looks like all of them.right now IB have no control over orders,sitting on market centers and off course simulated orders cannot be placed to exchanges..what are we talking about here anyway? on both sides(our and IB ) we have no data..how you expect your simulated orders triggered?
one thing i didn't understand-they have multiple facilities all over the world. where all those sophisticated reconnection abilities to connect for example to canada servers? or they all down? as far, as i remember those forced updates of TWS started couple years ago are attempts to deal with such event. looks like the problem is far from being solved..