What sad news. Dave was an incredible human and very dedicated to making the Internet better and faster. What a loss.

Edit: copying over Vint Cerf's message that was posted on the bufferbloat mail list. I believe that's a public mail list so hopefully Vint doesn't mind:

OMG - that is truly terrible news! I could not say better than Frank already has how much Dave's work has helped to improve our experience of the Internet. I can't think of anyone more dedicated to the proposition that performance counts and should be pursued with determination and vigor. I've known Dave for many years and greatly valued his counsel and technical skills - to say nothing of his healthy sense of humor. I will miss him but will be always grateful to have known him.

dang, could we get a black bar?