Assume we have the cumulative acknowledgment protocol with unbounded sequence numbers. Assume the channel can lose and reorder messages (but not...

Assume we have the cumulative acknowledgment protocol with unbounded sequence numbers. Assume the channel can lose and reorder messages (but not duplicate). Furthermore, assume that the SWS = 1, and that the timeout of the sender is accurate,. i.e., the last action of the sender is replaced by

when timeout frame#ch.sender.receiver = 0 and ack#ch.receiver.sender = 0 and LAR < LFS then

     send frame(LAR+1) to receiver.

Under these conditions, is the sequence number in the acknowledgment really necessary? Briefly argue why yes or why no.