Matthew Toseland wrote: > I thought TCP acked an entire window at once, not individual packets?
Every packet triggers an ack, but because of cumulative acks it's not always possible for the sender to tell which packet arrived. If you send 10,11,12,13 and 10 is lost, you'll get three acks for 9 because 9 is the highest in-order packet received so far. From this you infer that 10 was lost and fast retransmit it, at which point you get an ack for 13. :-) Cheers, Michael
