Wireless is a specialization of its own. Knowledge of networking
is required to know wireless... because wireless networking
branched off from wired networking. The concepts of wired
networking applies to wireless as well. You will learn about
wireless technologies in addition to networking technologies that
you already know.
Networking is also a specialization of its own. DNS, VPN (you will
learn it in wireless as well), routing, subnetting, etc... all fall
under networking. If you haven't finished your A+ book, I don't
suggest you go further.
A+ books cover a little on networking as well, get those concepts
before proceeding to networking. And I have to stress one thing -
know your binary, hex and decimal system well. They are needed for
networking. While you have tools for that... remember that if you
are setting a brand new network, there's no such thing as tools.
Everything is manual.
You are expected to know how to fix PCs (that means removing and
putting it back, troubleshooting them, etc), so to answer your last
question, yes. But you don't need to fiddle with the engineering
part of it. Although it's good to know.
