Author Topic: Weird Multiplayer connectivity issues  (Read 1874 times)

Offline Simberto

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Weird Multiplayer connectivity issues
« on: June 10, 2015, 05:06:58 PM »
Hello.

As stated above, a friend and I have some weird connection issues. We may be in a pretty unusual situation, too, as i have a DS-Lite internet connection, which means i don't have a real IPv4 adress, and thus cannot reasonably use post forwarding to host since afaik AI War only understands IPv4 addresses.

My friend is in a student home on a university network, which leads to absurd amounts of other complications. and also means he is not able to influence his router settings in any way.

Despite all of this, we have managed to get the lobby to work through Hamachi after some effort. Sadly, that is about all that works, as when we start the game, the person who is not hosting manages to load between the first 1.5-9.5% in the first half second of loading while the host is in the game staring at the "waiting for player" message. Then the loading just stops at that percentage for about a minute or two, at which point we get a "connection failed" error message and are thrown back into the main menu.

I have tried both the version of AI War that i own on the humble store, and the one i own on steam, while he used the one he just bought of GoG mainly to play coop together. The result is always the same.

Offline x4000

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Re: Weird Multiplayer connectivity issues
« Reply #1 on: June 10, 2015, 05:30:17 PM »
Hey there, sorry to hear about the trouble.  Most likely the problem in this case is that one of the network adapters or routers is getting flooded with data and rather than buffering it is just dying.  There are two ways to fix this:

1. On the host mainly, but also on the client if you want, you can lower the Maximum Transmission Unit (MTU) in the Game settings from 1400 to 1200 or even 1000.  If you are having ongoing stuttering during play, then probably what is happening is that your packets are larger than the maximum packet size on some router between the two of you, and so those packets are getting subdivided further, and then not getting put back together properly sometimes, leading to transmission delays, etc.  That's not the core problem you're having right now, probably, though, but it's a good thing to know given your current issue.

2. Your main problem right now is based around the amount of data that is being sent across the network in one big batch.  That's either flooding the TCP stack improperly (driver bug), or causing some other form of backup somewhere along the line, so it stalls out with just lots of resends and so forth.  The way that I put in to get around that is making it so that during these giant data transfers for when you're first syncing a game (either from a loaded state or starting a new game after a lobby -- no other part of the game) is the Network Sync Size on the Game settings tab.  The default is N/1200, but clearly that's not working out for you.  You might try N/2400 and see if that works, and N/400 if that doesn't, and see if that does.  I think it's the latter that will actually do it, but my memory is hazy.

Hope that helps!
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Offline Simberto

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Re: Weird Multiplayer connectivity issues
« Reply #2 on: June 10, 2015, 05:49:09 PM »
Thanks for the quick answer, we will try those settings out the next time we try for a game.

There is pretty much 0 chance i would have ever found those on my own.

Offline x4000

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Re: Weird Multiplayer connectivity issues
« Reply #3 on: June 10, 2015, 06:59:26 PM »
Glad I could help!  The wiki for the game does have a writeup on that stuff IIRC, or at least it should.  But yeah.  The problem doesn't come up super frequently, but actually it's often college campuses that have a strange MTU setting in particular.  No idea why!
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Offline Simberto

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Re: Weird Multiplayer connectivity issues
« Reply #4 on: June 12, 2015, 05:29:55 PM »
Ok, we have tried that, and it doesn't work. We both changed MTU to 1000, and both changed the N/1200 once to N/400, which didn't work, and once to N/2400, which also didn't work.

We were, however, able to play Terraria over that exact same Hamachi connection.
« Last Edit: June 12, 2015, 05:31:31 PM by Simberto »

Offline x4000

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Re: Weird Multiplayer connectivity issues
« Reply #5 on: June 12, 2015, 07:09:34 PM »
Hmm, I'm not sure what to say with that.  Terraria does have a lot less data that it's trying to send, that is one thing.  Once the games are loaded they send similar amounts, but AI War has to send more upfront.

One thing to try is updating your network drivers just in case, because I have seen that be a problem before.  Beyond that, Hamachi is actually kind of a sub-par VPN option these days from what I've heard.  There have been a variety of alternative suggestions that people have had here and elsewhere over the years for things that worked better for them with games in general -- easier to connect, less latency, etc.
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