Q & A on Reasons for Limits on Ethernet Frame Size Q: 1. Explain the technological reasons for the minimum and maximum frame sizes in Ethernet LAN A: The minimum size makes it possible to distinguish a frame from noise; the maximum size guarantees fair access (if one station could send an arbitrary amount of data in a frame, other stations would need to wait an arbitrary time). Q: 2. Explain why lost TCP acknowledgment segment don't necessary force retransmission of data segment (losing the ack for segment 5 may not result in segment 5 being transmitted) A: TCP uses cumulative acknowledgements. Thus, if the ACK for the 5th segment is lost, when the 6th segment arrives, the ACK will cover *all* the data up through the 6th segment, which includes data from the 5th segment.