io.aeron.driver.ext

Class CubicCongestionControl

java.lang.Object

io.aeron.driver.ext.CubicCongestionControl

All Implemented Interfaces:

CongestionControl, AutoCloseable

public class CubicCongestionControl
extends Object
implements CongestionControl

CUBIC congestion control manipulation of the receiver window length.

https://tools.ietf.org/id/draft-rhee-tcpm-cubic-02.txt and https://dl.acm.org/doi/10.1145/1400097.1400105

W_cubic = C(T - K)^3 + w_max

K = cbrt(w_max * B / C) w_max = window size before reduction T = time since last decrease

C = scaling constant (default 0.4) B = multiplicative decrease (default 0.2)

at MTU=4K, max window=128KB (w_max = 32 MTUs), then K ~= 2.5 seconds.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CC_PARAM_VALUE URI param value to identify this CongestionControl strategy.

Fields inherited from interface io.aeron.driver.CongestionControl

FORCE_STATUS_MESSAGE_BIT

Constructor Summary

Constructors

Constructor and Description
CubicCongestionControl(long registrationId, UdpChannel udpChannel, int streamId, int sessionId, int termLength, int senderMtuLength, InetSocketAddress controlAddress, InetSocketAddress sourceAddress, NanoClock nanoClock, MediaDriver.Context context, CountersManager countersManager) Construct a new CongestionControl instance for a received stream image using the Cubic algorithm.

Method Summary

Modifier and Type	Method and Description
void	close()
int	initialWindowLength() Called by DriverConductor to initialise window length for a new PublicationImage.
int	maxWindowLength() Called by DriverConductor limit the window length for a new PublicationImage.
void	onRttMeasurement(long nowNs, long rttNs, InetSocketAddress srcAddress) Called by Receiver on reception of an RTT Measurement.
void	onRttMeasurementSent(long nowNs) Called by Receiver to record that a measurement request has been sent.
long	onTrackRebuild(long nowNs, long newConsumptionPosition, long lastSmPosition, long hwmPosition, long startingRebuildPosition, long endingRebuildPosition, boolean lossOccurred) Called by DriverConductor upon execution of PublicationImage.trackRebuild(long) to pass on current status.
boolean	shouldMeasureRtt(long nowNs) Polled by Receiver to determine when to initiate an RTT measurement to a Sender.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.aeron.driver.CongestionControl

packOutcome, receiverWindowLength, shouldForceStatusMessage, threshold

Field Detail

CC_PARAM_VALUE

public static final String CC_PARAM_VALUE

URI param value to identify this CongestionControl strategy.

See Also:

Constant Field Values

Constructor Detail

CubicCongestionControl

public CubicCongestionControl(long registrationId,
                              UdpChannel udpChannel,
                              int streamId,
                              int sessionId,
                              int termLength,
                              int senderMtuLength,
                              InetSocketAddress controlAddress,
                              InetSocketAddress sourceAddress,
                              NanoClock nanoClock,
                              MediaDriver.Context context,
                              CountersManager countersManager)

Construct a new CongestionControl instance for a received stream image using the Cubic algorithm.

Parameters:

registrationId - for the publication image.

udpChannel - for the publication image.

streamId - for the publication image.

sessionId - for the publication image.

termLength - for the publication image.

senderMtuLength - for the publication image.

controlAddress - for the publication image.

sourceAddress - for the publication image.

nanoClock - for the precise timing.

context - for configuration options applied in the driver.

countersManager - for the driver.

Method Detail

close

public void close()

Specified by:

close in interface CongestionControl

Specified by:

close in interface AutoCloseable

shouldMeasureRtt

public boolean shouldMeasureRtt(long nowNs)

Polled by Receiver to determine when to initiate an RTT measurement to a Sender.

Specified by:

shouldMeasureRtt in interface CongestionControl

Parameters:

nowNs - in nanoseconds

Returns:

true for should measure RTT now or false for no measurement

onRttMeasurementSent

public void onRttMeasurementSent(long nowNs)

Called by Receiver to record that a measurement request has been sent.

Specified by:

onRttMeasurementSent in interface CongestionControl

Parameters:

nowNs - in nanoseconds.

onRttMeasurement

public void onRttMeasurement(long nowNs,
                             long rttNs,
                             InetSocketAddress srcAddress)

Called by Receiver on reception of an RTT Measurement.

Specified by:

onRttMeasurement in interface CongestionControl

Parameters:

nowNs - in nanoseconds

rttNs - to the Sender in nanoseconds

srcAddress - of the Sender

onTrackRebuild

public long onTrackRebuild(long nowNs,
                           long newConsumptionPosition,
                           long lastSmPosition,
                           long hwmPosition,
                           long startingRebuildPosition,
                           long endingRebuildPosition,
                           boolean lossOccurred)

Called by DriverConductor upon execution of PublicationImage.trackRebuild(long) to pass on current status.

The return value must be packed using CongestionControl.packOutcome(int, boolean).

Specified by:

onTrackRebuild in interface CongestionControl

Parameters:

nowNs - current time

newConsumptionPosition - of the subscribers

lastSmPosition - of the image

hwmPosition - of the image

startingRebuildPosition - of the rebuild

endingRebuildPosition - of the rebuild

lossOccurred - during rebuild

Returns:

outcome of congestion control calculation containing window length and whether to force sending an SM.

initialWindowLength

public int initialWindowLength()

Called by DriverConductor to initialise window length for a new PublicationImage.

Specified by:

initialWindowLength in interface CongestionControl

Returns:

initial window length for flow and congestion control.

maxWindowLength

public int maxWindowLength()

Called by DriverConductor limit the window length for a new PublicationImage.

Specified by:

maxWindowLength in interface CongestionControl

Returns:

maximum window length for flow and congestion control.