Defender, if this is a recent problem, we've been having some server issues lately that cause the server to crash.
If this is not a recent issue, OR if this is happening to you at regular intervals (as you said every 20 minutes), there's a good chance this is a problem with either your Computer, your Router or your ISP. This is especially true if you get disconnected, and can immediately reconnect within one minute.
I know that's a big range, but there can be specific settings in all of those areas that cause your problem.
A quick and easy way to check your computer is to run Winsock Fix -
http://www.softpedia.com/get/Tweak/Network-Tweak/WinSockFix.shtml which can automatically take care of issues with Windows and your network.
If that doesn't work, identify your connection type. If you're on a DSL or Cable Modem, try plugging your computer directly into the modem and see if that solves the problem. If that doesn't work, or if you have a different (school, work, etc.) connection there may be a connection issue, restriction, ip change, or idle limit that's causing you problems.
This is not an issue with Insurgency, so if you don't find your solution here, it'd probably be a good idea to post in our Tech Support forums -
http://edgegamers.org/forums/forumdisplay.php?f=379