I know this might sound like a very amateur and stupid question but I don't understand the concepts of these protocols in the OSI model. Are they just code that gets invoked? Also where does this code reside? Is it put on every server machine that needs to conform to the protocol when you are designing the network?
I am reading a book and it states that:
For starters, the abstract objects that make up the layers of a network system are called protocols.
Each protocol defines two different interfaces. First, it defines a service interface to the other objects on the same computer that want to use its communication services.
An implementation of the HTTP protocol could support an operation to fetch a page of hypertext from a remote server.
So in the case of an HTTP protocol when a user hits enter after entering a URL on their browser, some code for the HTTP protocol which is stored on some server machine is being run?