ndn::util::RttEstimator Class Reference

RTT/RTO estimator. More...

#include <rtt-estimator.hpp>

Inheritance diagram for ndn::util::RttEstimator:

Collaboration diagram for ndn::util::RttEstimator:

Classes
struct	Options

Public Member Functions
	RttEstimator (shared_ptr< const Options > options=nullptr)
	Constructor. More...
void	addMeasurement (time::nanoseconds rtt, size_t nExpectedSamples=1)
	Records a new RTT measurement. More...
bool	hasSamples () const
time::nanoseconds	getEstimatedRto () const
	Returns the estimated RTO value. More...
time::nanoseconds	getSmoothedRtt () const
	Returns the smoothed RTT value (SRTT). More...
time::nanoseconds	getRttVariation () const
	Returns the RTT variation (RTTVAR). More...
void	backoffRto ()
	Backoff RTO by a factor of Options::rtoBackoffMultiplier. More...

Protected Attributes
shared_ptr< const Options >	m_options

Detailed Description

RTT/RTO estimator.

This class implements the "Mean-Deviation" RTT estimator, as discussed in RFC 6298, with the modifications to RTO calculation described in RFC 7323 Appendix G.

Definition at line 41 of file rtt-estimator.hpp.

Constructor & Destructor Documentation

RttEstimator()

ndn::util::RttEstimator::RttEstimator ( shared_ptr< const Options >  options = nullptr )

explicit

Constructor.

Parameters

options

options for the estimator; if nullptr, a default set of options is used

Definition at line 32 of file rtt-estimator.cpp.

References m_options.

Member Function Documentation

addMeasurement()

void ndn::util::RttEstimator::addMeasurement	(	time::nanoseconds	rtt,
		size_t	nExpectedSamples = 1
	)

Records a new RTT measurement.

Parameters

rtt	the sampled RTT
nExpectedSamples	number of expected samples, must be greater than 0. It should be set to the current number of in-flight Interests. Please refer to Appendix G of RFC 7323 for details.

Note

Do not call this function with RTT samples from retransmitted Interests (per Karn's algorithm).

Definition at line 46 of file rtt-estimator.cpp.

References ndn::time::abs(), ns3::alpha, ndn::clamp(), hasSamples(), and m_options.

Referenced by ndn::util::RttEstimatorWithStats::addMeasurement(), nfd::face::LpReliability::processIncomingPacket(), and nfd::fw::asf::FaceInfo::recordRtt().

hasSamples()

bool ndn::util::RttEstimator::hasSamples ( ) const

inline

Definition at line 74 of file rtt-estimator.hpp.

Referenced by addMeasurement().

getEstimatedRto()

time::nanoseconds ndn::util::RttEstimator::getEstimatedRto ( ) const

inline

Returns the estimated RTO value.

Definition at line 83 of file rtt-estimator.hpp.

Referenced by nfd::face::LpReliability::handleOutgoing(), nfd::face::LpReliability::onLpPacketLost(), nfd::face::LpReliability::processIncomingPacket(), and nfd::fw::asf::FaceInfo::scheduleTimeout().

getSmoothedRtt()

time::nanoseconds ndn::util::RttEstimator::getSmoothedRtt ( ) const

inline

Returns the smoothed RTT value (SRTT).

Precondition

hasSamples() == true

Definition at line 93 of file rtt-estimator.hpp.

Referenced by nfd::fw::asf::FaceInfo::getSrtt().

getRttVariation()

time::nanoseconds ndn::util::RttEstimator::getRttVariation ( ) const

inline

Returns the RTT variation (RTTVAR).

Precondition

hasSamples() == true

Definition at line 103 of file rtt-estimator.hpp.

References backoffRto().

backoffRto()

void ndn::util::RttEstimator::backoffRto

(

)

Backoff RTO by a factor of Options::rtoBackoffMultiplier.

Definition at line 67 of file rtt-estimator.cpp.

References ndn::clamp(), and m_options.

Referenced by getRttVariation().

Member Data Documentation

m_options

shared_ptr<const Options> ndn::util::RttEstimator::m_options

protected

Definition at line 115 of file rtt-estimator.hpp.

Referenced by addMeasurement(), backoffRto(), and RttEstimator().

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The documentation for this class was generated from the following files:

• ndnSIM/ndn-cxx/ndn-cxx/util/rtt-estimator.hpp
• ndnSIM/ndn-cxx/ndn-cxx/util/rtt-estimator.cpp