Preparation for 4D recitation

This paper doesn't present an existing, real system. Instead, the author propose a design space for thinking about network architectures. They pick a particular design point in that space, which they term "4D", and discuss the advantages and disadvantages of this particular architecture. Finally, they lay out a research agenda for continuing to evaluate—and perhaps even implementing—4D.

As you read, think about the following:

Question for Recitation

Before you come to this recitation, write up (on paper) a brief answer to the following (really—we don't need more than a couple sentences for each question). If your TA has requested that you email your answer to them, you may do that instead, but it should still be handed in before your recitation begins.

Your answers to these questions should be in your own words, not direct quotations from the paper.

As always, there are multiple correct answers for each of these questions.