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Network topology

technology Maturity 11-13 Next article →

Network topology is the specific arrangement of elements within a communication network. These elements include nodes, which are connection points, and links, which are the connections between them.

NetworkTopologies
NetworkTopologies

This concept applies to many different systems. It can describe computer networks, industrial fieldbusses, or command and control radio networks. Scientists use graph theory to model these systems. In this mathematical model, communicating devices act as nodes. The connections between those devices are modeled as links or lines.

BusNetwork
BusNetwork

Understanding topology is essential for designing how information moves across the world.

There are two distinct ways to categorize network topology: physical and logical. Physical topology refers to the actual placement of components. This includes where devices are located and how cables are installed.

StarNetwork
StarNetwork

It is a primary concern of the physical layer of the OSI model. Logical topology, however, describes how data actually flows through the network. The logical path of information does not have to match the physical wiring. For example, a network might use a physical star topology. Yet, the data might move in a logical bus topology.

RingNetwork
RingNetwork

This distinction allows engineers to separate the hardware layout from the data movement rules.

Physical topologies come in several common shapes. In a local area network (LAN), nodes can be arranged in a ring, bus, mesh, or star.

NetworkTopology-Mesh
NetworkTopology-Mesh

A bus topology uses a single line to connect all devices. A star topology connects every node to a central point. A ring topology connects nodes in a continuous loop. Mesh topologies involve many interconnected links. Some systems, like Controller Area Networks in vehicles, use a physical bus topology. These networks connect controllers to sensors and actuators. The choice of topology depends on cost, control, and fault tolerance.

Links are the transmission media used to connect nodes. These media can be electrical cables, optical fibers, or radio waves.

Fibreoptic
Fibreoptic

Wired technologies include Ethernet, which is a widely adopted family of LAN technology. Ethernet can use copper or fiber cables. Twisted-pair cabling is the most common medium for telecommunications. It uses copper wires twisted into pairs to reduce crosstalk and electromagnetic induction.

Wireless network
Wireless network

Coaxial cable is another wired option, often used for cable television. It consists of a conductor surrounded by insulation and a conductive layer. These cables can reach speeds of over 500 million bits per second.

Optical fiber represents a much faster way to transmit data. An optical fiber is a thin glass thread. It carries pulses of light to represent data.

World map of submarine cables
World map of submarine cables

These fibers have very low transmission loss. They are also immune to electrical interference. Optical fibers can carry multiple wavelengths of light at once. This allows for data rates of up to trillions of bits per second. Because of this speed, they are used in undersea cables to connect continents. Wireless technologies offer a different kind of connectivity. These include terrestrial microwaves, which require line-of-sight, and communications satellites in geostationary orbit.

Wireless network
Wireless network

Satellites use microwave radio waves to relay voice, data, and TV signals.

Nodes serve as the connection points for these transmission media. A node is where the medium meets a transmitter or receiver.

ForeRunnerLE 25 ATM Network Interface (1)
ForeRunnerLE 25 ATM Network Interface (1)

While nodes are often computers, they can also be simple microcontrollers. Some nodes are designed to only transmit, while others can both transmit and receive. In a simple point-to-point topology, one transmitter connects to one receiver. In more complex systems, a single node might connect to many others on a single bus. Modern hardware like network interface controllers (NICs) helps manage these connections. These devices allow a computer to join a network and communicate effectively.

Topology connects to many broader scientific and engineering fields. It is deeply tied to media access control methods and protocols. Some advanced networks can even change their logical topology dynamically. This happens through configuration changes in routers and switches. The study of topology also touches on the OSI model, which organizes how different layers of communication work together. From the small scale of a printed circuit board to the massive scale of the interplanetary internet, topology defines the structure of our connected world.

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🖼️ Images & Media (11)
File:NetworkTopologies.svg
NetworkTopologies.svg
File:Fibreoptic.jpg
Fibreoptic.jpg
File:World map of submarine cables.png
World map of submarine cables.png
File:Wireless network.jpg
Wireless network.jpg
File:ForeRunnerLE 25 ATM Network Interface (1).jpg
ForeRunnerLE 25 ATM Network Interface (1).jpg
File:Adsl connections.jpg
Adsl connections.jpg
File:BusNetwork.svg
BusNetwork.svg
File:StarNetwork.svg
StarNetwork.svg
File:RingNetwork.svg
RingNetwork.svg
File:NetworkTopology-FullyConnected.png
NetworkTopology-FullyConnected.png
File:NetworkTopology-Mesh.svg
NetworkTopology-Mesh.svg
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