[mbelshe]

The reason we didn't like the Upgrade header is because it requires yet-another-round-trip in the protocol. Round trips are expensive, and getting worse both for desktops and mobile. (average RTT is ~114ms to Google, which has pretty good global presence)

As for SCTP, I think applications generally drive progress better than OSes do. Certainly the OSes have had enough time to sort out SCTP, but they haven't done it, and the end-game is nowhere in sight. Until there is an app that showcases it, will it ever happen?

My recommendation is to first prove new protocols at the application layer (perhaps run SCTP over UDP just to grease the skids). When people are addicted to how much better the experience is (multihoming + concurrent streams), then the OSes will pull it into the kernel to make it more scalable.

What do you think?