Deep packet inspection (which must slow down the process of routing some) and subsequent queuing of disfavored packets (without which there is no point to DPI) must necessarily slow down the entire process. If by some magic it doesn’t it is only because it isn’t needed since there is so much excess capacity that its effects are negligible. In this version of the world DPI/personal prioritization “tiers” are merely another bogus marketing claim.

But, of course, this excess capacity world does not exist in practice. For most of us the internet is often congested. Occasionally in the backbone but most often in our middle or last mile. These are all—from top to bottom—shared architectures. My prioritization of Gaming conflicts with your prioritization of Video conflicts with the next neighbor’s prioritization of VOIP….and on. Putting DPI inspection into the mix will NECESSARILY slow down traffic in the aggregate just by its nature. When there are conflicting sets of individually chosen prioritization schemes it must, I think, result in a slower net overall. Yes, under such a neighbor vs neighbor regime that this imagines you’ll get better gaming, or Video, or VOIP if you pay the extra 20 bucks to network owner than if you didn’t…but quite possibly you’d get no better than if it such prioritization did not exist at all. And _certainly_ the overall speed of net transmission would be slowed.

This is a technology that contravenes what is (or perhaps only what should be) the central principle of the internet: “unfettered communication.” It can be considered an evil technology because it must necessarily fetter disfavored communications to be useful.