Network2/Concept/Capacity

Suppose that Alice is trying to send messages to Bob over a noisy channel like a radio link.

No matter what sort of link they possess, there are only finitely many different messages that Bob might reliably receive from Alice within a single unit of time. This quantity is the capacity of their link.

Link capacity is typically expressed in bits per second or some unit derived therefrom like Mbps (mega-bits per second).