Abstract: A method and apparatus for providing for segmentation, reassembly and inverse multiplexing of variable sized packets and ATM cells over satellite and wireless links. Variable sized packets are divided into segments having a size equal to that of an ATM cell and are arranged in a segmentation and reassembly (SAR) frame having in its overhead an indication as to the length and unique identity of the frame, each segment also having a header that uniquely identifies the segment, the destination and the origination of the packet from which the segment originates. A terminal id is also used to identify the unit, site and control group from which the segment originates so that the information can be transmitted on the basis of available bandwidth on demand.