protected void onAcknowledge(Acknowledgement acknowledgement)
{
try
{
waitForAckLatch.Get().CountDown();
waitForSeqAckLatch.Get().CountDown();
CongestionControl cc = session.getCongestionControl();
long rtt = acknowledgement.getRoundTripTime();
if (rtt > 0)
{
long rttVar = acknowledgement.getRoundTripTimeVar();
cc.setRTT(rtt, rttVar);
statistics.setRTT(rtt, rttVar);
}
long rate = acknowledgement.getPacketReceiveRate();
if (rate > 0)
{
long linkCapacity = acknowledgement.getEstimatedLinkCapacity();
cc.updatePacketArrivalRate(rate, linkCapacity);
statistics.setPacketArrivalRate(cc.getPacketArrivalRate(), cc.getEstimatedLinkCapacity());
}
long ackNumber = acknowledgement.getAckNumber();
cc.onACK(ackNumber);
statistics.setCongestionWindowSize((long)cc.getCongestionWindowSize());
//need to remove all sequence numbers up the ack number from the sendBuffer
bool removed = false;
for (long s = lastAckSequenceNumber; s < ackNumber; s++)
{
lock (sendLock)
{
removed = sendBuffer.Remove(s);
}
if (removed)
{
unacknowledged.DecrementAndGet();
}
}
lastAckSequenceNumber = (int)Math.Max(lastAckSequenceNumber, ackNumber);
//send ACK2 packet to the receiver
sendAck2(ackNumber);
statistics.incNumberOfACKReceived();
if (storeStatistics)
{
statistics.storeParameters();
}
}
catch (Exception ex)
{
Log.Write(this.ToString(), ex);
}
}
/**
* spec p. 13: <br/>
* 1) Locate the related ACK in the ACK History Window according to the
* ACK sequence number in this ACK2. <br/>
* 2) Update the largest ACK number ever been acknowledged. <br/>
* 3) Calculate new rtt according to the ACK2 arrival time and the ACK
* departure time, and update the RTT value as: RTT = (RTT * 7 +
* rtt) / 8. <br/>
* 4) Update RTTVar by: RTTVar = (RTTVar * 3 + abs(RTT - rtt)) / 4. <br/>
* 5) Update both ACK and NAK period to 4 * RTT + RTTVar + SYN. <br/>
*/
protected void onAck2PacketReceived(Acknowledgment2 ack2)
{
AckHistoryEntry entry = ackHistoryWindow.getEntry(ack2.getAckSequenceNumber());
if (entry != null)
{
long ackNumber = entry.getAckNumber();
largestAcknowledgedAckNumber = (int)Math.Max(ackNumber, largestAcknowledgedAckNumber);
long rtt = entry.getAge();
if (roundTripTime > 0)
{
roundTripTime = (roundTripTime * 7 + rtt) / 8;
}
else
{
roundTripTime = rtt;
}
roundTripTimeVar = (roundTripTimeVar * 3 + Math.Abs(roundTripTimeVar - rtt)) / 4;
ackTimerInterval = 4 * roundTripTime + roundTripTimeVar + Util.getSYNTime();
nakTimerInterval = ackTimerInterval;
statistics.setRTT(roundTripTime, roundTripTimeVar);
}
}