io.aeron.driver.ext

Class CubicCongestionControl

java.lang.Object

io.aeron.driver.ext.CubicCongestionControl

All Implemented Interfaces:

CongestionControl, java.lang.AutoCloseable

public class CubicCongestionControl
extends java.lang.Object
implements CongestionControl

CUBIC congestion control manipulation of the receiver window length.

https://research.csc.ncsu.edu/netsrv/?q=content/bic-and-cubic

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.

Method Summary

Modifier and Type	Method and Description
void	close()
int	initialWindowLength() Called by DriverConductor to initialise window length for a new PublicationImage.
void	onRttMeasurement(long nowNs, long rttNs, java.net.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, 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

Method Detail

shouldMeasureRtt

public boolean shouldMeasureRtt(long nowNs)

Description copied from interface: CongestionControl

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)

Description copied from interface: CongestionControl

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,
                             java.net.InetSocketAddress srcAddress)

Description copied from interface: CongestionControl

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)

Description copied from interface: CongestionControl

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

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

Specified by:

onTrackRebuild in interface CongestionControl

Parameters:

nowNs - in nanoseconds

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()

Description copied from interface: CongestionControl

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

Specified by:

initialWindowLength in interface CongestionControl

Returns:

new image window length

close

public void close()

Specified by:

close in interface CongestionControl

Specified by:

close in interface java.lang.AutoCloseable