expoo.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (c) Xerox Corporation 1997. All rights reserved.
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 * General Public License for more details.
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 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/tools/expoo.cc,v 1.15 2005/08/26 05:05:30 tomh Exp $ (Xerox)";
#endif

#include <stdlib.h>
 
#include "random.h"
#include "trafgen.h"
#include "ranvar.h"


/* implement an on/off source with exponentially distributed on and
 * off times.  parameterized by average burst time, average idle time,
 * burst rate and packet size.
 */

class EXPOO_Traffic : public TrafficGenerator {
 public:
    EXPOO_Traffic();
    virtual double next_interval(int&);
        virtual void timeout();
    // Added by Debojyoti Dutta October 12th 2000
    int command(int argc, const char*const* argv);
 protected:
    void init();
    double ontime_;   /* average length of burst (sec) */
    double offtime_;  /* average length of idle time (sec) */
    double rate_;     /* send rate during on time (bps) */
    double interval_; /* packet inter-arrival time during burst (sec) */
    unsigned int rem_; /* number of packets left in current burst */

    /* new stuff using RandomVariable */
    ExponentialRandomVariable burstlen_;
    ExponentialRandomVariable Offtime_;

};


static class EXPTrafficClass : public TclClass {
 public:
    EXPTrafficClass() : TclClass("Application/Traffic/Exponential") {}
    TclObject* create(int, const char*const*) {
        return (new EXPOO_Traffic());
    }
} class_expoo_traffic;

// Added by Debojyoti Dutta October 12th 2000
// This is a new command that allows us to use 
// our own RNG object for random number generation
// when generating application traffic

int EXPOO_Traffic::command(int argc, const char*const* argv){
        
        if(argc==3){
                if (strcmp(argv[1], "use-rng") == 0) {
                        burstlen_.seed((char *)argv[2]);
                        Offtime_.seed((char *)argv[2]);
                        return (TCL_OK);
                }
        }
        return Application::command(argc,argv);
}


EXPOO_Traffic::EXPOO_Traffic() : burstlen_(0.0), Offtime_(0.0)
{
    bind_time("burst_time_", &ontime_);
    bind_time("idle_time_", Offtime_.avgp());
    bind_bw("rate_", &rate_);
    bind("packetSize_", &size_);
}

void EXPOO_Traffic::init()
{
        /* compute inter-packet interval during bursts based on
     * packet size and burst rate.  then compute average number
     * of packets in a burst.
     */
    interval_ = (double)(size_ << 3)/(double)rate_;
    burstlen_.setavg(ontime_/interval_);
    rem_ = 0;
    if (agent_)
        agent_->set_pkttype(PT_EXP);
}

double EXPOO_Traffic::next_interval(int& size)
{
    double t = interval_;

    if (rem_ == 0) {
        /* compute number of packets in next burst */
        rem_ = int(burstlen_.value() + .5);
        /* make sure we got at least 1 */
        if (rem_ == 0)
            rem_ = 1;
        /* start of an idle period, compute idle time */
        t += Offtime_.value();
    }   
    rem_--;

    size = size_;
    return(t);
}

void EXPOO_Traffic::timeout()
{
    if (! running_)
        return;

    /* send a packet */
    // The test tcl/ex/test-rcvr.tcl relies on the "NEW_BURST" flag being 
    // set at the start of any exponential burst ("talkspurt").  
    if (nextPkttime_ != interval_ || nextPkttime_ == -1) 
        agent_->sendmsg(size_, "NEW_BURST");
    else 
        agent_->sendmsg(size_);
    /* figure out when to send the next one */
    nextPkttime_ = next_interval(size_);
    /* schedule it */
    if (nextPkttime_ > 0)
        timer_.resched(nextPkttime_);
}

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