Cabled connection between computers are based, nowadays, on ethernet cables and ethernet connections, technically named CAT5 cables and RJ45 plugs, which allow computer to intercommuncate at a maximal speed of 100Mb/s.

There are specific harware components (devices), which take care of network connections. These could be ethernet (wired) devices or wireless devices. Although wireless devices are very practical, there is the possibility that they loose some packages on their way to the Internet. For radio streaming it results preferrable to use cabled connections. Mostly our computers will not be connected directly to the Internet: some hardware device will be in between of our machine and the connection!

These machines redistibute a connection from one source to multiple clients: one cable goes in, more cables go out. While switches share the traffic and redistribute it only to the connected computer which the traffic is destinated to, hubs simply redistribuite data to all the machines connected, leaving to the computer itself the funcion of picking up only the data directed to itself.

A router is a computer networking device that forwards data packets across an Internetwork toward their destinations, through a process known as routing.

While routers implement the functions of a switch, they are not only "passive" machines, it is better to understand routers as "computers". A router, in fact, has an own operating system running, and is usually modem itself, managing the whole connection to the Internet: configuration variables needed to connect to an Internet Service Provider, own firewall and filter roules, own dhcp-server and many other functions. A router is, in fact, our gateway to the Internet, the bridge where all the traffic has to pass through.

A modem is a simple device which interacts between a connection and a computer, effectively encoding/decoding a digital data from/to a carrier signal (ex. electrical frequencies in telephone connections). The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.