From e1d2bd27e1baeedc190f39c3e6628b77aae12a14 Mon Sep 17 00:00:00 2001 From: Anh Nguyen Date: Mon, 18 Apr 2016 17:20:17 +0200 Subject: [PATCH] internet: added TCP Veno --- RELEASE_NOTES | 2 + examples/tcp/tcp-variants-comparison.cc | 9 +- src/internet/doc/tcp.rst | 31 +++ src/internet/model/tcp-veno.cc | 253 ++++++++++++++++++++++++ src/internet/model/tcp-veno.h | 175 ++++++++++++++++ src/internet/test/tcp-veno-test.cc | 220 +++++++++++++++++++++ src/internet/wscript | 3 + 7 files changed, 691 insertions(+), 2 deletions(-) create mode 100644 src/internet/model/tcp-veno.cc create mode 100644 src/internet/model/tcp-veno.h create mode 100644 src/internet/test/tcp-veno-test.cc diff --git a/RELEASE_NOTES b/RELEASE_NOTES index a7cc516b2..ef9547a79 100644 --- a/RELEASE_NOTES +++ b/RELEASE_NOTES @@ -24,11 +24,13 @@ New user-visible features ------------------------- - (internet) Added TCP Vegas congestion control algorithm - (internet) Added TCP Scalable congestion control algorithm +- (internet) Added TCP Veno congestion control algorithm Bugs fixed ---------- - Bug 2057 - ARP and Ndisc caches should be updated by receiving valid L3 packets - Bug 2346 - SixLowPan ConpressionThreshold can be violated. +- Bug 2329 - TCP Veno implementation - Bug 2333 - TCP Scalable implementation - Bug 2347 - LrWpan Ascii traces are hooked to the wrong traces. - Bug 2353 - TCP Vegas implementation diff --git a/examples/tcp/tcp-variants-comparison.cc b/examples/tcp/tcp-variants-comparison.cc index 1e3bef8a8..051ea4ef0 100644 --- a/examples/tcp/tcp-variants-comparison.cc +++ b/examples/tcp/tcp-variants-comparison.cc @@ -178,8 +178,8 @@ int main (int argc, char *argv[]) CommandLine cmd; cmd.AddValue ("transport_prot", "Transport protocol to use: TcpNewReno, " - "TcpHybla, TcpHighSpeed, TcpVegas, TcpScalable, TcpWestwood, " - "TcpWestwoodPlus ", transport_prot); + "TcpHybla, TcpHighSpeed, TcpVegas, TcpScalable, TcpVeno, " + "TcpWestwood, TcpWestwoodPlus ", transport_prot); cmd.AddValue ("error_p", "Packet error rate", error_p); cmd.AddValue ("bandwidth", "Bottleneck bandwidth", bandwidth); cmd.AddValue ("delay", "Bottleneck delay", delay); @@ -246,6 +246,10 @@ int main (int argc, char *argv[]) { Config::SetDefault ("ns3::TcpL4Protocol::SocketType", TypeIdValue (TcpScalable::GetTypeId ())); } + else if (transport_prot.compare ("TcpVeno") == 0) + { + Config::SetDefault ("ns3::TcpL4Protocol::SocketType", TypeIdValue (TcpVeno::GetTypeId ())); + } else if (transport_prot.compare ("TcpWestwood") == 0) { // the default protocol type in ns3::TcpWestwood is WESTWOOD Config::SetDefault ("ns3::TcpL4Protocol::SocketType", TypeIdValue (TcpWestwood::GetTypeId ())); @@ -363,6 +367,7 @@ int main (int argc, char *argv[]) || transport_prot.compare ("TcpHybla") == 0 || transport_prot.compare ("TcpHighSpeed") == 0 || transport_prot.compare ("TcpVegas") == 0 + || transport_prot.compare ("TcpVeno") == 0 || transport_prot.compare ("TcpScalable") == 0) { Config::SetDefault ("ns3::TcpSocket::SegmentSize", UintegerValue (tcp_adu_size)); diff --git a/src/internet/doc/tcp.rst b/src/internet/doc/tcp.rst index 551645cf9..15a60dd7a 100644 --- a/src/internet/doc/tcp.rst +++ b/src/internet/doc/tcp.rst @@ -275,6 +275,37 @@ the following equation: More informations at: http://dl.acm.org/citation.cfm?id=956989 +Veno +^^^^ + +TCP Veno enhances Reno algorithm for more effectively dealing with random +packet loss in wireless access networks by employing Vegas's method in +estimating the backlog at the bottleneck queue to distinguish between +congestive and non-congestive states. + +The backlog (the number of packets accumulated at the bottleneck queue) is +calculated using Equation (1): + N = Actual * (RTT - BaseRTT) = Diff * BaseRTT (1) +where + Diff = Expected - Actual = cwnd/BaseRTT - cwnd/RTT + +Veno makes decision on cwnd modification based on the calculated N and its +predefined threshold beta. + +Specifically, it refines the additive increase algorithm of Reno so that the +connection can stay longer in the stable state by incrementing cwnd by +1/cwnd for every other new ACK received after the available bandwidth has +been fully utilized, i.e. when N exceeds beta. Otherwise, Veno increases +its cwnd by 1/cwnd upon every new ACK receipt as in Reno. + +In the multiplicative decrease algorithm, when Veno is in the non-congestive +state, i.e. when N is less than beta, Veno decrements its cwnd by only 1/5 +because the loss encountered is more likely a corruption-based loss than a +congestion-based. Only when N is greater than beta, Veno halves its sending +rate as in Reno. + +More informations at: http://dx.doi.org/10.1109/JSAC.2002.807336 + Validation ++++++++++ diff --git a/src/internet/model/tcp-veno.cc b/src/internet/model/tcp-veno.cc new file mode 100644 index 000000000..6511abc85 --- /dev/null +++ b/src/internet/model/tcp-veno.cc @@ -0,0 +1,253 @@ +/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ +/* + * Copyright (c) 2016 ResiliNets, ITTC, University of Kansas + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation; + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Author: Truc Anh N. Nguyen + * + * James P.G. Sterbenz , director + * ResiliNets Research Group http://wiki.ittc.ku.edu/resilinets + * Information and Telecommunication Technology Center (ITTC) + * and Department of Electrical Engineering and Computer Science + * The University of Kansas Lawrence, KS USA. + */ + +#include "tcp-veno.h" +#include "ns3/tcp-socket-base.h" +#include "ns3/log.h" + +namespace ns3 { + +NS_LOG_COMPONENT_DEFINE ("TcpVeno"); +NS_OBJECT_ENSURE_REGISTERED (TcpVeno); + +TypeId +TcpVeno::GetTypeId (void) +{ + static TypeId tid = TypeId ("ns3::TcpVeno") + .SetParent () + .AddConstructor () + .SetGroupName ("Internet") + .AddAttribute ("Beta", "Threshold for congestion detection", + UintegerValue (6), + MakeUintegerAccessor (&TcpVeno::m_beta), + MakeUintegerChecker ()) + ; + return tid; +} + +TcpVeno::TcpVeno (void) + : TcpNewReno (), + m_baseRtt (Time::Max ()), + m_minRtt (Time::Max ()), + m_cntRtt (0), + m_doingVenoNow (true), + m_diff (0), + m_inc (true), + m_ackCnt (0), + m_beta (6) +{ + NS_LOG_FUNCTION (this); +} + +TcpVeno::TcpVeno (const TcpVeno& sock) + : TcpNewReno (sock), + m_baseRtt (sock.m_baseRtt), + m_minRtt (sock.m_minRtt), + m_cntRtt (sock.m_cntRtt), + m_doingVenoNow (true), + m_diff (0), + m_inc (true), + m_ackCnt (sock.m_ackCnt), + m_beta (sock.m_beta) +{ + NS_LOG_FUNCTION (this); +} + +TcpVeno::~TcpVeno (void) +{ + NS_LOG_FUNCTION (this); +} + +Ptr +TcpVeno::Fork (void) +{ + return CopyObject (this); +} + +void +TcpVeno::PktsAcked (Ptr tcb, uint32_t segmentsAcked, + const Time& rtt) +{ + NS_LOG_FUNCTION (this << tcb << segmentsAcked << rtt); + + if (rtt.IsZero ()) + { + return; + } + + m_minRtt = std::min (m_minRtt, rtt); + NS_LOG_DEBUG ("Updated m_minRtt= " << m_minRtt); + + + m_baseRtt = std::min (m_baseRtt, rtt); + NS_LOG_DEBUG ("Updated m_baseRtt= " << m_baseRtt); + + // Update RTT counter + m_cntRtt++; + NS_LOG_DEBUG ("Updated m_cntRtt= " << m_cntRtt); +} + +void +TcpVeno::EnableVeno (Ptr tcb) +{ + NS_LOG_FUNCTION (this << tcb); + + m_doingVenoNow = true; + m_minRtt = Time::Max (); +} + +void +TcpVeno::DisableVeno () +{ + NS_LOG_FUNCTION (this); + + m_doingVenoNow = false; +} + +void +TcpVeno::CongestionStateSet (Ptr tcb, + const TcpSocketState::TcpCongState_t newState) +{ + NS_LOG_FUNCTION (this << tcb << newState); + if (newState == TcpSocketState::CA_OPEN) + { + EnableVeno (tcb); + NS_LOG_LOGIC ("Veno is now on."); + } + else + { + DisableVeno (); + NS_LOG_LOGIC ("Veno is turned off."); + } +} + +void +TcpVeno::IncreaseWindow (Ptr tcb, uint32_t segmentsAcked) +{ + NS_LOG_FUNCTION (this << tcb << segmentsAcked); + + if (!m_doingVenoNow) + { + // If Veno is not on, we follow NewReno algorithm + NS_LOG_LOGIC ("Veno is not turned on, we follow NewReno algorithm."); + TcpNewReno::IncreaseWindow (tcb, segmentsAcked); + return; + } + + // We do the Veno calculations only if we got enough RTT samples + if (m_cntRtt <= 2) + { // We do not have enough RTT samples, so we should behave like NewReno + NS_LOG_LOGIC ("We do not have enough RTT samples to perform Veno " + "calculations, we behave like NewReno."); + TcpNewReno::IncreaseWindow (tcb, segmentsAcked); + } + else + { + NS_LOG_LOGIC ("We have enough RTT samples to perform Veno calculations."); + + uint64_t targetCwnd; + uint32_t segCwnd = tcb->GetCwndInSegments (); + + // Calculate the cwnd we should have + targetCwnd = (uint64_t) segCwnd * (double) m_baseRtt.GetMilliSeconds () * 2; + targetCwnd = targetCwnd / (double) m_minRtt.GetMilliSeconds (); + NS_LOG_DEBUG ("Calculated targetCwnd = " << targetCwnd); + + // Calculate the difference between actual and target cwnd + m_diff = (segCwnd * 2) - targetCwnd; + NS_LOG_DEBUG ("Calculated m_diff = " << m_diff); + + if (tcb->m_cWnd < tcb->m_ssThresh) + { // Slow start mode. Veno employs same slow start algorithm as NewReno's. + NS_LOG_LOGIC ("We are in slow start, behave like NewReno."); + segmentsAcked = TcpNewReno::SlowStart (tcb, segmentsAcked); + } + else + { // Congestion avoidance mode + NS_LOG_LOGIC ("We are in congestion avoidance, execute Veno additive " + "increase algo."); + if (m_diff < m_beta) + { + // Available bandwidth is not fully utilized, + // increase cwnd by 1 every RTT + NS_LOG_LOGIC ("Available bandwidth not fully utilized, increase " + "cwnd by 1 every RTT"); + TcpNewReno::CongestionAvoidance (tcb, segmentsAcked); + } + else + { + // Available bandwidth is fully utilized, + // increase cwnd by 1 every other RTT + NS_LOG_LOGIC ("Available bandwidth fully utilized, increase cwnd " + "by 1 every other RTT"); + if (m_inc) + { + TcpNewReno::CongestionAvoidance (tcb, segmentsAcked); + m_inc = false; + } + else + { + m_inc = true; + } + } + } + } + + // Reset minRtt + m_minRtt = Time::Max (); +} + +std::string +TcpVeno::GetName () const +{ + return "TcpVeno"; +} + +uint32_t +TcpVeno::GetSsThresh (Ptr tcb, + uint32_t bytesInFlight) +{ + NS_LOG_FUNCTION (this << tcb << bytesInFlight); + + if (m_diff < m_beta) + { + // random loss due to bit errors is most likely to have occurred, + // we cut cwnd by 1/5 + NS_LOG_LOGIC ("Random loss is most likely to have occurred, " + "cwnd is reduced by 1/5"); + return std::max (bytesInFlight * 4 / 5, 2 * tcb->m_segmentSize); + } + else + { + // congestion-based loss is most likely to have occurred, + // we reduce cwnd by 1/2 as in NewReno + NS_LOG_LOGIC ("Congestive loss is most likely to have occurred, " + "cwnd is halved"); + return std::max (bytesInFlight / 2, 2 * tcb->m_segmentSize); + } +} + +} // namespace ns3 diff --git a/src/internet/model/tcp-veno.h b/src/internet/model/tcp-veno.h new file mode 100644 index 000000000..604b2550b --- /dev/null +++ b/src/internet/model/tcp-veno.h @@ -0,0 +1,175 @@ +/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ +/* + * Copyright (c) 2016 ResiliNets, ITTC, University of Kansas + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation; + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Author: Truc Anh N. Nguyen + * + * James P.G. Sterbenz , director + * ResiliNets Research Group http://wiki.ittc.ku.edu/resilinets + * Information and Telecommunication Technology Center (ITTC) + * and Department of Electrical Engineering and Computer Science + * The University of Kansas Lawrence, KS USA. + */ + +#ifndef TCPVENO_H +#define TCPVENO_H + +#include "ns3/tcp-congestion-ops.h" + +namespace ns3 { + +/** + * \ingroup tcp + * + * \brief An implementation of TCP Veno + * + * TCP Veno enhances Reno algorithm for more effectively dealing with random + * packet loss in wireless access networks by employing Vegas's method in + * estimating the backlog at the bottleneck queue to distinguish between + * congestive and non-congestive states. + * + * The backlog (the number of packets accumulated at the bottleneck queue) is + * calculated using Equation (1): + * + * N = Actual * (RTT - BaseRTT) = Diff * BaseRTT (1) + * where + * Diff = Expected - Actual = cwnd/BaseRTT - cwnd/RTT + * + * Veno makes decision on cwnd modification based on the calculated N and its + * predefined threshold beta. + * + * Specifically, it refines the additive increase algorithm of Reno so that the + * connection can stay longer in the stable state by incrementing cwnd by + * 1/cwnd for every other new ACK received after the available bandwidth has + * been fully utilized, i.e. when N exceeds beta. Otherwise, Veno increases + * its cwnd by 1/cwnd upon every new ACK receipt as in Reno. + * + * In the multiplicative decrease algorithm, when Veno is in the non-congestive + * state, i.e. when N is less than beta, Veno decrements its cwnd by only 1/5 + * because the loss encountered is more likely a corruption-based loss than a + * congestion-based. Only when N is greater than beta, Veno halves its sending + * rate as in Reno. + * + * More information: http://dx.doi.org/10.1109/JSAC.2002.807336 + */ + +class TcpVeno : public TcpNewReno +{ +public: + /** + * \brief Get the type ID. + * \return the object TypeId + */ + static TypeId GetTypeId (void); + + /** + * Create an unbound tcp socket. + */ + TcpVeno (void); + + /** + * \brief Copy constructor + * \param sock the object to copy + */ + TcpVeno (const TcpVeno& sock); + virtual ~TcpVeno (void); + + virtual std::string GetName () const; + + /** + * \brief Perform RTT sampling needed to execute Veno algorithm + * + * The function filters RTT samples from the last RTT to find + * the current smallest propagation delay + queueing delay (m_minRtt). + * We take the minimum to avoid the effects of delayed ACKs. + * + * The function also min-filters all RTT measurements seen to find the + * propagation delay (m_baseRtt). + * + * \param tcb internal congestion state + * \param segementsAcked count of segments ACKed + * \param rtt last RTT + * + */ + virtual void PktsAcked (Ptr tcb, uint32_t segmentsAcked, + const Time& rtt); + + /** + * \brief Enable/disable Veno depending on the congestion state + * + * We only start a Veno when we are in normal congestion state (CA_OPEN state). + * + * \param tcb internal congestion state + * \param newState new congestion state to which the TCP is going to switch + */ + virtual void CongestionStateSet (Ptr tcb, + const TcpSocketState::TcpCongState_t newState); + + /** + * \brief Adjust cwnd following Veno additive increase algorithm + * + * \param tcb internal congestion state + * \param segmentsAcked count of segments ACKed + */ + virtual void IncreaseWindow (Ptr tcb, uint32_t segmentsAcked); + + /** + * \brief Get slow start threshold during Veno multiplicative-decrease phase + * + * \param tcb internal congestion state + * \param bytesInFlight bytes in flight + * + * \return the slow start threshold value + */ + virtual uint32_t GetSsThresh (Ptr tcb, + uint32_t bytesInFlight); + + virtual Ptr Fork (); + +protected: +private: + /** + * \brief Enable Veno algorithm to start Veno sampling + * + * Veno algorithm is enabled in the following situations: + * 1. at the establishment of a connection + * 2. after an RTO + * 3. after fast recovery + * 4. when an idle connection is restarted + * + * \param tcb internal congestion state + */ + void EnableVeno (Ptr tcb); + + /** + * \brief Turn off Veno + */ + void DisableVeno (); + +private: + Time m_baseRtt; //!< Minimum of all RTT measurements seen during connection + Time m_minRtt; //!< Minimum of RTTs measured within last RTT + uint32_t m_cntRtt; //!< # of RTT measurements during last RTT + bool m_doingVenoNow; //!< If true, do Veno for this RTT + uint32_t m_diff; //!< Difference between expected and actual throughput + bool m_inc; //!< If true, cwnd needs to be incremented + uint32_t m_ackCnt; //!< Number of received ACK + uint32_t m_beta; //!< Threshold for congestion detection +}; + +} // namespace ns3 + +#endif // TCPVENO_H diff --git a/src/internet/test/tcp-veno-test.cc b/src/internet/test/tcp-veno-test.cc new file mode 100644 index 000000000..4c2e5ae33 --- /dev/null +++ b/src/internet/test/tcp-veno-test.cc @@ -0,0 +1,220 @@ +/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ +/* + * Copyright (c) 2016 ResiliNets, ITTC, University of Kansas + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation; + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Author: Truc Anh N. Nguyen + * + * James P.G. Sterbenz , director + * ResiliNets Research Group http://wiki.ittc.ku.edu/resilinets + * Information and Telecommunication Technology Center (ITTC) + * and Department of Electrical Engineering and Computer Science + * The University of Kansas Lawrence, KS USA. + */ + +#include "ns3/test.h" +#include "ns3/log.h" +#include "ns3/tcp-congestion-ops.h" +#include "ns3/tcp-socket-base.h" +#include "ns3/tcp-veno.h" + +namespace ns3 { + +NS_LOG_COMPONENT_DEFINE ("TcpVenoTestSuite"); + +/** + * \brief Testing the additive increase and multiplicative decrease of TcpVeno + */ +class TcpVenoTest : public TestCase +{ +public: + TcpVenoTest (uint32_t cWnd, + uint32_t segmentSize, + uint32_t ssThresh, + Time rtt, + uint32_t segmentsAcked, + uint32_t numRtt, + const std::string &name); + +private: + virtual void DoRun (void); + uint32_t AdditiveIncrease (Ptr cong, uint32_t diff, UintegerValue beta); + uint32_t MultiplicativeDecrease (uint32_t diff, UintegerValue beta); + + uint32_t m_cWnd; + uint32_t m_segmentSize; + uint32_t m_ssThresh; + Time m_rtt; + uint32_t m_segmentsAcked; + uint32_t m_numRtt; + bool m_inc; + Ptr m_state; +}; + +TcpVenoTest::TcpVenoTest (uint32_t cWnd, + uint32_t segmentSize, + uint32_t ssThresh, + Time rtt, + uint32_t segmentsAcked, + uint32_t numRtt, + const std::string &name) + : TestCase (name), + m_cWnd (cWnd), + m_segmentSize (segmentSize), + m_ssThresh (ssThresh), + m_rtt (rtt), + m_segmentsAcked (segmentsAcked), + m_numRtt (numRtt), + m_inc (true) +{ +} + +void +TcpVenoTest::DoRun () +{ + m_state = CreateObject (); + + m_state->m_cWnd = m_cWnd; + m_state->m_segmentSize = m_segmentSize; + m_state->m_ssThresh = m_ssThresh; + + Ptr cong = CreateObject (); + + // Set baseRtt to 100 ms + cong->PktsAcked (m_state, m_segmentsAcked, MilliSeconds (100)); + + // Re-set Veno to assign a new value of minRtt + cong->CongestionStateSet (m_state, TcpSocketState::CA_OPEN); + cong->PktsAcked (m_state, m_segmentsAcked, m_rtt); + + // Another call to PktsAcked to increment cntRtt beyond 2 + cong->PktsAcked (m_state, m_segmentsAcked, m_rtt); + + Time baseRtt = MilliSeconds (100); + uint32_t segCwnd = m_cWnd / m_segmentSize; + + // Calculate expected throughput + uint64_t expectedCwnd; + expectedCwnd = (uint64_t) segCwnd * (double) baseRtt.GetMilliSeconds () * 2 / (double) m_rtt.GetMilliSeconds (); + + // Calculate the difference between actual and expected throughput + uint32_t diff; + diff = (segCwnd * 2) - expectedCwnd; + + // Get the beta attribute + UintegerValue beta; + cong->GetAttribute ("Beta", beta); + + while (m_numRtt != 0) + { + // Update cwnd using Veno's additive increase algorithm + cong->IncreaseWindow (m_state, m_segmentsAcked); + + // Our calculation of cwnd + uint32_t calculatedCwnd = AdditiveIncrease (cong, diff, beta); + + NS_TEST_ASSERT_MSG_EQ (m_state->m_cWnd.Get (), calculatedCwnd, + "CWnd has not updated correctly based on Veno linear increase algorithm"); + m_numRtt--; + } + + // Update ssthresh using Veno's multiplicative decrease algorithm + uint32_t ssThresh = cong->GetSsThresh (m_state, m_state->m_cWnd); + + // Our calculation of ssthresh + uint32_t calculatedSsThresh = MultiplicativeDecrease (diff, beta); + + NS_TEST_ASSERT_MSG_EQ (ssThresh, calculatedSsThresh, + "Veno has not decremented cWnd correctly based on its multiplicative decrease algo."); +} + +uint32_t +TcpVenoTest::AdditiveIncrease (Ptr cong, uint32_t diff, UintegerValue beta) +{ + if (m_cWnd < m_ssThresh) + { // Slow start + if (m_segmentsAcked >= 1) + { + m_cWnd += m_segmentSize; + m_segmentsAcked--; + } + } + else + { // Congestion avoidance + if (diff < beta.Get ()) + { // Increase cwnd by 1 every RTT when bandwidth is not fully utilized + if (m_segmentsAcked > 0) + { + double adder = static_cast (m_segmentSize * m_segmentSize) / m_cWnd; + adder = std::max (1.0, adder); + m_cWnd += static_cast (adder); + } + } + else + { // Increase cwnd by 1 every other RTT when bandwidth is fully utilized + if (m_inc) + { + if (m_segmentsAcked > 0) + { + double adder = static_cast (m_segmentSize * m_segmentSize) / m_cWnd; + adder = std::max (1.0, adder); + m_cWnd += static_cast (adder); + } + m_inc = false; + } + else + { + m_inc = true; + } + } + } + return m_cWnd; +} + +uint32_t +TcpVenoTest::MultiplicativeDecrease (uint32_t diff, UintegerValue beta) +{ + uint32_t calculatedSsThresh; + if (diff < beta.Get ()) + { + calculatedSsThresh = std::max (2 * m_segmentSize, m_cWnd * 4 / 5); + } + else + { + calculatedSsThresh = std::max (2 * m_segmentSize, m_cWnd / 2); + } + return calculatedSsThresh; +} + + +// ------------------------------------------------------------------- +static class TcpVenoTestSuite : public TestSuite +{ +public: + TcpVenoTestSuite () : TestSuite ("tcp-veno-test", UNIT) + { + AddTestCase (new TcpVenoTest (38 * 1446, 1446, 40 * 1446, MilliSeconds (100), 1, 1, + "Veno test on cWnd in slow start and non-congestive loss"), + TestCase::QUICK); + AddTestCase (new TcpVenoTest (30 * 536, 536, 20 * 536, MilliSeconds (106), 1, 1, + "Veno test on cWnd with diff < beta"), + TestCase::QUICK); + AddTestCase (new TcpVenoTest (60 * 536, 536, 40 * 536, MilliSeconds (106), 1, 3, + "Veno increment test on cWnd with diff > beta"), + TestCase::QUICK); + } +} g_tcpVenoTest; + +} // namespace ns3 diff --git a/src/internet/wscript b/src/internet/wscript index 45db3cad6..15cda4de1 100644 --- a/src/internet/wscript +++ b/src/internet/wscript @@ -151,6 +151,7 @@ def build(bld): 'model/tcp-congestion-ops.cc', 'model/tcp-westwood.cc', 'model/tcp-scalable.cc', + 'model/tcp-veno.cc', 'model/tcp-rx-buffer.cc', 'model/tcp-tx-buffer.cc', 'model/tcp-option.cc', @@ -252,6 +253,7 @@ def build(bld): 'test/tcp-hybla-test.cc', 'test/tcp-vegas-test.cc', 'test/tcp-scalable-test.cc', + 'test/tcp-veno-test.cc', 'test/tcp-zero-window-test.cc', 'test/tcp-pkts-acked-test.cc', 'test/tcp-rtt-estimation.cc', @@ -358,6 +360,7 @@ def build(bld): 'model/tcp-congestion-ops.h', 'model/tcp-westwood.h', 'model/tcp-scalable.h', + 'model/tcp-veno.h', 'model/tcp-socket-base.h', 'model/tcp-tx-buffer.h', 'model/tcp-rx-buffer.h',