ratecontrolledscheduler.java

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/*
 * ** Network and Service Differentiation Extensions to GridSim 3.0 **
 *
 * Gokul Poduval & Chen-Khong Tham
 * Computer Communication Networks (CCN) Lab
 * Dept of Electrical & Computer Engineering
 * National University of Singapore
 * August 2004
 *
 * Licence: GPL - http://www.gnu.org/copyleft/gpl.html
 *
 * RateControlledScheduler.java - Implements a Rate controlled scheduler
 *
 */

package gridsim.net;

import gridsim.net.*;
import eduni.simjava.*;
import gridsim.*;
import java.util.*;


/**
 * RateControlledScheduler is an implementation of a rate-jitter controlling
 * regulator. For more details refer to <b>H. Zhang and D.Ferrari's</b>
 * INFOCOM '93 paper <i>Rate-Controlled Static-Priority Queueing</i>.
 * <p>
 * RateControlledScheduler can be used to control the bandwidth that
 * is assigned to each class of user at a Router. This is a non-work conserving
 * algorithm, which means that the router can remain idle even if there are
 * packets in its queue.
 * <p>
 * At a RateControlledScheduler each class of users is assigned a certain
 * percentage of bandwidth, and the scheduler makes sure that each class remains
 * constrained within its bandwidth limits at all times.
 *
 * @author Gokul Poduval & Chen-Khong Tham, National University of Singapore
 * @since  GridSim Toolkit 4.0
 * @invariant $none
 */
public class RateControlledScheduler extends Sim_entity
                                     implements PacketScheduler
{
    private double baudRate_;       // baud rate of a link
    private int routerID_ ;         // router ID that hosts this scheduler
    private double[] rates_;        // rates of each class
    private int numClasses_;        // num of classes or ToS
    private ArrayList[] packets_;   // intermediate queue
    private ArrayList pktList_;     // final queue
    private ArrayList classType_;   // an integer storing the class types

    private static final int BITS = 8;     // 1 byte in bits
    private static final int DEQUEUE_PACKET = 1000;
    private static final int INTERNAL_DEQUEUE = 1001;


    /**
     * Creates a new RateControlled packet scheduler with the specified name
     * and baud rate (in bits/s).
     * The name can be useful for debugging purposes, but serves
     * no functional purposes.
     * Don't forget to set the rate for each packet class by using the
     * {@link #setRates(double[])} method.
     *
     * @param name       Name of this scheduler
     * @param baudRate   baud rate in bits/s of the port that is using
     *                   this scheduler.
     * @param numClasses number of classes for prioritizing a packet
     * @throws ParameterException This happens when the name is null or
     *                   the baud rate <= 0 or num of classes <= 0
     * @pre name != null
     * @pre baudRate > 0
     * @pre numClasses > 0
     * @post $none
     */
    public RateControlledScheduler(String name, double baudRate, int numClasses)
                         throws ParameterException
    {
        super(name);
        if (baudRate <= 0) {
            throw new ParameterException("Baudrate must be greater than 0");
        }

        if (numClasses <= 0) {
            throw new ParameterException("Num of class must be greater than 0");
        }

        routerID_ = -1;
        baudRate_ = baudRate;
        numClasses_ = numClasses;
        init(numClasses);
    }

    /**
     * Creates a new RateControlled packet scheduler with the specified name.
     * The baud rate is left at 0, and should be set with
     * {@link gridsim.net.PacketScheduler#setBaudRate(double)}
     * before the simulation starts.
     * The name can be useful for debugging purposes, but serves
     * no functional purposes.
     * Don't forget to set the rate for each packet class by using the
     * {@link #setRates(double[])} method.
     *
     * @param name       Name of this scheduler
     * @param numClasses number of classes for prioritizing a packet
     * @throws ParameterException This happens when the name is null or
     *                   the baud rate <= 0 or num of classes <= 0
     * @pre name != null
     * @pre numClasses > 0
     * @post $none
     */
    public RateControlledScheduler(String name, int numClasses)
                                   throws ParameterException
    {
        super(name);
        if (numClasses <= 0) {
            throw new ParameterException("Num of class must be greater than 0");
        }

        routerID_ = -1;
        baudRate_ = 0;
        numClasses_ = numClasses;
        init(numClasses);
    }

    /**
     * Creates a new RateControlled packet scheduler with the specified name
     * and baud rate (in bits/s).
     * The name can be useful for debugging purposes, but serves
     * no functional purposes.
     * Don't forget to set the rate for each packet class by using the
     * {@link #setRates(double[])} method.
     *
     * @param name       Name of this scheduler
     * @param baudRate   baud rate in bits/s of the port that is using
     *                   this scheduler.
     * @param routerID   the router ID that hosts this packet scheduler
     * @param numClasses number of classes for prioritizing a packet
     * @throws ParameterException This happens when the name is null or
     *                   router ID <= 0 or the baud rate <= 0 or
     *                   num of classes <= 0
     * @pre name != null
     * @pre baudRate > 0
     * @pre routerID > 0
     * @pre numClasses > 0
     * @post $none
     */
    public RateControlledScheduler(String name, double baudRate, int routerID,
                                   int numClasses) throws ParameterException
    {
        super(name);
        if (baudRate <= 0) {
            throw new ParameterException("Baud rate must be greater than 0");
        }

        if (routerID <= 0) {
            throw new ParameterException("Router ID must be greater than 0");
        }

        if (numClasses <= 0) {
            throw new ParameterException("Num of class must be greater than 0");
        }

        baudRate_ = baudRate;
        routerID_ = routerID;
        numClasses_ = numClasses;
        init(numClasses);
    }

    /**
     * Initializes all private attributes
     * @param numClasses    number of classes for prioritizing a packet
     * @pre $none
     * @post $none
     */
    private void init(int numClasses)
    {
        rates_ = null;
        classType_ = new ArrayList(numClasses);
        packets_ = new ArrayList[numClasses];
        pktList_ = new ArrayList();

        for (int i = 0; i < numClasses; i++)
        {
            packets_[i] = new ArrayList();
            classType_.add( new Integer(i) );
        }
    }

    /**
     * Gets the number of classes for prioritizing incoming packets
     * @return number of classes
     * @pre $none
     * @post $none
     */
    public int getNumClass() {
        return numClasses_;
    }

    /**
     * Gets the list of rates for each packet class
     * @return the list of rates or <tt>null</tt> if empty
     * @pre $none
     * @post $none
     */
    public double[] getRate() {
        return rates_;
    }

    /**
     * Handles an incoming events coming from a specified Router
     * @pre $none
     * @post $none
     */
    public void body()
    {
        Sim_event ev = new Sim_event();
        while ( Sim_system.running() )
        {
            super.sim_get_next(ev);     // get the incoming event

            // if the simulation finishes then exit the loop
            if (ev.get_tag() == GridSimTags.END_OF_SIMULATION) {
                break;
            }

            // process the received event
            processEvent(ev);
        }
    }

    /**
     * Processes an incoming event based on its tag name
     * @param ev  a Sim_event object
     * @pre ev != null
     * @post $none
     */
    private void processEvent(Sim_event ev)
    {
        if (ev == null) {
            return;
        }

        switch (ev.get_tag())
        {
            case GridSimTags.SCHEDULER_ENQUE:
                this.enque(ev);
                break;

            case INTERNAL_DEQUEUE:
                this.internalDequeue(ev);
                break;

            case DEQUEUE_PACKET:
                this.dequeue(ev);
                break;

            default:
                System.out.println(super.get_name() +
                        ".processEvent: Warning - unknown tag name.");
                break;
        }
    }

    /**
     * In this scheduler, the packet is put into the tail of the queue.
     * There is no buffer management, so packets are never dropped, and the
     * queue can grow as long as system memory is available.
     *
     * @param ev    a Sim_event object
     * @pre ev != null
     * @post $none
     */
    private void enque(Sim_event ev)
    {
        if (ev == null) {
            return;
        }

        try
        {
            Packet pkt = (Packet) ev.get_data();
            int type = pkt.getNetServiceType();

            // check whether the class type is correct or not
            if (type >= packets_.length)
            {