A network is a collection of two or more devices connected by communication links so that they can communicate with each other and share resources and information. 

Some important terms related to networks are

• Bandwidth:

Network bandwidth is a measure that denotes the maximum capacity of a wired or wireless communication link to transmit data over a network. In other words, we can say that bandwidth measures how much data can be transmitted over a connection link in a given amount of time.

Bandwidth is usually measured in the number of bits, kilobytes, and gigabytes transmitted per second.

• Node:

In networking, nodes are connection points inside a network.

A node refers to an entity/device that is connected to a network and is capable of receiving, processing, and/or transmitting data in a network.

A few examples of nodes include computers, printers, modems, bridges, and switches.

• Link:

A link refers to the connection or medium by which two devices/nodes are connected in a network. The connection link can either be wired or wireless.

Wired connections are made using cables like an ethernet cable, coaxial cable, optical fibers, etc. 

Wireless connections are made without cables using air as a medium. Infrared, radio, microwave, and satellite are commonly used.