net.i2p.router.transport.udp

Class SimpleBandwidthEstimator

java.lang.Object

net.i2p.router.transport.udp.SimpleBandwidthEstimator

All Implemented Interfaces:

BandwidthEstimator

class SimpleBandwidthEstimator
extends Object
implements BandwidthEstimator

A Westwood+ bandwidth estimator with: <ul> <li>A first-stage anti-aliasing low-pass filter based on RTT</li> <li>A time-varying EWMA filter based on inter-arrival time</li> </ul> <p>This estimator is adapted from the Linux kernel's <code>tcp_westwood.c</code> implementation and the Westwood+ research paper.</p> <p>Ref: <em>TCP Westwood: End-to-End Congestion Control for Wired/Wireless Networks</em> - Casetti et al.</p> <p>Ref: <em>End-to-End Bandwidth Estimation for Congestion Control in Packet Networks</em> - Grieco and Mascolo.</p> <p>Adapted for I2P streaming transport in 0.9.49.</p>

Constructor Summary

Constructors

Constructor and Description
SimpleBandwidthEstimator(I2PAppContext ctx, PeerState state) Creates a new bandwidth estimator for the given peer.

Method Summary

Modifier and Type	Method and Description
void	addSample(int acked) Records a new bandwidth sample based on the number of bytes acknowledged.
float	getBandwidthEstimate() Returns the current bandwidth estimate in bytes per millisecond.
float	getBandwidthEstimate(long now) Returns the current bandwidth estimate at the specified time.
String	toString() Returns a string representation of this estimator's current state.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleBandwidthEstimator

SimpleBandwidthEstimator(I2PAppContext ctx,
                         PeerState state)

Creates a new bandwidth estimator for the given peer.

Parameters:

ctx - I2P application context

state - peer state for RTT and other transport metrics

Method Detail

addSample

public void addSample(int acked)

Records a new bandwidth sample based on the number of bytes acknowledged.

Specified by:

addSample in interface BandwidthEstimator

Parameters:

acked - number of bytes newly acknowledged

getBandwidthEstimate

public float getBandwidthEstimate()

Returns the current bandwidth estimate in bytes per millisecond.

Specified by:

getBandwidthEstimate in interface BandwidthEstimator

Returns:

bandwidth estimate in bytes per millisecond

getBandwidthEstimate

public float getBandwidthEstimate(long now)

Returns the current bandwidth estimate at the specified time.

Parameters:

now - current time in milliseconds

Returns:

bandwidth estimate in bytes per millisecond

toString

public String toString()

Returns a string representation of this estimator's current state.

Overrides:

toString in class Object

Returns:

string representation