To be honest, the fact that you have to ask, pretty much says that you won't understand the answer...
Protocols are not designed in any programming language: nor are they intended to be implemented in any specific programming language.
They are designed in English (or other natural languages) in generally massive documents, normally by large committees, or by interest groups, frequently starting one or other of the ISO 7 layer model.
That you ask this question does imply that you don't yet know enough about communications to even begin designing anything useful, let alone implementing it. Try something simpler for the moment - this is not a game for beginners!