A method and apparatus for extending the sequence numbering range for a selective repeat transmission protocol is described. In accordance with one embodiment of the invention, data frames are transmitted including an eight-bit sequence number and a one-bit retransmit flag. The one bit retransmit flag indicates whether the frame is newly transmitted or retransmitted due to a failed first transmission. The transmit and receive systems each maintain a twelve-bit sequence number referred to as a "long sequence numbers" comprised of the eight-bit sequence number transmitted with each frame and a four-bit extension. The long sequence number is transmitted within control frames and the eight-bit sequence number is transmitted within the data frames.