gridsim.net.fnb
Class RED

Object
  Thread
      Sim_entity
          FnbSCFQScheduler
              RED

All Implemented Interfaces:

PacketScheduler, Cloneable, Runnable

Direct Known Subclasses:

ARED

public class RED
extends FnbSCFQScheduler

This class implements the Random Early Detection (RED) policy for the management of netwrk buffers at routers. Its basic functionality is as follows:

• There is a RED object at each outport in routers.
• For each incoming packet that reaches that outport port, the policy decides whether it is enqueued or dropped. This is done by calculating the average buffer size and comparing it with two thresholds.
• If the packet is dropped, and it is not a junk packet, we must inform the user involved in the transmission about the dropping.

For more details, please refer to A. Caminero, A. Sulistio, B. Caminero, C. Carrion, and R. Buyya, Simulation of Buffer Management Policies in Networks for Grids, Proceedings of the 41th Annual Simulation Symposium (ANSS-41, IEEE CS Press, Los Alamitos, CA, USA), April 14-16, 2008, Ottawa, Canada.

Since:

GridSim Toolkit 4.2

Author:

Agustin Caminero

Nested Class Summary

Nested classes/interfaces inherited from class Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

RED(String name, double baudRate, int max_buf_size, double min_th, double max_th, double max_p, double queue_weight, boolean storeStats)
Creates a new SCFQ packet scheduler with the specified name and baud rate (in bits/sec).

Method Summary

double	avgQueueSize() Calculate the avg queue size for the RED algorithm.
Packet	deque() The method deque() has to decide which queue is to be served next.
boolean	enque(Packet pnp) Checks queue size and puts a packet into the queue
double	getAvg() Returns the AVG
double	getMaxP() Returns the MAX_P
double	getMaxTh() Returns the MAX_TH
double	getMinTh() Returns the MIN_TH
protected void	initialize() This function initializes the parameters of the buffers policies (RED, ARED)
boolean	setBaudRate(double rate) Sets the baud rate that this scheduler will be sending packets at.
void	setMaxP(double m) Updates the value of MAX_P
void	setMaxTh(double m) Updates the value of MAX_TH
void	setMinTh(double m) Updates the value of MIN_TH
void	setQueueWeight(double q) Updates the value of QUEUE_WEIGHT
void	updateStats() Update the statistics of this scheduler to a file.

Methods inherited from class FnbSCFQScheduler

body, checkDroppedGlList, getBaudRate, getCounterDroppedPkts, getMaxBufferSize, getMaxBufferSizeInPkts, getRouterID, getSchedID, getSchedName, increaseDroppedPktCounter, insertGlID_userID, insertPacketIntoQueue, isEmpty, makeRoomForPacket, pktListSize, resetCounterDroppedPkts, setBaudRateSCFQ, setMaxBufferSize, setRouterID, setWeights, size

Methods inherited from class Sim_entity

add_generator, add_param, add_port, clone, get_id, get_name, get_port, get_port, get_stat, run, send_on, set_invisible, set_stat, sim_cancel, sim_completed, sim_current, sim_get_next, sim_get_next, sim_hold_for, sim_hold, sim_pause_for, sim_pause_for, sim_pause_until, sim_pause_until, sim_pause, sim_process_for, sim_process_for, sim_process_until, sim_process_until, sim_process, sim_putback, sim_schedule, sim_schedule, sim_schedule, sim_schedule, sim_schedule, sim_schedule, sim_select, sim_trace, sim_wait_for, sim_wait_for, sim_wait_for, sim_wait, sim_waiting, sim_waiting

Methods inherited from class Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class Object

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

Constructor Detail

RED

public RED(String name,
           double baudRate,
           int max_buf_size,
           double min_th,
           double max_th,
           double max_p,
           double queue_weight,
           boolean storeStats)
    throws Exception

Creates a new SCFQ packet scheduler with the specified name and baud rate (in bits/sec). The name can be useful for debugging purposes, but serves no functional purposes.

Parameters:

name - Name of this scheduler

baudRate - baud rate in bits/s of the port that is using this scheduler.

max_buf_size - maximum buffer size for routers

min_th - minimum threshold for RED

max_th - maximum threshold for RED

max_p - maximum drop probability for RED

queue_weight - queue weight for RED

storeStats - whether we want to store stats or not

Throws:

Exception - This happens when the name is null or the baud rate <= 0

Pre Condition:

name != null, baudRate > 0

Post Condition:

$none

Method Detail

enque

public boolean enque(Packet pnp)

Checks queue size and puts a packet into the queue

Specified by:

enque in interface PacketScheduler

Specified by:

enque in class FnbSCFQScheduler

Parameters:

pnp - A Packet to be enqued by this scheduler.

Returns:

true if enqued, false otherwise

Pre Condition:

pnp != null

Post Condition:

$none

avgQueueSize

public double avgQueueSize()

Calculate the avg queue size for the RED algorithm.

Returns:

the avg queue size, which is calculated in this method

initialize

protected void initialize()

This function initializes the parameters of the buffers policies (RED, ARED)

Specified by:

initialize in class FnbSCFQScheduler

deque

public Packet deque()

The method deque() has to decide which queue is to be served next. In the original WFQ algorithm, this is always the packet with lowest finish time. We also need to update the CF (current finish no.) to that of the packet being served.

Specified by:

deque in interface PacketScheduler

Overrides:

deque in class FnbSCFQScheduler

Returns:

the packet to be sent out

Pre Condition:

$none

Post Condition:

$none

setBaudRate

public boolean setBaudRate(double rate)

Sets the baud rate that this scheduler will be sending packets at.

Parameters:

rate - the baud rate of this scheduler (in bits/s)

Returns:

true if the baud rate has been set properly, false otherwise

Pre Condition:

rate > 0

Post Condition:

$none

updateStats

public void updateStats()

Update the statistics of this scheduler to a file.
The file name is schedulerName_Buffers.csv.
The format is "Clock, MAX_P, MIN_TH, MAX_TH, AVG, QUEUE_SIZE"

Specified by:

updateStats in class FnbSCFQScheduler

getAvg

public double getAvg()

Returns the AVG

Specified by:

getAvg in class FnbSCFQScheduler

Returns:

the avg buffer size

getMaxP

public double getMaxP()

Returns the MAX_P

Returns:

the maximum dropping probability

setMaxP

public void setMaxP(double m)

Updates the value of MAX_P

Parameters:

m - new value for the maximum dropping probability

getMinTh

public double getMinTh()

Returns the MIN_TH

Returns:

the minimum threshold

getMaxTh

public double getMaxTh()

Returns the MAX_TH

Returns:

the maximum threshold

setQueueWeight

public void setQueueWeight(double q)

Updates the value of QUEUE_WEIGHT

Parameters:

q - new queue weight

setMinTh

public void setMinTh(double m)

Updates the value of MIN_TH

Parameters:

m - new minimum threshold

setMaxTh

public void setMaxTh(double m)

Updates the value of MAX_TH

Parameters:

m - new maximum threshold