HTML5 sub nav semantics

Question

A quick question re: HTML5 nav, specifically that of sub navigation (from a semantic point of view).

I have

in the header for the main menu. Dow

Answer 1

I would differentiate between the navigation sections by giving them semantically relevant ids and by placing them in order of importance in the HTML code, along the following lines:

Other than that, I see no real need for further differentiation between the sections. The above approach is easy to understand, should be reasonably easy to style and is semantically clear, which is certainly good enough for me.