A 'protocol' is a rather technical word. But it simply means an agreed method of doing something.
A 'network protocol' is the agreed method of communication to be used within the network. For example the network protocol for the internet is TCP/IP. As long as computers connected to the internet are using TCP/IP they should be able to exchange data.
Another common protocol in Ethernet - this is both a hardware specification and data exchange protocol. It is very common as it flexible enough to deal with many common data exchange situations e.g. an ethernet based control network for handling production machines within a factory.
There are many protocols, usually developed with a specific need in mind.
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: Network Protocol