--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/internet/model/tcp-westwood.h Thu Apr 18 15:57:07 2013 -0400
@@ -0,0 +1,222 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013 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
+ *
+ * Authors: Siddharth Gangadhar <siddharth@ittc.ku.edu>, Truc Anh N. Nguyen <annguyen@ittc.ku.edu>,
+ * and Greeshma Umapathi
+ *
+ * James P.G. Sterbenz <jpgs@ittc.ku.edu>, 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.
+ *
+ * Work supported in part by NSF FIND (Future Internet Design) Program
+ * under grant CNS-0626918 (Postmodern Internet Architecture),
+ * NSF grant CNS-1050226 (Multilayer Network Resilience Analysis and Experimentation on GENI),
+ * US Department of Defense (DoD), and ITTC at The University of Kansas.
+ */
+
+#ifndef TCP_WESTWOOD_H
+#define TCP_WESTWOOD_H
+
+#include "tcp-socket-base.h"
+#include "ns3/packet.h"
+
+namespace ns3 {
+
+/**
+ * \ingroup socket
+ * \ingroup tcp
+ *
+ * \brief An implementation of a stream socket using TCP.
+ *
+ * This class contains the implementation of TCP Westwood and Westwood+.
+ *
+ * Westwood and Westwood+ employ the AIAD (Additive Increase/Adaptive Decrease)
+ * congestion control paradigm. When a congestion episode happens,
+ * instead of halving the cwnd, these protocols try to estimate the network's
+ * bandwidth and use the estimated value to adjust the cwnd.
+ * While Westwood performs the bandwidth sampling every ACK reception,
+ * Westwood+ samples the bandwidth every RTT.
+ *
+ * The two main methods in the implementation are the CountAck (const TCPHeader&)
+ * and the EstimateBW (int, const, Time). The CountAck method calculates
+ * the number of acknowledged segments on the receipt of an ACK.
+ * The EstimateBW estimates the bandwidth based on the value returned by CountAck
+ * and the sampling interval (last ACK inter-arrival time for Westwood and last RTT for Westwood+).
+ */
+class TcpWestwood : public TcpSocketBase
+{
+public:
+ static TypeId GetTypeId (void);
+
+ TcpWestwood (void);
+ TcpWestwood (const TcpWestwood& sock);
+ virtual ~TcpWestwood (void);
+
+ enum ProtocolType
+ {
+ WESTWOOD,
+ WESTWOODPLUS
+ };
+
+ enum FilterType
+ {
+ NONE,
+ TUSTIN
+ };
+
+ // From TcpSocketBase
+ virtual int Connect (const Address &address);
+ virtual int Listen (void);
+
+protected:
+ /**
+ * Limit the size of outstanding data based on the cwnd and the receiver's advertised window
+ *
+ * \return the max. possible number of unacked bytes
+ */
+ virtual uint32_t Window (void);
+
+ /**
+ * Call CopyObject<TcpWestwood> to clone me
+ */
+ virtual Ptr<TcpSocketBase> Fork (void);
+
+ /**
+ * Process the newly received ACK
+ *
+ * \param packet the received ACK packet
+ * \param tcpHeader the header attached to the ACK packet
+ */
+ virtual void ReceivedAck (Ptr<Packet> packet, const TcpHeader& tcpHeader);
+
+ /**
+ * Adjust the cwnd based on the current congestion control phase,
+ * and then call the TcpSocketBase::NewAck() to complete the processing
+ *
+ * \param seq the acknowledgment number
+ */
+ virtual void NewAck (SequenceNumber32 const& seq);
+
+ /**
+ * Adjust the cwnd using the currently estimated bandwidth,
+ * retransmit the missing packet, and enter fast recovery if 3 DUPACKs are received
+ *
+ * \param header the TCP header of the ACK packet
+ * \param count the number of DUPACKs
+ */
+ virtual void DupAck (const TcpHeader& header, uint32_t count);
+
+ /**
+ * Upon an RTO event, adjust the cwnd using the currently estimated bandwidth,
+ * retransmit the missing packet, and exit fast recovery
+ */
+ virtual void Retransmit (void);
+
+ /**
+ * Estimate the RTT, record the minimum value,
+ * and run a clock on the RTT to trigger Westwood+ bandwidth sampling
+ */
+ virtual void EstimateRtt (const TcpHeader& header);
+
+ // Implementing ns3::TcpSocket -- Attribute get/set
+ /**
+ * \param size the segment size to be used in a connection
+ */
+ virtual void SetSegSize (uint32_t size);
+
+ /**
+ * \param the slow-start threshold
+ */
+ virtual void SetSSThresh (uint32_t threshold);
+
+ /**
+ * \return the slow-start threshold
+ */
+ virtual uint32_t GetSSThresh (void) const;
+
+ /**
+ * \param cwnd the initial cwnd
+ */
+ virtual void SetInitialCwnd (uint32_t cwnd);
+
+ /**
+ * \return the initial cwnd
+ */
+ virtual uint32_t GetInitialCwnd (void) const;
+
+private:
+ /**
+ * Initialize cwnd at the beginning of a connection
+ */
+ void InitializeCwnd (void);
+
+ /**
+ * Calculate the number of acknowledged packets upon the receipt of an ACK packet
+ *
+ * \param tcpHeader the header of the received ACK packet
+ * \return the number of ACKed packets
+ */
+ int CountAck (const TcpHeader& tcpHeader);
+
+ /**
+ * Update the total number of acknowledged packets during the current RTT
+ *
+ * \param acked the number of packets the currently received ACK acknowledges
+ */
+ void UpdateAckedSegments (int acked);
+
+ /**
+ * Estimate the network's bandwidth
+ *
+ * \param acked the number of acknowledged packets returned by CountAck
+ * \param tcpHeader the header of the packet
+ * \param rtt the RTT estimation
+ */
+ void EstimateBW (int acked, const TcpHeader& tcpHeader, Time rtt);
+
+ /**
+ * Tustin filter
+ */
+ void Filtering (void);
+
+protected:
+ TracedValue<uint32_t> m_cWnd; //< Congestion window
+ uint32_t m_ssThresh; //< Slow Start Threshold
+ uint32_t m_initialCWnd; //< Initial cWnd value
+ bool m_inFastRec; //< Currently in fast recovery if TRUE
+
+ TracedValue<double> m_currentBW; //< Current value of the estimated BW
+ double m_lastSampleBW; //< Last bandwidth sample
+ double m_lastBW; //< Last bandwidth sample after being filtered
+ Time m_minRtt; //< Minimum RTT
+ double m_lastAck; //< The time last ACK was received
+ SequenceNumber32 m_prevAckNo; //< Previously received ACK number
+ int m_accountedFor; //< The number of received DUPACKs
+ enum ProtocolType m_pType; //< 0 for Westwood, 1 for Westwood+
+ enum FilterType m_fType; //< 0 for none, 1 for Tustin
+
+ int m_ackedSegments; //< The number of segments ACKed between RTTs
+ bool m_IsCount; //< Start keeping track of m_ackedSegments for Westwood+ if TRUE
+ EventId m_bwEstimateEvent; //< The BW estimation event for Westwood+
+
+};
+
+} // namespace ns3
+
+#endif /* TCP_WESTWOOD_H */