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tcp: Enable byte counting window growth for CUBIC slow start

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This commit is contained in:
Tom Henderson
2020-11-12 12:13:51 -08:00
parent 25da12ca64
commit 8ee3d4fec0
1 changed files with 10 additions and 2 deletions
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12
src/internet/model/tcp-cubic.cc
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@@ -172,8 +172,16 @@ TcpCubic::IncreaseWindow (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked)
HystartReset (tcb);
}
tcb->m_cWnd += tcb->m_segmentSize;
segmentsAcked -= 1;
// In Linux, the QUICKACK socket option enables the receiver to send
// immediate acks initially (during slow start) and then transition
// to delayed acks. ns-3 does not implement QUICKACK, and if ack
// counting instead of byte counting is used during slow start window
// growth, when TcpSocket::DelAckCount==2, then the slow start will
// not reach as large of an initial window as in Linux. Therefore,
// we can approximate the effect of QUICKACK by making this slow
// start phase perform Appropriate Byte Counting (RFC 3465)
tcb->m_cWnd += segmentsAcked * tcb->m_segmentSize;
segmentsAcked = 0;
NS_LOG_INFO ("In SlowStart, updated to cwnd " << tcb->m_cWnd <<
" ssthresh " << tcb->m_ssThresh);