Since the netcode in SFV has been coming up as a hot topic again, I thought I ought to make a post to reference this, as this information is very hard to find.
Here are the ports we found worked for helping improve online play on SFV. The problem is there is a lot of other information out there that didn’t seem to work (even from official sources). The source of this was from the organisers of the Gfinity online SFV tournaments (sadly from a chat room, so I cannot show the exact source link) specifically to help players to connect to each other better, especially on cross-play. Note that the ports you want to forward are different for PC and PS4:
Here are the ports we found worked for helping improve online play on SFV.
UDP: 3478, 4379-4380, 27000-27031, 27036
TCP: 80, 443, 1935, 3478-3480
Background info: I’ve tested this playing SFV vs nearby players and found that this does make a difference. For example, vs one player in my city, PC vs PS4, we always had perfect matches. Vs another player in my city, PC vs PS4, or PC vs PC, we had a slide-show almost every time, until he put his PC or PS4 into a DMZ, and then it was fine, which proved it was a router issue. And finally figuring out these ports correct ports for PC and PS4 fixed the problem, and now we can play fine always too.
I think a lot of your home router & ISP setup is why some people experience pretty good experiences online, whereas others get a horrible time. Of course the game SHOULD have been coded much better to deal with the realities of today’s home internet setups in the majority of countries, so I’m not excusing it fully here, just saying this definitely does matter. It should also help with matchmaking as you will now have a higher “bar” to more other players. It may even help you get connected to nearby players more often. Of course it won’t fix every problem at all, and there can still be one-sided rollback.
I also believe there’s a problem, especially on the PS4, with SFV getting frameskips on certain stages, especially when certain moves are happening, and that this can also cause issues with additional rollback when playing online. I also suspect the AE update caused more of these performance issues on PS4 (and lower performance PCs of course) which may explain the reports of people having a worse experience since the AE release.