Edit: This answer was posted in reply to the original version of Raphael's answer, parts of it has become obsolete since then because of the edits he has made to his answer.
I disagree with closing such questions as off-topic.
First, there aren't arbitrary convention (at least no more arbitrary than conventions in other parts of CS). These standards and conventions are very important in computer networks which are typically defined using RFCs (see this). These RFCs and standards defined in them are essential to computer networks and are part of CS.
In fact, it shouldn't be difficult to find computer networks tests which ask such questions. There are similar conventions in other parts of CS including theory. Conventions like this are part of CS.
Your opinion that it is not worth knowing is a very personal opinion and IMHO such opinions should not be the base of what is on-topic/off-topic. We never defined the scope as "things worth knowing", if the question is in computer science (and I believe it is) then it is on-topic and in scope.
(Obviously closing such questions can be closed for other reasons. E.g. in this case OP hasn't done his part in trying to answer his question since googling will easily lead to the wikipedia article which answers the question, and if we think the OP should at least google and check the relevant wikipedia article then we can close it as say not-constructive.)