4.0.1, Pre Cataclysm patch

Found the problem of my lag, and of almost everyone else:

After finally looking into this, I noticed that the game data switched back over to using TCP this patch, and I /palmfaced. No wonder there are issues! Also, this explains too why some peoples issues were resolved, such as at some college campuses.

Any chance you could put in a request to allow users to switch between the two protocols (TCP and UDP) at the very least via a line in the Variables.txt file? Honestly, sometimes one is better depending on the user. The default should really be UDP, though, for the sake of the Aussies.

blizzard response:

Maged: There are internal discussions about TCP vs. UDP, and the pros and cons of each, obviously I'll toss the idea of a user-selectable option into the mix, and see what happens...

That said, they should (theoretically) be roughly equivalent in performance, barring someone being on a very lossy link.

We're also trying to sort out exactly what's going on, and so eliminating protocol as a variable is key.

Of course it's our job to fix it -- but we first need to make sure we know exactly what is wrong, so that we don't go stabbing in the dark (and breaking other things).

We can only test a finite number of variations in network configurations, and so there will naturally be some that crop up that cause us grief in one way or another.

Path MTU is an interesting find, as it's possible there is network gear "in the middle" that is ignoring the DF flag and potentially fragmenting and re-assembling data on its own -- and who knows if it's doing things properly? To be clear: I'm not saying that's "the" problem here, I'm merely offering an example.

We're still collecting and analyzing data, and I'm here now to hopefully get some back-and-forth with people actively having issues, so we can nail this problem down once and for all

I apologize to those who have been having (and continue to have) issues playing StarCraft 2. But I want to absolutely assure you that we have been working on things and will continue to work on them until they are solved.

http://us.battle.net/sc2/en/forum/topic/...200?page=2

Blizzard changed how the client reach the server, and now, some networks are experiencing problems handling too many TCP connections, that's why some dont have lag, and others do have. :/