A Discrete-Event Network Simulator
API
backoff.cc
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1/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2/*
3 * Copyright (c) 2007, Emmanuelle Laprise
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: Emmanuelle Laprise <emmanuelle.laprise@bluekazoo.ca>
19 */
20
21#include "backoff.h"
22#include "ns3/log.h"
23
24namespace ns3 {
25
26NS_LOG_COMPONENT_DEFINE ("Backoff");
27
29{
31 m_minSlots = 1;
32 m_maxSlots = 1000;
33 m_ceiling = 10;
34 m_maxRetries = 1000;
36 m_rng = CreateObject<UniformRandomVariable> ();
37
39}
40
41Backoff::Backoff(Time slotTime, uint32_t minSlots, uint32_t maxSlots, uint32_t ceiling, uint32_t maxRetries)
42{
43 m_slotTime = slotTime;
44 m_minSlots = minSlots;
45 m_maxSlots = maxSlots;
46 m_ceiling = ceiling;
47 m_maxRetries = maxRetries;
49 m_rng = CreateObject<UniformRandomVariable> ();
50}
51
52Time
54{
55 uint32_t ceiling;
56
58 {
59 ceiling = m_ceiling;
60 }
61 else
62 {
63 ceiling = m_numBackoffRetries;
64 }
65
66 uint32_t minSlot = m_minSlots;
67 uint32_t maxSlot = (uint32_t)pow (2, ceiling) - 1;
68 if (maxSlot > m_maxSlots)
69 {
70 maxSlot = m_maxSlots;
71 }
72
73 uint32_t backoffSlots = (uint32_t)m_rng->GetValue (minSlot, maxSlot);
74
75 Time backoff = Time (backoffSlots * m_slotTime);
76 return backoff;
77}
78
79void
81{
83}
84
85bool
87{
89}
90
91void
93{
95}
96
97int64_t
98Backoff::AssignStreams (int64_t stream)
99{
100 NS_LOG_FUNCTION (this << stream);
101 m_rng->SetStream (stream);
102 return 1;
103}
104
105} // namespace ns3
void ResetBackoffTime(void)
Indicates to the backoff object that the last packet was successfully transmitted and that the number...
Definition: backoff.cc:80
uint32_t m_maxRetries
Maximum number of transmission retries before the packet is dropped.
Definition: backoff.h:57
bool MaxRetriesReached(void)
Definition: backoff.cc:86
int64_t AssignStreams(int64_t stream)
Assign a fixed random variable stream number to the random variables used by this model.
Definition: backoff.cc:98
uint32_t m_maxSlots
Maximum number of backoff slots (when multiplied by m_slotTime, determines maximum backoff time)
Definition: backoff.h:47
uint32_t m_numBackoffRetries
Number of times that the transmitter has tried to unsuccessfully transmit the current packet.
Definition: backoff.h:113
uint32_t m_minSlots
Minimum number of backoff slots (when multiplied by m_slotTime, determines minimum backoff time)
Definition: backoff.h:42
Time GetBackoffTime()
Definition: backoff.cc:53
Ptr< UniformRandomVariable > m_rng
Random number generator.
Definition: backoff.h:118
uint32_t m_ceiling
Caps the exponential function when the number of retries reaches m_ceiling.
Definition: backoff.h:52
Time m_slotTime
Length of one slot.
Definition: backoff.h:62
void IncrNumRetries(void)
Increments the number of retries by 1.
Definition: backoff.cc:92
Backoff(void)
Definition: backoff.cc:28
void SetStream(int64_t stream)
Specifies the stream number for the RngStream.
Simulation virtual time values and global simulation resolution.
Definition: nstime.h:104
double GetValue(double min, double max)
Get the next random value, as a double in the specified range .
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:206
#define NS_LOG_FUNCTION(parameters)
If log level LOG_FUNCTION is enabled, this macro will output all input parameters separated by ",...
Time MicroSeconds(uint64_t value)
Construct a Time in the indicated unit.
Definition: nstime.h:1261
void(* Time)(Time oldValue, Time newValue)
TracedValue callback signature for Time.
Definition: nstime.h:794
Every class exported by the ns3 library is enclosed in the ns3 namespace.