A Discrete-Event Network Simulator
API
tcp-westwood.cc
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1/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2/*
3 * Copyright (c) 2013 ResiliNets, ITTC, University of Kansas
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 * Authors: Siddharth Gangadhar <siddharth@ittc.ku.edu>,
19 * Truc Anh N. Nguyen <annguyen@ittc.ku.edu>,
20 * Greeshma Umapathi
21 *
22 * James P.G. Sterbenz <jpgs@ittc.ku.edu>, director
23 * ResiliNets Research Group http://wiki.ittc.ku.edu/resilinets
24 * Information and Telecommunication Technology Center (ITTC)
25 * and Department of Electrical Engineering and Computer Science
26 * The University of Kansas Lawrence, KS USA.
27 *
28 * Work supported in part by NSF FIND (Future Internet Design) Program
29 * under grant CNS-0626918 (Postmodern Internet Architecture),
30 * NSF grant CNS-1050226 (Multilayer Network Resilience Analysis and Experimentation on GENI),
31 * US Department of Defense (DoD), and ITTC at The University of Kansas.
32 */
33
34#include "tcp-westwood.h"
35#include "ns3/log.h"
36#include "ns3/simulator.h"
37#include "rtt-estimator.h"
38#include "tcp-socket-base.h"
39
40NS_LOG_COMPONENT_DEFINE ("TcpWestwood");
41
42namespace ns3 {
43
44NS_OBJECT_ENSURE_REGISTERED (TcpWestwood);
45
46TypeId
48{
49 static TypeId tid = TypeId("ns3::TcpWestwood")
51 .SetGroupName ("Internet")
52 .AddConstructor<TcpWestwood>()
53 .AddAttribute("FilterType", "Use this to choose no filter or Tustin's approximation filter",
56 .AddAttribute("ProtocolType", "Use this to let the code run as Westwood or WestwoodPlus",
60 .AddTraceSource("EstimatedBW", "The estimated bandwidth",
62 "ns3::TracedValueCallback::DataRate")
63 ;
64 return tid;
65}
66
68 TcpNewReno (),
69 m_currentBW (0),
70 m_lastSampleBW (0),
71 m_lastBW (0),
72 m_ackedSegments (0),
73 m_IsCount (false),
74 m_lastAck (0)
75{
76 NS_LOG_FUNCTION (this);
77}
78
80 TcpNewReno (sock),
81 m_currentBW (sock.m_currentBW),
82 m_lastSampleBW (sock.m_lastSampleBW),
83 m_lastBW (sock.m_lastBW),
84 m_pType (sock.m_pType),
85 m_fType (sock.m_fType),
86 m_IsCount (sock.m_IsCount)
87{
88 NS_LOG_FUNCTION (this);
89 NS_LOG_LOGIC ("Invoked the copy constructor");
90}
91
93{
94}
95
96void
98 const Time& rtt)
99{
100 NS_LOG_FUNCTION (this << tcb << packetsAcked << rtt);
101
102 if (rtt.IsZero ())
103 {
104 NS_LOG_WARN ("RTT measured is zero!");
105 return;
106 }
107
108 m_ackedSegments += packetsAcked;
109
111 {
112 EstimateBW (rtt, tcb);
113 }
115 {
116 if (!(rtt.IsZero () || m_IsCount))
117 {
118 m_IsCount = true;
121 this, rtt, tcb);
122 }
123 }
124}
125
126void
128{
129 NS_LOG_FUNCTION (this);
130
131 NS_ASSERT (!rtt.IsZero ());
132
134 {
135 Time currentAck = Simulator::Now ();
136
137 NS_ABORT_MSG_IF (currentAck == m_lastAck,
138 "This violates a model assumption and would lead to divide-by-zero; please report to ns-3 maintainers if this occurs.");
139
140 m_currentBW = DataRate (m_ackedSegments * tcb->m_segmentSize * 8.0 / (currentAck - m_lastAck).GetSeconds ());
141 m_lastAck = currentAck;
142 }
144 {
146 m_IsCount = false;
147 }
148
149 m_ackedSegments = 0;
150
151 NS_LOG_LOGIC ("Estimated BW: " << m_currentBW);
152
153 // Filter the BW sample
154
155 constexpr double alpha = 0.9;
156
158 {
159 DataRate sample_bwe = m_currentBW;
160 m_currentBW = (m_lastBW * alpha) + (((sample_bwe + m_lastSampleBW) * 0.5) * (1 - alpha));
161 m_lastSampleBW = sample_bwe;
163 }
164
165 NS_LOG_LOGIC ("Estimated BW after filtering: " << m_currentBW);
166}
167
170 [[maybe_unused]] uint32_t bytesInFlight)
171{
172 uint32_t ssThresh = static_cast<uint32_t> ((m_currentBW * tcb->m_minRtt) / 8.0);
173
174 NS_LOG_LOGIC ("CurrentBW: " << m_currentBW <<
175 " minRtt: " << tcb->m_minRtt <<
176 " ssThresh: " << ssThresh);
177
178 return std::max (2 * tcb->m_segmentSize, ssThresh);
179}
180
183{
184 return CreateObject<TcpWestwood> (*this);
185}
186
187} // namespace ns3
#define max(a, b)
Definition: 80211b.c:43
Class for representing data rates.
Definition: data-rate.h:89
Hold variables of type enum.
Definition: enum.h:55
void Cancel(void)
This method is syntactic sugar for the ns3::Simulator::Cancel method.
Definition: event-id.cc:53
static EventId Schedule(Time const &delay, FUNC f, Ts &&... args)
Schedule an event to expire after delay.
Definition: simulator.h:555
static Time Now(void)
Return the current simulation virtual time.
Definition: simulator.cc:195
The NewReno implementation.
uint32_t m_segmentSize
Segment size.
An implementation of TCP Westwood and Westwood+.
Definition: tcp-westwood.h:67
TracedValue< DataRate > m_currentBW
Current value of the estimated BW.
Definition: tcp-westwood.h:126
enum ProtocolType m_pType
0 for Westwood, 1 for Westwood+
Definition: tcp-westwood.h:129
enum FilterType m_fType
0 for none, 1 for Tustin
Definition: tcp-westwood.h:130
bool m_IsCount
Start keeping track of m_ackedSegments for Westwood+ if TRUE.
Definition: tcp-westwood.h:133
DataRate m_lastSampleBW
Last bandwidth sample.
Definition: tcp-westwood.h:127
void EstimateBW(const Time &rtt, Ptr< TcpSocketState > tcb)
Estimate the network's bandwidth.
virtual void PktsAcked(Ptr< TcpSocketState > tcb, uint32_t packetsAcked, const Time &rtt)
Timing information on received ACK.
Definition: tcp-westwood.cc:97
DataRate m_lastBW
Last bandwidth sample after being filtered.
Definition: tcp-westwood.h:128
virtual ~TcpWestwood(void)
Definition: tcp-westwood.cc:92
Time m_lastAck
The last ACK time.
Definition: tcp-westwood.h:135
uint32_t m_ackedSegments
The number of segments ACKed between RTTs.
Definition: tcp-westwood.h:132
virtual uint32_t GetSsThresh(Ptr< const TcpSocketState > tcb, uint32_t bytesInFlight)
Get the slow start threshold after a loss event.
virtual Ptr< TcpCongestionOps > Fork()
Copy the congestion control algorithm across sockets.
EventId m_bwEstimateEvent
The BW estimation event for Westwood+.
Definition: tcp-westwood.h:134
static TypeId GetTypeId(void)
Get the type ID.
Definition: tcp-westwood.cc:47
Simulation virtual time values and global simulation resolution.
Definition: nstime.h:103
double GetSeconds(void) const
Get an approximation of the time stored in this instance in the indicated unit.
Definition: nstime.h:379
bool IsZero(void) const
Exactly equivalent to t == 0.
Definition: nstime.h:300
a unique identifier for an interface.
Definition: type-id.h:59
TypeId SetParent(TypeId tid)
Set the parent TypeId.
Definition: type-id.cc:922
#define NS_ASSERT(condition)
At runtime, in debugging builds, if this condition is not true, the program prints the source file,...
Definition: assert.h:67
Ptr< const AttributeAccessor > MakeEnumAccessor(T1 a1)
Definition: enum.h:205
#define NS_ABORT_MSG_IF(cond, msg)
Abnormal program termination if a condition is true, with a message.
Definition: abort.h:108
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:205
#define NS_LOG_LOGIC(msg)
Use NS_LOG to output a message of level LOG_LOGIC.
Definition: log.h:289
#define NS_LOG_FUNCTION(parameters)
If log level LOG_FUNCTION is enabled, this macro will output all input parameters separated by ",...
#define NS_LOG_WARN(msg)
Use NS_LOG to output a message of level LOG_WARN.
Definition: log.h:265
void(* DataRate)(DataRate oldValue, DataRate newValue)
TracedValue callback signature for DataRate.
Definition: data-rate.h:329
#define NS_OBJECT_ENSURE_REGISTERED(type)
Register an Object subclass with the TypeId system.
Definition: object-base.h:45
Ptr< const TraceSourceAccessor > MakeTraceSourceAccessor(T a)
Create a TraceSourceAccessor which will control access to the underlying trace source.
Every class exported by the ns3 library is enclosed in the ns3 namespace.
Ptr< const AttributeChecker > MakeEnumChecker(int v, std::string n, Ts... args)
Make an EnumChecker pre-configured with a set of allowed values by name.
Definition: enum.h:162
float alpha
Plot alpha value (transparency)