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A major reason explicit congestion notification is not used is firewalls that block anything that isn't bog standard TCP or UDP. Some even ban odd combinations
by api 6y ago
A major reason explicit congestion notification is not used is firewalls that block anything that isn't bog standard TCP or UDP. Some even ban odd combinations of flags. There are enough of these to make ECN useless.
- toast0 6y agoA router that is willing to buffer 5 seconds worth of packets probably wasn't going to mark for congestion and drop either. Note also, Apple is using MP-TCP and ECN in iOS, and the world didn't stop. It might not work everywhere, and I don't praise Apple lightly, but there's a pretty clear path to using things like this. Send a syn with it enabled, wait a bit, and send one with it disabled. Keep track of networks where it doesn't work and stop trying it there. If you have leverage, yell at people to not do dumb things, otherwise, let them figure out why expensive things work better on their competetors' networks. You can't rely on being able to use these things, but you can use them for progressive enhancement.