provided by the udp protocol and must be included in the application which utilizes the present invention according to the preferred embodiment of the invention an acknowledgment is transmitted for each packet received however modifications can be made to this procedure such as transmitting acknowledgements for only a specified subset of the received packets such as every second packet or every third packet as illustrated in the discussion of fig1 according to the preferred embodiment of the invention the left edge of the window moves one packet to the right each time an acknowledgement is received and another packet is added to the window moving the right edge of the window one packet to the right to restore the window to its intended size all packets within the window and which have not already been transmitted are available for transmission as soon as the transmitting computer can do so if acknowledgements are transmitted for only a subset of the transmitted packets the procedures for moving the left and right edges of the window must be modified accordingly those procedures must also take account of potential packet loss u2014 if acknowledgment fails to arrive for a particular packet but acknowledgments are received for subsequent packets movements of the window edges must allow for the lost packet in addition if the application or transmission protocol in use creates data packets of different sizes the procedures can be modified to ensure that the window includes the correct amount of data which may mean a changing number of data packets the present invention differs.