A network is made of nodes and connections.
A network node sends or gets information. To do this, it needs an address. On the Internet[^en.wikipedia.org/wiki/Internet], this address is called an IP address and is based on the Internet protocol family[^en.wikipedia.org/wiki/Internet_protocol_suite], which uses the Internet protocol[^en.wikipedia.org/wiki/Internet_Protocol].
Some nodes do special tasks.
Within a network, the nodes know each other. An interface is necessary for communication with the outside. This task is performed by a router [^en.wikipedia.org/wiki/Router_(computing)].
Servers [^en.wikipedia.org/wiki/Server_(computing)] provide a service that is used by the client [^en.wikipedia.org/wiki/Client_(computing)]. A service is an application. The internet provides the platform for the use of the application.
- You connect your email client to an email server.
- A web browser is a client that uses the services of a web server to display a website.
- Social networks such as Twitter or Mastodon,
- e-commerce websites like Amazon or the little web shop of the Fair Trade Shop in your town,
- mobile apps like the weather app
are examples where a client and a server are involved.
In distributed peer-to-peer networks [^en.wikipedia.org/wiki/Peer-to-peer], this distribution of roles is cancelled. Each device has equal status and has the possibility to act as a server and as a client at the same time.
In a central network, one router takes over the routing. In a graphical illustration, this has the shape of a star.
A network is decentralised if it communicates with the help of many routers. A graphical visualisation shows many connected stars.
Computer-to-computer connections represent a distributed network when there is communication between equals. In pure peer-to-peer networks, all computers have equal rights. They take services and provide their own in return. In a graph, no hierarchy can be seen. All nodes are meshed with each other.
In a distributed network, everyone has equal status. In reality, we are seeing an increased centralisation of services on the internet.