The available jump routes can significantly hinder the movement of a side's forces. Certain star systems act as bottle-necks, and can be used by each side as a defensive front. Two of the stars do not allow refueling, so tankers are required to leave these sites. Ships (excepting fighters and missile boats) are allowed to move at sub-light speeds across the hex map, and so can move directly from star to star without following the jump routes. However the movement rate of these ships is only one hex per turn.