One example we did in class has the following information:
SWS = 3
LAR = 5
LSS = 7
And we said that the sender would send 8 now. However, since it only has acknowledgement for up to 5, does the sender resend 6,7 and send 8 too?
I believe the sender would only re-send 6 after a certain "timeout period" had expired, at which point it has given up on receiving the ACK for 6. In the meantime, it can happily send #8.