The following I can say with certainty:
Is affected: side channel
Is not affected: direct communication, group channel, vehicle channel
Not yet assured: global channel, command channel

Problem solved. At least in my case. GameSpy! When I opened all the ports, I have no more lag. No lag when connecting. No lag in game. Do not crash.

Here are the ports that I have entered in my router:
6667 (IRC)
3783 (Voice Chat Port)
27900 (Master Server UDP Heartbeat)
28900 (Master Server List Request)
29900 (GP Connection Manager)
29901 (GP Search Manager)
13139 (Custom UDP Pings)
6515 (Dplay UDP)
6500 (Query Port)

I'm spoiled by UPNP. It is long ago that I had to enable a port. Please find a better solution before you published the game. :-)

I am sorry. First time I use rapidshare. I moved the file in a shared folder. It should work now: http://rapidshare.com/files/1417564203/Arma%203%20Alpha.7z

Or this one: https://rapidshare.com/#users|46495817|e7a60766affea0d47f00d319853817f1|14461|referer-827D34FAB8112C243C92C9227128E1AB

I have exactly the same problem. The game freezes every 15-30 minutes short. Short means 5-30 seconds. After that it runs smoothly again or crashes completely. If it crashes it will freeze and then immediately displays the crash report. Here's my dxdiag.txt and the entire contents of my "Arma 3 folder" is. Apologies that I use no WinRAR. Have placed it with 7zip. That should not be a problem. Or? I am happy to assist you.

http://rapidshare.com/files/1417564203/Arma%203%20Alpha.7z

It seems you have a local problem. Some (virtual) device didnt work correctly. So you hear that sound. Maybe you have to take a look in your hardware devices or local errorlogs.

Same problem here. Happend allways after 5-30 minutes on every server I've connected. Internet connection allways working fine.

Same problem here.

Same Problem. Not testet in Escape from Statis yet.

http://rapidshare.com/files/1417564203/Arma%203%20Alpha.7z

No more freezes. Thanks for fixing this.

I have exactly the same problem. The game freezes every 15-30 minutes short. Short means 5-30 seconds. After that it runs smoothly again or crashes completely. Can't reproduce it. Some time it happens without any reason.

Problem solved. At least in my case. GameSpy! When I opened all the ports, I have no more lag. No lag when connecting. No lag in game. Do not crash.

Here are the ports that I have entered in my router:
6667 (IRC)
3783 (Voice Chat Port)
27900 (Master Server UDP Heartbeat)
28900 (Master Server List Request)
29900 (GP Connection Manager)
29901 (GP Search Manager)
13139 (Custom UDP Pings)
6515 (Dplay UDP)
6500 (Query Port)

I'm spoiled by UPNP. It is long ago that I had to enable a port. Please find a better solution before you published the game. :-)