I wondered about that too. Not the case on my wired network. Perhaps its because many laptops were taken out of suspend and then hardly used, so session-initialization messages dominate. btw Thanks for actually addressing the point of the article.

30% is mDNS which is multicast presence notification -- iTunes sharing, Bonjour etc. Blame Apple.

it does seem a little high but so many other protocols also require a dns lookup. sometimes more than one

TCP probably uses larger packets so results are bit skewed imho