This technique of temporarily delaying the acknowledgment so that it can be hooked with next outgoing data frame is known as piggybacking.
Piggybacking data is a bit different from sliding window protocols used in the OSI model.
If the counter ends without receiving confirmation, the sender assumes packet loss, and sends the frame again.
How long should the data link layer wait for a packet onto which to piggyback the acknowledgement?
If the data link layer waits longer than the sender’s timeout period, the frame will be retransmitted, defeating the whole purpose of having acknowledgements.