/GNSS | GPS examples include L1 at 1575.42 MHz, L2 at 1227.60 MHz and L5 at 1176.45 MHz | Low–medium receiver power | Global wherever satellites are visible | Not normal user-data communication: satellites transmit timing and navigation information |
Three main layers in spectrum-based communication technologies
The antenna, transmitter, receiver, radio chip, and other physical components that generate or detect electromagnetic signals.
The embedded software that controls the hardware and follows communication rules such as Bluetooth, Wi-Fi, Zigbee, or LoRaWAN.
An API, SDK, driver, operating-system service, serial interface, or gateway that allows an application to send commands and exchange data with the communication system.