The document describes the selective repeat ARQ protocol, highlighting a scenario where four frames (f0, f1, f2, f3) are sent to 'y', with f0 being lost during the first attempt but the other frames successfully transmitted. It specifies that the propagation delay is 1 time unit and the timeout is set at 8 time units, while the window size settings are both 2. The objective is to illustrate the complete frame exchange sequence until all frames are successfully delivered.

1. #9 - Selective Repeat ARQ Protocol
X attempts to send four frames (f0, f1, f2, f3) to Y. f0 is lost on the first attempted transmission,
and all other transmissions succeed. If the propagation delay is 1 time unit, the timeout for each
frame is 8 time units, and wr = ws = 2, complete the frame exchange sequence until all four
frames are delivered.