cbr_traffic.cc

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


/* 
 * Constant bit rate traffic source.   Parameterized by interval, (optional)
 * random noise in the interval, and packet size.  
 */

class CBR_Traffic : public TrafficGenerator {
 public:
    CBR_Traffic();
    virtual double next_interval(int&);
    //HACK so that udp agent knows interpacket arrival time within a burst
    inline double interval() { return (interval_); }
 protected:
    virtual void start();
    void init();
    double rate_;     /* send rate during on time (bps) */
    double interval_; /* packet inter-arrival time during burst (sec) */
    double random_;
    int seqno_;
    int maxpkts_;
};


static class CBRTrafficClass : public TclClass {
 public:
    CBRTrafficClass() : TclClass("Application/Traffic/CBR") {}
    TclObject* create(int, const char*const*) {
        return (new CBR_Traffic());
    }
} class_cbr_traffic;

CBR_Traffic::CBR_Traffic() : seqno_(0)
{
    bind_bw("rate_", &rate_);
    bind("random_", &random_);
    bind("packetSize_", &size_);
    bind("maxpkts_", &maxpkts_);
}

void CBR_Traffic::init()
{
        // compute inter-packet interval 
    interval_ = (double)(size_ << 3)/(double)rate_;
    if (agent_)
        if (agent_->get_pkttype() != PT_TCP &&
            agent_->get_pkttype() != PT_TFRC)
            agent_->set_pkttype(PT_CBR);
}

void CBR_Traffic::start()
{
        init();
        running_ = 1;
        timeout();
}

double CBR_Traffic::next_interval(int& size)
{
    // Recompute interval in case rate_ or size_ has changes
    interval_ = (double)(size_ << 3)/(double)rate_;
    double t = interval_;
    if (random_)
        t += interval_ * Random::uniform(-0.5, 0.5);    
    size = size_;
    if (++seqno_ < maxpkts_)
        return(t);
    else
        return(-1); 
}

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