There is no loss of en-route air traffic control. Part of a
statement from MAS:
Malaysia Airlines confirms it received notification from Ukrainian ATC that it had lost contact with flight MH17 at 1415 (GMT) at 30km from Tamak waypoint, approximately 50km from the Russia-Ukraine border.
If there was a break in ATC coverage then it was probably related to lower airspace. MH and SQ have been routinely flying this airspace up until today. They haven't done anything wrong.