Random disconnect or crash

does anybody have random disconnects? my game freeze for like 5 sec and than disconnects.
this only happens on one client when i have opened 2. one will crash or disconnect and the other runs normal :S

edit:
just happend again. my iss dc but main char still online

 

make sure u have not turned on optimize performance in game option

 

don't have that on.
but i forgot to add l2 folder to ignore list of my av software and firewall.
we will see tomorrow D:

 

and again disconnected, this night on one account...

 

looks like it's a ISP issue. i am not the only person with connection problems. Deutsche Telekom ftw :/