1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3 * Copyright (c) 2015 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 * by: Amir Modarresi <amodarresi@ittc.ku.edu>
19 *
20 * James P.G. Sterbenz <jpgs@ittc.ku.edu>, director
21 * ResiliNets Research Group http://wiki.ittc.ku.edu/resilinets
22 * Information and Telecommunication Technology Center (ITTC)
23 * and Department of Electrical Engineering and Computer Science
24 * The University of Kansas Lawrence, KS USA.
25 */
26
27 #include "tcp-htcp.h"
28 #include "ns3/log.h"
29 #include "ns3/simulator.h"
30
31 namespace ns3 {
32
33 NS_LOG_COMPONENT_DEFINE ("TcpHtcp");
34
35 NS_OBJECT_ENSURE_REGISTERED (TcpHtcp);
36
GetTypeId(void)37 TypeId TcpHtcp::GetTypeId (void)
38 {
39 static TypeId tid = TypeId ("ns3::TcpHtcp")
40 .SetParent<TcpNewReno> ()
41 .AddConstructor<TcpHtcp> ()
42 .SetGroupName ("Internet")
43 .AddAttribute ("DefaultBackoff",
44 "The default AIMD backoff factor",
45 DoubleValue (0.5),
46 MakeDoubleAccessor (&TcpHtcp::m_defaultBackoff),
47 MakeDoubleChecker<double> (0,1))
48 .AddAttribute ("ThroughputRatio",
49 "Threshold value for updating beta",
50 DoubleValue (0.2),
51 MakeDoubleAccessor (&TcpHtcp::m_throughputRatio),
52 MakeDoubleChecker<double> ())
53 .AddAttribute ("DeltaL",
54 "Delta_L parameter in increase function",
55 TimeValue (Seconds (1)),
56 MakeTimeAccessor (&TcpHtcp::m_deltaL),
57 MakeTimeChecker ())
58 ;
59 return tid;
60 }
61
GetName() const62 std::string TcpHtcp::GetName () const
63 {
64 return "TcpHtcp";
65 }
66
TcpHtcp(void)67 TcpHtcp::TcpHtcp (void)
68 : TcpNewReno (),
69 m_alpha (0),
70 m_beta (0),
71 m_delta (0),
72 m_lastCon (0),
73 m_minRtt (Time::Max ()),
74 m_maxRtt (Time::Min ()),
75 m_throughput (0),
76 m_lastThroughput (0),
77 m_dataSent (0)
78 {
79 NS_LOG_FUNCTION (this);
80 }
81
TcpHtcp(const TcpHtcp & sock)82 TcpHtcp::TcpHtcp (const TcpHtcp& sock)
83 : TcpNewReno (sock),
84 m_alpha (sock.m_alpha),
85 m_beta (sock.m_beta),
86 m_defaultBackoff (sock.m_defaultBackoff),
87 m_throughputRatio (sock.m_throughputRatio),
88 m_delta (sock.m_delta),
89 m_deltaL (sock.m_deltaL),
90 m_lastCon (sock.m_lastCon),
91 m_minRtt (sock.m_minRtt),
92 m_maxRtt (sock.m_maxRtt),
93 m_throughput (sock.m_throughput),
94 m_lastThroughput (sock.m_lastThroughput),
95 m_dataSent (sock.m_dataSent)
96 {
97 NS_LOG_FUNCTION (this);
98 }
99
~TcpHtcp(void)100 TcpHtcp::~TcpHtcp (void)
101 {
102 NS_LOG_FUNCTION (this);
103 }
104
Fork(void)105 Ptr<TcpCongestionOps> TcpHtcp::Fork (void)
106 {
107 NS_LOG_FUNCTION (this);
108 return CopyObject<TcpHtcp> (this);
109 }
110
CongestionAvoidance(Ptr<TcpSocketState> tcb,uint32_t segmentsAcked)111 void TcpHtcp::CongestionAvoidance (Ptr<TcpSocketState> tcb,
112 uint32_t segmentsAcked)
113 {
114 NS_LOG_FUNCTION (this << tcb << segmentsAcked);
115 if (segmentsAcked > 0)
116 {
117 double adder = static_cast<double> (((tcb->m_segmentSize
118 * tcb->m_segmentSize) + (tcb->m_cWnd * m_alpha)) / tcb->m_cWnd);
119 adder = std::max (1.0, adder);
120 tcb->m_cWnd += static_cast<uint32_t> (adder);
121 NS_LOG_INFO ("In CongAvoid, updated to cwnd " << tcb->m_cWnd
122 << " ssthresh " << tcb->m_ssThresh);
123 }
124 }
125
UpdateAlpha(void)126 void TcpHtcp::UpdateAlpha (void)
127 {
128 NS_LOG_FUNCTION (this);
129
130 m_delta = (Simulator::Now () - m_lastCon);
131 if (m_delta <= m_deltaL)
132 {
133 m_alpha = 1;
134 }
135 else
136 {
137 Time diff = m_delta - m_deltaL;
138 double diffSec = diff.GetSeconds ();
139 // alpha=1+10(Delta-Delta_L)+[0.5(Delta-Delta_L)]^2 (seconds)
140 // from Leith and Shorten H-TCP paper
141 m_alpha = (1 + 10 * diffSec + 0.25 * (diffSec * diffSec));
142 }
143 m_alpha = 2 * (1 - m_beta) * m_alpha;
144 if (m_alpha < 1)
145 {
146 m_alpha = 1;
147 }
148 NS_LOG_DEBUG ("Updated m_alpha: " << m_alpha);
149 }
150
UpdateBeta(void)151 void TcpHtcp::UpdateBeta (void)
152 {
153 NS_LOG_FUNCTION (this);
154
155 // Default value for m_beta
156 m_beta = m_defaultBackoff;
157
158 if (m_throughput > m_lastThroughput && m_lastThroughput > 0)
159 {
160 uint32_t diff = m_throughput - m_lastThroughput;
161 if (diff / m_lastThroughput <= m_throughputRatio)
162 {
163 m_beta = m_minRtt.GetDouble () / m_maxRtt.GetDouble ();
164 }
165 }
166 NS_LOG_DEBUG ("Updated m_beta: " << m_beta);
167 }
168
GetSsThresh(Ptr<const TcpSocketState> tcb,uint32_t bytesInFlight)169 uint32_t TcpHtcp::GetSsThresh (Ptr<const TcpSocketState> tcb,
170 uint32_t bytesInFlight)
171 {
172 NS_LOG_FUNCTION (this << tcb << bytesInFlight);
173
174 m_lastCon = Simulator::Now ();
175
176 UpdateBeta ();
177 UpdateAlpha ();
178
179 uint32_t segWin = 2 * tcb->m_segmentSize;
180 uint32_t bFlight = static_cast<uint32_t> (bytesInFlight * m_beta);
181 uint32_t ssThresh = std::max (segWin, bFlight);
182 m_minRtt = Time::Max ();
183 m_maxRtt = Time::Min ();
184 m_lastThroughput = m_throughput;
185 m_throughput = 0;
186 m_dataSent = 0;
187 NS_LOG_DEBUG (this << " ssThresh: " << ssThresh << " m_beta: " << m_beta);
188 return ssThresh;
189 }
190
PktsAcked(Ptr<TcpSocketState> tcb,uint32_t segmentsAcked,const Time & rtt)191 void TcpHtcp::PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
192 const Time &rtt)
193 {
194
195 NS_LOG_FUNCTION (this << tcb << segmentsAcked << rtt);
196 NS_LOG_DEBUG ("TcpSocketState: " << tcb->m_congState);
197 if (tcb->m_congState == TcpSocketState::CA_OPEN)
198 {
199 m_dataSent += segmentsAcked * tcb->m_segmentSize;
200 }
201
202 m_throughput = static_cast<uint32_t> (m_dataSent
203 / (Simulator::Now ().GetSeconds () - m_lastCon.GetSeconds ()));
204
205 UpdateAlpha ();
206 if (rtt < m_minRtt)
207 {
208 m_minRtt = rtt;
209 NS_LOG_DEBUG ("Updated m_minRtt=" << m_minRtt);
210 }
211 if (rtt > m_maxRtt)
212 {
213 m_maxRtt = rtt;
214 NS_LOG_DEBUG ("Updated m_maxRtt=" << m_maxRtt);
215 }
216 }
217
218 } // namespace ns3
219