ds.funnel.traffic.component.timedistribution

Class BurstyTimeDistribution

java.lang.Object

ds.funnel.traffic.component.timedistribution.BurstyTimeDistribution

All Implemented Interfaces:

PacketTimeDistribution

public class BurstyTimeDistribution
extends java.lang.Object
implements PacketTimeDistribution

BurstyTimeDistribution defines a 'bursty' packet distribution. The distribution maintains some base packet distribution during 'normal' or 'non-bursty' intervals, interspersed with periods of increased packet rates during bursts.

A BurstyTimeDistribution is specified in terms of several base time distributions:

• A base rate distribution: this dictates the distribution of packet transmissions over time during the normal flow
• A burst duration distribution: this dictates the distribution of the length of bursts over time
• A burst spacing distribution: this dictates the distribution of the gaps between bursts over time; equivalently, the distribution of the length of non-bursty intervals over time

A bursty time distribution requires one additional parameter, a double, percent increase during bursts, which specifies how much the packet rates will increase during bursty intervals. This percentage increase will be applied to the rates generated by the base rate distribution, so that the distribution during bursty intervals will be the same type as the normal flow, but packets will be sent at higher rates.

Author:

Kira Lindburg

Constructor Summary

Constructors

Constructor and Description
BurstyTimeDistribution(PacketTimeDistribution baseRateDistribution, double percentIncreaseDuringBursts, PacketTimeDistribution burstDurationDistribution, PacketTimeDistribution burstSpacingDistribution)

Method Summary

Modifier and Type	Method and Description
PacketTimeDistribution	getBaseRateDistribution()
PacketTimeDistribution	getBurstDurationDistribution()
PacketTimeDistribution	getBurstSpacingDistribution()
double	getPercentIncreaseDuringBursts() Initializes the bursty rate distribution to a brand new RandomTimeDistribution with bounds calculated from the current base rate distribution's bounds and the current value of percent increase during bursts.
int	getType()
int	nextInterval()
int[]	prediction(int size) Generates an array containing predicted packet transmission times, in terms of number of ms from this instant.
void	setBaseRateDistribution(PacketTimeDistribution baseRateDistribution)
void	setBurstDurationDistribution(PacketTimeDistribution burstDurationDistribution)
void	setBurstSpacingDistribution(PacketTimeDistribution burstSpacingDistribution)
void	setPercentIncreaseDuringBursts(double percentIncrease) Sets the percentage increase of packet transmissions during bursts for this bursty time distribution.

Methods inherited from class java.lang.Object

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

Constructor Detail

BurstyTimeDistribution

public BurstyTimeDistribution(PacketTimeDistribution baseRateDistribution,
                              double percentIncreaseDuringBursts,
                              PacketTimeDistribution burstDurationDistribution,
                              PacketTimeDistribution burstSpacingDistribution)

Method Detail

getBaseRateDistribution

public PacketTimeDistribution getBaseRateDistribution()

setBaseRateDistribution

public void setBaseRateDistribution(PacketTimeDistribution baseRateDistribution)

getBurstDurationDistribution

public PacketTimeDistribution getBurstDurationDistribution()

setBurstDurationDistribution

public void setBurstDurationDistribution(PacketTimeDistribution burstDurationDistribution)

getBurstSpacingDistribution

public PacketTimeDistribution getBurstSpacingDistribution()

setBurstSpacingDistribution

public void setBurstSpacingDistribution(PacketTimeDistribution burstSpacingDistribution)

setPercentIncreaseDuringBursts

public void setPercentIncreaseDuringBursts(double percentIncrease)

Sets the percentage increase of packet transmissions during bursts for this bursty time distribution. The packet transmission rates during bursts will be adjusted according to rate*(1 + percentIncrease).

Parameters:

percentIncrease - the desired percentage increase of packet transmissions during bursts, as a decimal. Should be a value in (0.0, 1.0]. A percent increase of eg .5 would specify that packet transmission rates during bursts are 150% of the base rates (between bursts).

getPercentIncreaseDuringBursts

public double getPercentIncreaseDuringBursts()

Initializes the bursty rate distribution to a brand new RandomTimeDistribution with bounds calculated from the current base rate distribution's bounds and the current value of percent increase during bursts.

getType

public int getType()

Specified by:

getType in interface PacketTimeDistribution

Returns:

an integer id number specifying the type of distribution. This should be a unique identifier for the type of time distribution generated by a given PacketTimeDistribution.

nextInterval

public int nextInterval()

Specified by:

nextInterval in interface PacketTimeDistribution

Returns:

an interval, in ms, to wait before the next packet should be sent following this distribution

prediction

public int[] prediction(int size)

Description copied from interface: PacketTimeDistribution

Generates an array containing predicted packet transmission times, in terms of number of ms from this instant.

Specified by:

prediction in interface PacketTimeDistribution

Parameters:

size - the number of predictions contained in the returned array

Returns:

a prediction for the base rate distribution; does not account for bursts