Moving past TCP in the data center, part 1

Oh, and the reasoning for this is that PHYs are expensive. Specifically, the optics are and the power needed for higher-end optics along with the thermal budget/constraints (the DC cabling is also a headache, but more minor). Fewer PHYs, fewer high-end transceivers == cheaper + lower-power, more efficient DCs. At the scales the really really big DC operators work at anyway.