1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

     2 //

     3 // Copyright (c) 2006 Georgia Tech Research Corporation

     4 //

     5 // This program is free software; you can redistribute it and/or modify

     6 // it under the terms of the GNU General Public License version 2 as

     7 // published by the Free Software Foundation;

     8 //

     9 // This program is distributed in the hope that it will be useful,

    10 // but WITHOUT ANY WARRANTY; without even the implied warranty of

    11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12 // GNU General Public License for more details.

    13 //

    14 // You should have received a copy of the GNU General Public License

    15 // along with this program; if not, write to the Free Software

    16 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    17 //

    18 // Author: Rajib Bhattacharjea<raj.b@gatech.edu>

    19 //

    20 

    21 // Georgia Tech Network Simulator - Round Trip Time Estimation Class

    22 // George F. Riley.  Georgia Tech, Spring 2002

    23 

    24 // Implements several variations of round trip time estimators

    25 

    26 #ifndef __rtt_estimator_h__

    27 #define __rtt_estimator_h__

    28 

    29 #include <deque>

    30 #include "sequence-number.h"

    31 #include "ns3/nstime.h"

    32 #include "ns3/object.h"

    33 

    34 namespace ns3 {

    35 

    36 class RttHistory {

    37 public:

    38   RttHistory (SequenceNumber s, uint32_t c, Time t);

    39   RttHistory (const RttHistory& h); // Copy constructor

    40 public:

    41   SequenceNumber  seq;    // First sequence number in packet sent

    42   uint32_t        count;  // Number of bytes sent

    43   Time            time;   // Time this one was sent

    44   bool            retx;   // True if this has been retransmitted

    45 };

    46 

    47 typedef std::deque<RttHistory> RttHistory_t;

    48 

    49 class RttEstimator : public Object {  //  Base class for all RTT Estimators

    50 public:

    51   static TypeId GetTypeId (void);

    52 

    53   RttEstimator();

    54   RttEstimator(const RttEstimator&); // Copy constructor

    55   virtual ~RttEstimator();

    56 

    57   virtual void SentSeq(SequenceNumber, uint32_t);

    58   virtual Time AckSeq(SequenceNumber);

    59   virtual void ClearSent();

    60   virtual void   Measurement(Time t) = 0;

    61   virtual Time Estimate() = 0;

    62   virtual Time RetransmitTimeout() = 0;

    63   void Init(SequenceNumber s) { next = s;}

    64   virtual Ptr<RttEstimator> Copy() const = 0;

    65   virtual void IncreaseMultiplier();

    66   virtual void ResetMultiplier();

    67   virtual void Reset();

    68 

    69 private:

    70   SequenceNumber        next;    // Next expected sequence to be sent

    71   RttHistory_t history; // List of sent packet

    72   double m_maxMultiplier;

    73 public:

    74   Time       est;     // Current estimate

    75   uint32_t      nSamples;// Number of samples

    76   double       multiplier;   // RTO Multiplier

    77 };

    78 

    79 // The "Mean-Deviation" estimator, as discussed by Van Jacobson

    80 // "Congestion Avoidance and Control", SIGCOMM 88, Appendix A

    81 

    82   //Doc:Class Class {\tt RttMeanDeviation} implements the "Mean--Deviation" estimator

    83   //Doc:Class as described by Van Jacobson 

    84   //Doc:Class "Congestion Avoidance and Control", SIGCOMM 88, Appendix A

    85 class RttMeanDeviation : public RttEstimator {

    86 public :

    87   static TypeId GetTypeId (void);

    88 

    89   RttMeanDeviation ();

    90 

    91 

    92   //Doc:Method

    93   RttMeanDeviation (const RttMeanDeviation&); // Copy constructor

    94     //Doc:Desc Copy constructor.

    95     //Doc:Arg1 {\tt RttMeanDeviation} object to copy.

    96 

    97   void Measurement (Time);

    98   Time Estimate () { return est;}

    99   Time Variance () { return variance;}

   100   Time RetransmitTimeout ();

   101   Ptr<RttEstimator> Copy () const;

   102   void Reset ();

   103   void Gain (double g) { gain = g;}

   104 

   105 public:

   106   double       gain;       // Filter gain

   107   Time       variance;   // Current variance

   108 };

   109 }//namespace ns3

   110 #endif

   111 

   112 

   113