wns::ldk::arq::SelectiveRepeat Class Reference

SelectiveRepeat implementation of the ARQ interface. More...

#include <ldk/arq/SelectiveRepeat.hpp>

Inheritance diagram for wns::ldk::arq::SelectiveRepeat:

Collaboration diagram for wns::ldk::arq::SelectiveRepeat:

List of all members.

Public Member Functions

void calculateSizes (const CommandPool *commandPool, Bit &commandPoolSize, Bit &sduSize) const

Calculate the sizes of the PDU.

virtual wns::ldk::CompoundPtr getACK ()

Return an acknowledgement Compound for transmission.

virtual wns::ldk::CompoundPtr getData ()

Return a user data Compound for transmission.

virtual const wns::ldk::CompoundPtr hasACK () const

Return an acknowledgement Compound that should be considered for transmission.

virtual bool hasCapacity () const

Return true, if the FunctionalUnit is still accepting compounds.

virtual const wns::ldk::CompoundPtr hasData () const

Return a user data Compound that should be considered for transmission.

virtual void onTimeout ()

Your callback. Implement this.

virtual void processIncoming (const CompoundPtr &compound)

Process compounds on uplink.

virtual void processOutgoing (const CompoundPtr &sdu)

Process compounds on downlink.

SelectiveRepeat (fun::FUN *fuNet, const wns::pyconfig::View &config)

~SelectiveRepeat ()

Protected Member Functions

virtual void doDelayDelivery ()

virtual void doDeliver ()

void keepSorted (const CompoundPtr &compound, CompoundContainer &conatiner)

void onACKFrame (const CompoundPtr &compound)

void onIFrame (const CompoundPtr &compound)

virtual bool onSuspend () const

void prepareRetransmission ()

void removeACKed (const CompoundPtr &ackCompound, CompoundContainer &container)

bool retransmissionState () const

Protected Attributes

wns::probe::bus::ContextCollectorPtr ackDelayProbeBus

CompoundContainer ackPDUs

list of ACK PDU to be sent.

CompoundPtr activeCompound

PDU to be sent.

int commandSize

Number of Bits the command occupies in the Commandpool.

bool delayingDelivery

ARQCommand::SequenceNumber LA

Sequence number of the last ACK received in order.

logger::Logger logger

ARQCommand::SequenceNumber NR

Sequence number of the last packet received in order.

ARQCommand::SequenceNumber NS

Sequence number of the last packet sent.

CompoundContainer receivedACKs

received out-of-sequence ACKs.

CompoundContainer receivedPDUs

received compounds.

double resendTimeout

Idle (no ACK) time after which sender enters retransmission state.

double retransmissionInterval

min time to be waiting between two retransmissions of the same packet.

wns::probe::bus::ContextCollectorPtr roundTripTimeProbeBus

bool sendNow

Remember to send the activeCompound.

CompoundContainer sentPDUs

The packets sent but not acknowledged yet.

int sequenceNumberSize

Divisor for Sequence Numbers.

CompoundContainer toRetransmit

List of packets to be retransmit.

wns::probe::bus::ContextCollectorPtr transmissionAttemptsProbeBus

probe to count the number of retransmissions needed. :TODO: this should go into the base class when the probe configuration works better.

int windowSize

Window size.

Private Types

typedef std::list< CompoundPtr > CompoundContainer

Friends

class tests::SelectiveRepeatTest

Detailed Description

This implementation was made according to the implementation of the SelectiveRepeat ARQ algorithm as described by Fred Halsall in "Data Communications, Computer Networks and open systems".

Note:: The mentioned implementation relies on the in-order delivery of ACKnowledgements. i.e. if an ACKnowledgement other than the next one expected is received by the Sender, a packet loss is considered to be the reason and the sender enters retransmission state. This makes this ARQ scheme unusable in applications where the in-order-delivery can not be guaranteed (e.g. in a TCP implementation). Consider using N-channel Stop and Wait in that case.
: the following modification has been made to make this implementation work in an environment where the Sender can receive the ACKs for multiple packets at the same point in time: If an out-of-sequence ACK arrives, previous (unacked) packets are only retransmitted if (a) they have not been retransmitted before or (b) the previous retransmission took place more than 2*minRTT ago. The minRTT is measured by the protocol itself.

Definition at line 129 of file SelectiveRepeat.hpp.

Member Typedef Documentation

typedef std::list<CompoundPtr> wns::ldk::arq::SelectiveRepeat::CompoundContainer [private]

Definition at line 139 of file SelectiveRepeat.hpp.

Constructor & Destructor Documentation

SelectiveRepeat::SelectiveRepeat	(	fun::FUN *	fuNet,
		const wns::pyconfig::View &	config
	)

Definition at line 50 of file SelectiveRepeat.cpp.

SelectiveRepeat::~SelectiveRepeat ( )

Definition at line 90 of file SelectiveRepeat.cpp.

Member Function Documentation

void SelectiveRepeat::calculateSizes	(	const CommandPool *	commandPool,
		Bit &	commandPoolSize,
		Bit &	dataSize
	)			const `[virtual]`

During size calculation, each FunctionalUnit is asked for the size of the PCI and SDU. Calculation begins with the layer the PDU last visited. To be able to calculate the sizes, a FunctionalUnit may in turn need to know the sizes as calculated by the FunctionalUnit right above itself.

It can do that by simply asking the CommandProxy, giving itself as questioner. The CommandProxy will then delegate the calculation request to the next higher FunctionalUnit in the path of the PDU.

Implements wns::ldk::CommandTypeSpecifierInterface.

Definition at line 446 of file SelectiveRepeat.cpp.

void SelectiveRepeat::doDelayDelivery ( ) [protected, virtual]

Implements wns::ldk::DelayedDeliveryInterface.

Definition at line 579 of file SelectiveRepeat.cpp.

void SelectiveRepeat::doDeliver ( ) [protected, virtual]

Implements wns::ldk::DelayedDeliveryInterface.

Definition at line 585 of file SelectiveRepeat.cpp.

wns::ldk::CompoundPtr SelectiveRepeat::getACK ( ) [virtual]

getACK will only get called after a call to hasACK. Every implementation of this interface /must/ return the same Compound for subsequent hasACK/getACK calls.

Implements wns::ldk::arq::ARQ.

Definition at line 167 of file SelectiveRepeat.cpp.

wns::ldk::CompoundPtr SelectiveRepeat::getData ( ) [virtual]

getData will only get called after a call to hasData. Every implementation of this interface /must/ return the same Compound for subsequent hasData/getData calls.

Implements wns::ldk::arq::ARQ.

Definition at line 183 of file SelectiveRepeat.cpp.

const wns::ldk::CompoundPtr SelectiveRepeat::hasACK ( ) const [virtual]

Every implementation should return CompoundPtr() in case there is no user data Compound scheduled for transmission.

Implements wns::ldk::arq::ARQ.

Definition at line 138 of file SelectiveRepeat.cpp.

bool SelectiveRepeat::hasCapacity ( ) const [virtual]

While hasCapacity returns false, processIncoming will never be called.

Implements wns::ldk::DelayedInterface.

Definition at line 102 of file SelectiveRepeat.cpp.

const wns::ldk::CompoundPtr SelectiveRepeat::hasData ( ) const [virtual]

Every implementation should return CompoundPtr() in case there is no user data Compound scheduled for transmission.

Implements wns::ldk::arq::ARQ.

Definition at line 150 of file SelectiveRepeat.cpp.

void SelectiveRepeat::keepSorted	(	const CompoundPtr &	compound,
		CompoundContainer &	conatiner
	)			`[protected]`

Definition at line 508 of file SelectiveRepeat.cpp.

void SelectiveRepeat::onACKFrame ( const CompoundPtr & compound ) [protected]

Definition at line 367 of file SelectiveRepeat.cpp.

void SelectiveRepeat::onIFrame ( const CompoundPtr & compound ) [protected]

Definition at line 284 of file SelectiveRepeat.cpp.

bool SelectiveRepeat::onSuspend ( ) const [protected, virtual]

Implements wns::ldk::SuspendSupport.

Definition at line 573 of file SelectiveRepeat.cpp.

void SelectiveRepeat::onTimeout ( ) [virtual]

The deriver is forced to implement this method. It gets called, whenever the timer fires.

Implements wns::events::CanTimeout.

Definition at line 249 of file SelectiveRepeat.cpp.

void SelectiveRepeat::prepareRetransmission ( ) [protected]

Definition at line 463 of file SelectiveRepeat.cpp.

void SelectiveRepeat::processIncoming ( const CompoundPtr & compound ) [virtual]

Override this method to handle incoming compounds.

Implements wns::ldk::DelayedInterface.

Definition at line 263 of file SelectiveRepeat.cpp.

void SelectiveRepeat::processOutgoing ( const CompoundPtr & ) [virtual]

Override this method to handle outgoing compounds.

Implements wns::ldk::DelayedInterface.

Definition at line 116 of file SelectiveRepeat.cpp.

void SelectiveRepeat::removeACKed	(	const CompoundPtr &	ackCompound,
		CompoundContainer &	container
	)			`[protected]`

Definition at line 537 of file SelectiveRepeat.cpp.

bool SelectiveRepeat::retransmissionState ( ) const [protected]

Definition at line 567 of file SelectiveRepeat.cpp.

Friends And Related Function Documentation

friend class tests::SelectiveRepeatTest [friend]

Definition at line 138 of file SelectiveRepeat.hpp.

Member Data Documentation

wns::probe::bus::ContextCollectorPtr wns::ldk::arq::SelectiveRepeat::ackDelayProbeBus [protected]

Definition at line 270 of file SelectiveRepeat.hpp.

CompoundContainer wns::ldk::arq::SelectiveRepeat::ackPDUs [protected]

Definition at line 235 of file SelectiveRepeat.hpp.

CompoundPtr wns::ldk::arq::SelectiveRepeat::activeCompound [protected]

Definition at line 220 of file SelectiveRepeat.hpp.

int wns::ldk::arq::SelectiveRepeat::commandSize [protected]

Definition at line 200 of file SelectiveRepeat.hpp.

bool wns::ldk::arq::SelectiveRepeat::delayingDelivery [protected]

Definition at line 273 of file SelectiveRepeat.hpp.

ARQCommand::SequenceNumber wns::ldk::arq::SelectiveRepeat::LA [protected]

Definition at line 215 of file SelectiveRepeat.hpp.

logger::Logger wns::ldk::arq::SelectiveRepeat::logger [protected]

Definition at line 275 of file SelectiveRepeat.hpp.

ARQCommand::SequenceNumber wns::ldk::arq::SelectiveRepeat::NR [protected]

Definition at line 210 of file SelectiveRepeat.hpp.

ARQCommand::SequenceNumber wns::ldk::arq::SelectiveRepeat::NS [protected]

Definition at line 205 of file SelectiveRepeat.hpp.

CompoundContainer wns::ldk::arq::SelectiveRepeat::receivedACKs [protected]

Definition at line 245 of file SelectiveRepeat.hpp.

CompoundContainer wns::ldk::arq::SelectiveRepeat::receivedPDUs [protected]

Definition at line 240 of file SelectiveRepeat.hpp.

double wns::ldk::arq::SelectiveRepeat::resendTimeout [protected]

Definition at line 256 of file SelectiveRepeat.hpp.

double wns::ldk::arq::SelectiveRepeat::retransmissionInterval [protected]

Definition at line 262 of file SelectiveRepeat.hpp.

wns::probe::bus::ContextCollectorPtr wns::ldk::arq::SelectiveRepeat::roundTripTimeProbeBus [protected]

Definition at line 271 of file SelectiveRepeat.hpp.

bool wns::ldk::arq::SelectiveRepeat::sendNow [protected]

Definition at line 250 of file SelectiveRepeat.hpp.

CompoundContainer wns::ldk::arq::SelectiveRepeat::sentPDUs [protected]

Definition at line 225 of file SelectiveRepeat.hpp.

int wns::ldk::arq::SelectiveRepeat::sequenceNumberSize [protected]

Definition at line 195 of file SelectiveRepeat.hpp.

CompoundContainer wns::ldk::arq::SelectiveRepeat::toRetransmit [protected]

Definition at line 230 of file SelectiveRepeat.hpp.

wns::probe::bus::ContextCollectorPtr wns::ldk::arq::SelectiveRepeat::transmissionAttemptsProbeBus [protected]

Definition at line 269 of file SelectiveRepeat.hpp.

int wns::ldk::arq::SelectiveRepeat::windowSize [protected]

Definition at line 190 of file SelectiveRepeat.hpp.

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

framework/library/src/ldk/arq/SelectiveRepeat.hpp
framework/library/src/ldk/arq/SelectiveRepeat.cpp


Public Member Functions
void	calculateSizes (const CommandPool *commandPool, Bit &commandPoolSize, Bit &sduSize) const
	Calculate the sizes of the PDU.
virtual wns::ldk::CompoundPtr	getACK ()
	Return an acknowledgement Compound for transmission.
virtual wns::ldk::CompoundPtr	getData ()
	Return a user data Compound for transmission.
virtual const wns::ldk::CompoundPtr	hasACK () const
	Return an acknowledgement Compound that should be considered for transmission.
virtual bool	hasCapacity () const
	Return true, if the FunctionalUnit is still accepting compounds.
virtual const wns::ldk::CompoundPtr	hasData () const
	Return a user data Compound that should be considered for transmission.
virtual void	onTimeout ()
	Your callback. Implement this.
virtual void	processIncoming (const CompoundPtr &compound)
	Process compounds on uplink.
virtual void	processOutgoing (const CompoundPtr &sdu)
	Process compounds on downlink.
	SelectiveRepeat (fun::FUN *fuNet, const wns::pyconfig::View &config)
	~SelectiveRepeat ()
Protected Member Functions
virtual void	doDelayDelivery ()
virtual void	doDeliver ()
void	keepSorted (const CompoundPtr &compound, CompoundContainer &conatiner)
void	onACKFrame (const CompoundPtr &compound)
void	onIFrame (const CompoundPtr &compound)
virtual bool	onSuspend () const
void	prepareRetransmission ()
void	removeACKed (const CompoundPtr &ackCompound, CompoundContainer &container)
bool	retransmissionState () const
Protected Attributes
wns::probe::bus::ContextCollectorPtr	ackDelayProbeBus
CompoundContainer	ackPDUs
	list of ACK PDU to be sent.
CompoundPtr	activeCompound
	PDU to be sent.
int	commandSize
	Number of Bits the command occupies in the Commandpool.
bool	delayingDelivery
ARQCommand::SequenceNumber	LA
	Sequence number of the last ACK received in order.
logger::Logger	logger
ARQCommand::SequenceNumber	NR
	Sequence number of the last packet received in order.
ARQCommand::SequenceNumber	NS
	Sequence number of the last packet sent.
CompoundContainer	receivedACKs
	received out-of-sequence ACKs.
CompoundContainer	receivedPDUs
	received compounds.
double	resendTimeout
	Idle (no ACK) time after which sender enters retransmission state.
double	retransmissionInterval
	min time to be waiting between two retransmissions of the same packet.
wns::probe::bus::ContextCollectorPtr	roundTripTimeProbeBus
bool	sendNow
	Remember to send the activeCompound.
CompoundContainer	sentPDUs
	The packets sent but not acknowledged yet.
int	sequenceNumberSize
	Divisor for Sequence Numbers.
CompoundContainer	toRetransmit
	List of packets to be retransmit.
wns::probe::bus::ContextCollectorPtr	transmissionAttemptsProbeBus
	probe to count the number of retransmissions needed. :TODO: this should go into the base class when the probe configuration works better.
int	windowSize
	Window size.
Private Types
typedef std::list< CompoundPtr >	CompoundContainer
Friends
class	tests::SelectiveRepeatTest