Got pretty much the same issue here.
It usually happens after one hour of playing.
One of the following hapens:
Network conection is lost completly.
Arma and TS are working fine but anything else does not work (including other computers).
This happens on all computers that I have.
And it also seems that I can always ping outside servers just fine but not anything else (like loading the webpage located on that server). My ISP also did not detected any problems on the line.