If each data packet had to be acknowledged before another could be sent, then performance could suffer due to the delay time needed for the data packet to reach the receiver, plus the time needed for the acknowledgment packet to get back to the sender. To avoid this delay, the sender is allowed to keep transmitting data packets prior to receiving acknowledgments (Ack's) up to a maximum "window" size (RWIN) advertised by the receiver, normally large enough for several packets. The larger the window, the more packets that can be sent before needing an acknowledgment. However, larger windows can require more packets to be retransmitted when a transmission error occurs. Hence, the receive window size needs to be large enough to keep data flowing continuously, but it should not be excessively large.
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by Pinan  edited by JMGullett
last modified: 2007-02-21 16:27:40 |
