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/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
/*
* Copyright (c) 2011 University of California, Los Angeles
*
* 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
*
* Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
*/
#include "ndn-limits.h"
#include "ns3/log.h"
#include "ns3/simulator.h"
#include "ns3/random-variable.h"
NS_LOG_COMPONENT_DEFINE ("ndn.Limits");
namespace ns3 {
namespace ndn {
NS_OBJECT_ENSURE_REGISTERED (Limits);
TypeId
Limits::GetTypeId ()
{
static TypeId tid = TypeId ("ns3::ndn::Limits")
.SetGroupName ("Ndn")
.SetParent <Object> ()
.AddConstructor <Limits> ()
.AddAttribute ("ExpDecayTau", "Parameter 'tau' for the exponential delay of the current maximum limit variable",
TimeValue (Seconds (100.0)),
MakeTimeAccessor (&Limits::m_exponentialDecayTau),
MakeTimeChecker ()
)
.AddAttribute ("NonDecreasePeriod", "Only one decrease is allowed per one NonDecreasePeriod",
TimeValue (Seconds (0.1)),
MakeTimeAccessor (&Limits::m_nonDecreasePeriod),
MakeTimeChecker ()
)
.AddAttribute ("AdditiveIncrease", "Parameter for additive increase",
DoubleValue (1.0),
MakeDoubleAccessor (&Limits::m_additiveIncrease),
MakeDoubleChecker<double> ()
)
.AddAttribute ("MultiplicativeDecrease", "Parameter for multiplicative decrease",
DoubleValue (0.5),
MakeDoubleAccessor (&Limits::m_multiplicativeDecrease),
MakeDoubleChecker<double> ()
)
.AddTraceSource ("CurMaxLimit",
"Current maximum limit",
MakeTraceSourceAccessor (&Limits::m_curMaxLimit))
.AddTraceSource ("Outstanding",
"Number of outstanding interests",
MakeTraceSourceAccessor (&Limits::m_outstanding))
;
return tid;
}
void
Limits::SetMaxLimit (uint32_t max)
{
m_maxLimit = max;
m_curMaxLimit = max;
}
uint32_t
Limits::GetMaxLimit () const
{
return m_maxLimit;
}
void
Limits::DecayCurrentLimit ()
{
if (!IsEnabled ()) return;
if (!m_lastDecay.IsZero ())
{
double timeDiff = (Simulator::Now () - m_lastDecay).ToDouble (Time::S);
NS_LOG_DEBUG ("m_maxLimit - (m_maxLimit - m_curMaxLimit) * exp (-timeDiff / tau)");
NS_LOG_DEBUG (m_maxLimit << " - " << " ( " << m_maxLimit << " - " << (double)m_curMaxLimit << " ) " << " * " << " exp (- " << timeDiff << " / " << m_exponentialDecayTau.ToDouble (Time::S) << " ) ");
m_curMaxLimit = m_maxLimit - (m_maxLimit - m_curMaxLimit) * exp (-timeDiff / m_exponentialDecayTau.ToDouble (Time::S));
}
m_lastDecay = Simulator::Now ();
}
void
Limits::IncreaseLimit ()
{
if (!IsEnabled ()) return;
// Additive increase
m_curMaxLimit = std::min (1.0 * m_maxLimit,
(double)m_curMaxLimit + m_additiveIncrease / (double)m_curMaxLimit);
}
void
Limits::DecreaseLimit ()
{
if (!IsEnabled ()) return;
// m_curMaxLimit = std::max (0.0,
// (double)m_curMaxLimit - m_multiplicativeDecrease / (double)m_curMaxLimit);
// }
if (m_lastDecrease.IsZero () ||
(!m_lastDecrease.IsZero () && Simulator::Now () - m_lastDecrease > m_nonDecreasePeriod)) // allow
{
// Multiplicative decrease... almost
m_curMaxLimit = m_multiplicativeDecrease * m_curMaxLimit;
m_lastDecrease = Simulator::Now ();
}
}
bool
Limits::IsBelowLimit ()
{
if (!IsEnabled ()) return true;
if (m_curMaxLimit - m_outstanding >= 1.0)
{
// static UniformVariable acceptanceProbability (0, m_curMaxLimit);
// double value = acceptanceProbability.GetValue ();
double value = m_outstanding+ 1;
if (m_outstanding < value)
{
m_outstanding += 1.0;
return true;
}
else
return false;
// m_outstanding += 1;
// return true;
}
else
return false;
}
void
Limits::RemoveOutstanding ()
{
if (!IsEnabled ()) return; //limits are disabled
NS_LOG_DEBUG (m_outstanding);
NS_ASSERT_MSG (m_outstanding >= 1, "Should not be possible, unless we decreasing this number twice somewhere");
m_outstanding -= 1;
}
} // namespace ndn
} // namespace ns3