QUIC improves on TCP stream windowing/reassembly in two ways: - as noted by another commenter, you can send multiple streams in a single connection, so a lost

QUIC improves on TCP stream windowing/reassembly in two ways: - as noted by another commenter, you can send multiple streams in a single connection, so a lost packet for one stream does not necessarily affect others. - QUIC sends ACK as a bitmap instead of a single number (TCP only sends the number of the highest continuous stream byte seen). Senders can see that one packet was lost, but that the packets following were successfully received. For long/fat pipes this prevents the sender from re-transmitting packets following the single lost packet.