I really didn't like it (whatever version was current in 2004?ish), so I'd suggest Tanenbaum's Computer Networks. Not sure if it got updated in the last 15 year

I really didn't like it (whatever version was current in 2004?ish), so I'd suggest Tanenbaum's Computer Networks. Not sure if it got updated in the last 15 years, but the basics should still be there.