M/M/N queue simulation

Discussion in 'C' started by Idatriska, Aug 15, 2011.

  1. Idatriska

    Idatriska New Member

    Joined:
    Aug 15, 2011
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    Student
    Location:
    Indonesia
    Hi...my name is idatriska...anyone can help me...I have tried use code from Mr.adamms but it didn't work...somebody can help me
    this code for M/M/1 queue simulation,,,and i want to extend this code to be M/M/N queue simulation
    #include <stdio.h> #include <stdlib.h> #include <math.h> /*variables declaration*/ #define TOS 10 //termination of service; number of repetition for each experiment :100 #define MAXNOSRC 5 //number of sources #define MAXQSIZE 50 //max queue size or buffer #define ARRIVAL 0 //event type: arrival #define DEPARTURE 1 //event type: departure #define SERVER_IDLE 0 //data sink status: idle #define SERVER_BUSY 1 //data sink status: busy #define MAXNOE 20 //number of experiments double arrst[MAXNOSRC]; //arrival service time: stores the time each source will generate ‘a’ packet double patq[MAXQSIZE]; //packet arrival time in queue double dpst; //departure service time: store the time a packet will leave the server after being processed double iat; //inter arrival time (iat=1/λ) double st; //service time (st=1/µ) double simclock; //simulation clock double delay; //delay double tdelay; //total delay double avgdelay; //average delay= tdelay/npd double plr; //packet loss ratio=tpl/npa double smallest; //smallest simulation time double tqsize; double last_check; double load; //λ double npd; //# of packet departured/processed double npa; //# of packet arrive/generate double tpl; //total packet lost int dss; //data sink status (1: idle; 2: busy) int ssrc; //selected source int evtype; //event type (1: arrival; 2: departure) int cqsize; //current queue size int noe; //# of experiment /*functions prototype*/ double traffic(void); void init(void); void updateclock(void); void scheduler(void); void arrival(void); void departure(void); void result(void); int main(void); FILE *out_tdelay; //output file pointer for total delay: total_delay.csv FILE *out_avgdelay; //output file pointer for average delay: average_delay.csv FILE *out_plr; //output file pointer for packet loss ratio: packet_loss_ratio.csv double traffic(void) /*poisson distribution use to generate traffic*/ { double x=rand(); //get random # double iat=0; //initialize interAT=0 iat = -log(x/1.0e+30)/load; //formula to inject randomness into Poisson Distribution return iat; //return interAT to caller function } void init(void) { int a; load+=20; //increament load arrst[MAXNOSRC]=0.0; //arrival service time: stores the time each source will generate ‘a’ packet patq[MAXQSIZE]=0.0; //packet arrival time in queue for(a=0; a<MAXNOSRC; ++a) arrst[a]=rand(); //assign random start time to each arrival node==> how to get rand # between 0-1?? //arrst[0]=0.6; arrst[1]=0.5; arrst[2]=0.8; dpst=1.0e+30; //departure service time: store the time a packet will leave the server after being processed iat=0.0; st=2.5; //fix service time (st=1/µ == packet size/bandwidth) simclock=0.0; //simulation clock smallest=1.0e+30; //smallest simulation time avgdelay=0.0; //average delay= plr=0.0; //packet loss ratio tdelay=0.0; //total delay npd=0.0; //# of packet departured/sink npa=0.0; //# of packet arrived/generate tpl=0.0; //# of packet loss dss=SERVER_IDLE; //data sink status set to IDLE ssrc=0; //selected source evtype=1; //event type (1: arrival; 2: departure) cqsize=0; //current queue size/number in queue last_check=0.0; tqsize=0.0; } //end init void updateclock(void) /*Advance the simulation clock*/ { simclock=smallest; //assign current smallest time to simclock } void scheduler(void) /*Determine the event type of the next event to occur*/ { int a; smallest=1.0e+30; //assign very big number(infinity) to smallest time for(a=0; a<MAXNOSRC; ++a) //find the smallest among sources { if(arrst[a]<smallest) //if arrival start time[a] is less than smallest time { smallest=arrst[a]; //smallest become arrival start time for source [a] ssrc=a; //pick selected source evtype=ARRIVAL; //event type is ARRIVAL } if(dpst<smallest) //if departure start time is less than smallest time { smallest=dpst; //assign departure start time to smallest time evtype=DEPARTURE; //event type is DEPARTURE } } //end for } //end scheduler void arrival(void) { ++npa; //increament of packet generation/arrival iat=traffic(); //inter arrival time set to [-log(x/1.0+30)]/load; x is random # arrst[ssrc]=simclock+iat; if(dss==SERVER_IDLE) //if data sink status is IDLE 1 { dss=SERVER_BUSY; //change data sink status to BUSY 2 dpst=simclock+st; //schedule the time a task completely processed } else if(dss==SERVER_BUSY) //if data sink status is BUSY 2 { if(cqsize==MAXQSIZE) //if queue is full ++tpl; //increment total packet lost else if(cqsize<MAXQSIZE) //if queue space is still available { patq[cqsize]=simclock; //assign simclock to the time of current packet in queue ++cqsize; //increment current buffer in queue } //end else } //end elseif } //end arrival void departure(void) { int i; ++npd; //increment the number of task processed/packet departed if(cqsize==0) //if the buffer or queue is empty { dss=SERVER_IDLE; //no processsing dpst=1.0e+30; //assign very large value (infinity) to dpst } else if(cqsize!=0) //if there are packets in the queue { delay=simclock-patq[0]; //compute delay of packet who is beginning service tdelay+=delay; //update of total delay for(i=0; i<MAXQSIZE; ++i) patq=patq[i+1]; //move packet in queue up 1 place dpst=simclock+st; //departure start time --cqsize; //decreament number of packet in queue }//end elseif } //end departure void result(void) /*Compute and write estimates of desired measures of performance*/ { avgdelay=tdelay/npd; //to compute average delay plr=tpl/npa; //to compute packet loss ratio fprintf(out_tdelay,"%f\t%f\n",load, tdelay); fprintf(out_avgdelay,"%f\t%f\n",load, avgdelay); fprintf(out_plr,"%f\t%f\n",load, plr); } //end result int main(void) { out_tdelay=fopen("total_delay.csv","w"); out_avgdelay=fopen("average_delay.csv","w"); out_plr=fopen("packet_loss_ratio.csv","w"); for(noe=0; noe<MAXNOE; ++noe) //represent the repeatition of experiments { init(); //repeatition for one individually experiment while(npd<TOS) //TOS based on npd { scheduler(); //invoke scheduler function updateclock(); //invoke updateclock function if(evtype==ARRIVAL) arrival(); //invoke arrival function else if(evtype==DEPARTURE) departure(); //invoke departure function } //end while result(); //invoke result function } //end for fclose(out_tdelay); fclose(out_avgdelay); fclose(out_plr); system("wgnuplot simplot_tdelay.plt"); system("wgnuplot simplot_avgdelay.plt"); system("wgnuplot simplot_plr.plt"); return 0; } //end mainhow to extend this code????
     
  2. shabbir

    shabbir Administrator Staff Member

    Joined:
    Jul 12, 2004
    Messages:
    15,375
    Likes Received:
    388
    Trophy Points:
    83
    You probably missed the newlines everywhere in your post.
     
  3. Idatriska

    Idatriska New Member

    Joined:
    Aug 15, 2011
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    Student
    Location:
    Indonesia
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    
    /*variables declaration*/
    #define TOS 10 //termination of service; number of repetition for each experiment :100
    #define MAXNOSRC 5 //number of sources 
    #define MAXQSIZE 50 //max queue size or buffer 
    #define ARRIVAL 0 //event type: arrival
    #define DEPARTURE 1 //event type: departure
    #define SERVER_IDLE 0 //data sink status: idle
    #define SERVER_BUSY 1 //data sink status: busy
    #define MAXNOE 20 //number of experiments 
    
    double arrst[MAXNOSRC]; //arrival service time: stores the time each source will generate ‘a’ packet
    double patq[MAXQSIZE]; //packet arrival time in queue
    double dpst; //departure service time: store the time a packet will leave the server after being processed
    double iat; //inter arrival time (iat=1/?)
    double st; //service time (st=1/µ)
    double simclock; //simulation clock
    double delay; //delay
    double tdelay; //total delay
    double avgdelay; //average delay= tdelay/npd
    double plr; //packet loss ratio=tpl/npa
    double smallest; //smallest simulation time
    double tqsize;
    double last_check;
    
    double load; //?
    double npd; //# of packet departured/processed
    double npa; //# of packet arrive/generate
    double tpl; //total packet lost
    int dss; //data sink status (1: idle; 2: busy)
    int ssrc; //selected source
    int evtype; //event type (1: arrival; 2: departure)
    int cqsize; //current queue size
    int noe; //# of experiment
    
    /*functions prototype*/
    double traffic(void);
    void init(void);
    void updateclock(void);
    void scheduler(void);
    void arrival(void);
    void departure(void);
    void result(void);
    int main(void);
    
    FILE *out_tdelay; //output file pointer for total delay: total_delay.csv
    FILE *out_avgdelay; //output file pointer for average delay: average_delay.csv
    FILE *out_plr; //output file pointer for packet loss ratio: packet_loss_ratio.csv
    
    double traffic(void)
    /*poisson distribution use to generate traffic*/
    {
        double x=rand(); //get random #
        double iat=0; //initialize interAT=0
        iat = -log(x/1.0e+30)/load; //formula to inject randomness into Poisson Distribution
        return iat; //return interAT to caller function
    }
    
    void init(void)
    {
        int a; 
        load+=20; //increament load
    
        arrst[MAXNOSRC]=0.0; //arrival service time: stores the time each source will generate ‘a’ packet
        patq[MAXQSIZE]=0.0; //packet arrival time in queue
        for(a=0; a<MAXNOSRC; ++a)
            arrst[a]=rand(); //assign random start time to each arrival node==> how to get rand # between 0-1??
        //arrst[0]=0.6; arrst[1]=0.5; arrst[2]=0.8;
        dpst=1.0e+30; //departure service time: store the time a packet will leave the server after being processed
        iat=0.0;
        st=2.5; //fix service time (st=1/µ == packet size/bandwidth)
        simclock=0.0; //simulation clock
        smallest=1.0e+30; //smallest simulation time
        avgdelay=0.0; //average delay= 
        plr=0.0; //packet loss ratio
        tdelay=0.0; //total delay
        npd=0.0; //# of packet departured/sink
        npa=0.0; //# of packet arrived/generate
        tpl=0.0; //# of packet loss
        dss=SERVER_IDLE; //data sink status set to IDLE
        ssrc=0; //selected source
        evtype=1; //event type (1: arrival; 2: departure)
        cqsize=0; //current queue size/number in queue
        last_check=0.0;
        tqsize=0.0;
    } //end init
    
    void updateclock(void)
    /*Advance the simulation clock*/
    {
        simclock=smallest; //assign current smallest time to simclock
    }
    
    void scheduler(void)
    /*Determine the event type of the next event to occur*/
    {
        int a;
        smallest=1.0e+30; //assign very big number(infinity) to smallest time
        for(a=0; a<MAXNOSRC; ++a) //find the smallest among sources
        {
            if(arrst[a]<smallest) //if arrival start time[a] is less than smallest time
            {
                smallest=arrst[a]; //smallest become arrival start time for source [a]
                ssrc=a; //pick selected source 
                evtype=ARRIVAL; //event type is ARRIVAL
            }
            if(dpst<smallest) //if departure start time is less than smallest time
            {
                smallest=dpst; //assign departure start time to smallest time
                evtype=DEPARTURE; //event type is DEPARTURE
            }
        } //end for
    } //end scheduler
    
    void arrival(void)
    {
        ++npa; //increament of packet generation/arrival
        iat=traffic(); //inter arrival time set to [-log(x/1.0+30)]/load; x is random #
        arrst[ssrc]=simclock+iat;
        if(dss==SERVER_IDLE) //if data sink status is IDLE 1
        { 
            dss=SERVER_BUSY; //change data sink status to BUSY 2
            dpst=simclock+st;  //schedule the time a task completely processed
        }
        else if(dss==SERVER_BUSY) //if data sink status is BUSY 2
        { 
            if(cqsize==MAXQSIZE) //if queue is full
                ++tpl; //increment total packet lost
            else if(cqsize<MAXQSIZE) //if queue space is still available
            { 
                patq[cqsize]=simclock; //assign simclock to the time of current packet in queue 
                ++cqsize; //increment current buffer in queue
            } //end else
        } //end elseif
    } //end arrival
    
    void departure(void)
    {
        int i;
    
        ++npd; //increment the number of task processed/packet departed
        if(cqsize==0) //if the buffer or queue is empty
        { 
            dss=SERVER_IDLE; //no processsing
            dpst=1.0e+30; //assign very large value (infinity) to dpst
        }
        else if(cqsize!=0) //if there are packets in the queue
        {
            delay=simclock-patq[0]; //compute delay of packet who is beginning service
            tdelay+=delay; //update of total delay
            for(i=0; i<MAXQSIZE; ++i) 
                patq[i]=patq[i+1]; //move packet in queue up 1 place
            dpst=simclock+st; //departure start time
            --cqsize; //decreament number of packet in queue
        }//end elseif
    } //end departure
    
    void result(void)
    /*Compute and write estimates of desired measures of performance*/
    {    
        avgdelay=tdelay/npd; //to compute average delay
        plr=tpl/npa; //to compute packet loss ratio
        
        fprintf(out_tdelay,"%f\t%f\n",load, tdelay);
        fprintf(out_avgdelay,"%f\t%f\n",load, avgdelay);
        fprintf(out_plr,"%f\t%f\n",load, plr);
    } //end result
    
    int main(void)
    {    
        out_tdelay=fopen("total_delay.csv","w");
        out_avgdelay=fopen("average_delay.csv","w");
        out_plr=fopen("packet_loss_ratio.csv","w");
    
        for(noe=0; noe<MAXNOE; ++noe) //represent the repeatition of experiments
        {
            init();
            //repeatition for one individually experiment
            while(npd<TOS) //TOS based on npd 
            {
                scheduler(); //invoke scheduler function
                updateclock(); //invoke updateclock function
                if(evtype==ARRIVAL)
                    arrival(); //invoke arrival function
                else if(evtype==DEPARTURE)
                    departure(); //invoke departure function
            } //end while
            result(); //invoke result function
        } //end for
        fclose(out_tdelay);
        fclose(out_avgdelay);
        fclose(out_plr);
        system("wgnuplot simplot_tdelay.plt");
        system("wgnuplot simplot_avgdelay.plt");
        system("wgnuplot simplot_plr.plt");
        return 0;
    } //end main
    
    [CO#include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    
    /*variables declaration*/
    #define TOS 10 //termination of service; number of repetition for each experiment :100
    #define MAXNOSRC 5 //number of sources 
    #define MAXQSIZE 50 //max queue size or buffer 
    #define ARRIVAL 0 //event type: arrival
    #define DEPARTURE 1 //event type: departure
    #define SERVER_IDLE 0 //data sink status: idle
    #define SERVER_BUSY 1 //data sink status: busy
    #define MAXNOE 20 //number of experiments 
    
    double arrst[MAXNOSRC]; //arrival service time: stores the time each source will generate ‘a’ packet
    double patq[MAXQSIZE]; //packet arrival time in queue
    double dpst; //departure service time: store the time a packet will leave the server after being processed
    double iat; //inter arrival time (iat=1/?)
    double st; //service time (st=1/µ)
    double simclock; //simulation clock
    double delay; //delay
    double tdelay; //total delay
    double avgdelay; //average delay= tdelay/npd
    double plr; //packet loss ratio=tpl/npa
    double smallest; //smallest simulation time
    double tqsize;
    double last_check;
    
    double load; //?
    double npd; //# of packet departured/processed
    double npa; //# of packet arrive/generate
    double tpl; //total packet lost
    int dss; //data sink status (1: idle; 2: busy)
    int ssrc; //selected source
    int evtype; //event type (1: arrival; 2: departure)
    int cqsize; //current queue size
    int noe; //# of experiment
    
    /*functions prototype*/
    double traffic(void);
    void init(void);
    void updateclock(void);
    void scheduler(void);
    void arrival(void);
    void departure(void);
    void result(void);
    int main(void);
    
    FILE *out_tdelay; //output file pointer for total delay: total_delay.csv
    FILE *out_avgdelay; //output file pointer for average delay: average_delay.csv
    FILE *out_plr; //output file pointer for packet loss ratio: packet_loss_ratio.csv
    
    double traffic(void)
    /*poisson distribution use to generate traffic*/
    {
        double x=rand(); //get random #
        double iat=0; //initialize interAT=0
        iat = -log(x/1.0e+30)/load; //formula to inject randomness into Poisson Distribution
        return iat; //return interAT to caller function
    }
    
    void init(void)
    {
        int a; 
        load+=20; //increament load
    
        arrst[MAXNOSRC]=0.0; //arrival service time: stores the time each source will generate ‘a’ packet
        patq[MAXQSIZE]=0.0; //packet arrival time in queue
        for(a=0; a<MAXNOSRC; ++a)
            arrst[a]=rand(); //assign random start time to each arrival node==> how to get rand # between 0-1??
        //arrst[0]=0.6; arrst[1]=0.5; arrst[2]=0.8;
        dpst=1.0e+30; //departure service time: store the time a packet will leave the server after being processed
        iat=0.0;
        st=2.5; //fix service time (st=1/µ == packet size/bandwidth)
        simclock=0.0; //simulation clock
        smallest=1.0e+30; //smallest simulation time
        avgdelay=0.0; //average delay= 
        plr=0.0; //packet loss ratio
        tdelay=0.0; //total delay
        npd=0.0; //# of packet departured/sink
        npa=0.0; //# of packet arrived/generate
        tpl=0.0; //# of packet loss
        dss=SERVER_IDLE; //data sink status set to IDLE
        ssrc=0; //selected source
        evtype=1; //event type (1: arrival; 2: departure)
        cqsize=0; //current queue size/number in queue
        last_check=0.0;
        tqsize=0.0;
    } //end init
    
    void updateclock(void)
    /*Advance the simulation clock*/
    {
        simclock=smallest; //assign current smallest time to simclock
    }
    
    void scheduler(void)
    /*Determine the event type of the next event to occur*/
    {
        int a;
        smallest=1.0e+30; //assign very big number(infinity) to smallest time
        for(a=0; a<MAXNOSRC; ++a) //find the smallest among sources
        {
            if(arrst[a]<smallest) //if arrival start time[a] is less than smallest time
            {
                smallest=arrst[a]; //smallest become arrival start time for source [a]
                ssrc=a; //pick selected source 
                evtype=ARRIVAL; //event type is ARRIVAL
            }
            if(dpst<smallest) //if departure start time is less than smallest time
            {
                smallest=dpst; //assign departure start time to smallest time
                evtype=DEPARTURE; //event type is DEPARTURE
            }
        } //end for
    } //end scheduler
    
    void arrival(void)
    {
        ++npa; //increament of packet generation/arrival
        iat=traffic(); //inter arrival time set to [-log(x/1.0+30)]/load; x is random #
        arrst[ssrc]=simclock+iat;
        if(dss==SERVER_IDLE) //if data sink status is IDLE 1
        { 
            dss=SERVER_BUSY; //change data sink status to BUSY 2
            dpst=simclock+st;  //schedule the time a task completely processed
        }
        else if(dss==SERVER_BUSY) //if data sink status is BUSY 2
        { 
            if(cqsize==MAXQSIZE) //if queue is full
                ++tpl; //increment total packet lost
            else if(cqsize<MAXQSIZE) //if queue space is still available
            { 
                patq[cqsize]=simclock; //assign simclock to the time of current packet in queue 
                ++cqsize; //increment current buffer in queue
            } //end else
        } //end elseif
    } //end arrival
    
    void departure(void)
    {
        int i;
    
        ++npd; //increment the number of task processed/packet departed
        if(cqsize==0) //if the buffer or queue is empty
        { 
            dss=SERVER_IDLE; //no processsing
            dpst=1.0e+30; //assign very large value (infinity) to dpst
        }
        else if(cqsize!=0) //if there are packets in the queue
        {
            delay=simclock-patq[0]; //compute delay of packet who is beginning service
            tdelay+=delay; //update of total delay
            for(i=0; i<MAXQSIZE; ++i) 
                patq[i]=patq[i+1]; //move packet in queue up 1 place
            dpst=simclock+st; //departure start time
            --cqsize; //decreament number of packet in queue
        }//end elseif
    } //end departure
    
    void result(void)
    /*Compute and write estimates of desired measures of performance*/
    {    
        avgdelay=tdelay/npd; //to compute average delay
        plr=tpl/npa; //to compute packet loss ratio
        
        fprintf(out_tdelay,"%f\t%f\n",load, tdelay);
        fprintf(out_avgdelay,"%f\t%f\n",load, avgdelay);
        fprintf(out_plr,"%f\t%f\n",load, plr);
    } //end result
    
    int main(void)
    {    
        out_tdelay=fopen("total_delay.csv","w");
        out_avgdelay=fopen("average_delay.csv","w");
        out_plr=fopen("packet_loss_ratio.csv","w");
    
        for(noe=0; noe<MAXNOE; ++noe) //represent the repeatition of experiments
        {
            init();
            //repeatition for one individually experiment
            while(npd<TOS) //TOS based on npd 
            {
                scheduler(); //invoke scheduler function
                updateclock(); //invoke updateclock function
                if(evtype==ARRIVAL)
                    arrival(); //invoke arrival function
                else if(evtype==DEPARTURE)
                    departure(); //invoke departure function
            } //end while
            result(); //invoke result function
        } //end for
        fclose(out_tdelay);
        fclose(out_avgdelay);
        fclose(out_plr);
        system("wgnuplot simplot_tdelay.plt");
        system("wgnuplot simplot_avgdelay.plt");
        system("wgnuplot simplot_plr.plt");
        return 0;
    } //end main
     
    Last edited by a moderator: Aug 15, 2011
  4. Idatriska

    Idatriska New Member

    Joined:
    Aug 15, 2011
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    0
    Occupation:
    Student
    Location:
    Indonesia
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    
    /*variables declaration*/
    #define TOS 10 //termination of service; number of repetition for each experiment :100
    #define MAXNOSRC 5 //number of sources 
    #define MAXQSIZE 50 //max queue size or buffer 
    #define ARRIVAL 0 //event type: arrival
    #define DEPARTURE 1 //event type: departure
    #define SERVER_IDLE 0 //data sink status: idle
    #define SERVER_BUSY 1 //data sink status: busy
    #define MAXNOE 20 //number of experiments 
    
    double arrst[MAXNOSRC]; //arrival service time: stores the time each source will generate ‘a’ packet
    double patq[MAXQSIZE]; //packet arrival time in queue
    double dpst; //departure service time: store the time a packet will leave the server after being processed
    double iat; //inter arrival time (iat=1/?)
    double st; //service time (st=1/µ)
    double simclock; //simulation clock
    double delay; //delay
    double tdelay; //total delay
    double avgdelay; //average delay= tdelay/npd
    double plr; //packet loss ratio=tpl/npa
    double smallest; //smallest simulation time
    double tqsize;
    double last_check;
    
    double load; //?
    double npd; //# of packet departured/processed
    double npa; //# of packet arrive/generate
    double tpl; //total packet lost
    int dss; //data sink status (1: idle; 2: busy)
    int ssrc; //selected source
    int evtype; //event type (1: arrival; 2: departure)
    int cqsize; //current queue size
    int noe; //# of experiment
    
    /*functions prototype*/
    double traffic(void);
    void init(void);
    void updateclock(void);
    void scheduler(void);
    void arrival(void);
    void departure(void);
    void result(void);
    int main(void);
    
    FILE *out_tdelay; //output file pointer for total delay: total_delay.csv
    FILE *out_avgdelay; //output file pointer for average delay: average_delay.csv
    FILE *out_plr; //output file pointer for packet loss ratio: packet_loss_ratio.csv
    
    double traffic(void)
    /*poisson distribution use to generate traffic*/
    {
        double x=rand(); //get random #
        double iat=0; //initialize interAT=0
        iat = -log(x/1.0e+30)/load; //formula to inject randomness into Poisson Distribution
        return iat; //return interAT to caller function
    }
    
    void init(void)
    {
        int a; 
        load+=20; //increament load
    
        arrst[MAXNOSRC]=0.0; //arrival service time: stores the time each source will generate ‘a’ packet
        patq[MAXQSIZE]=0.0; //packet arrival time in queue
        for(a=0; a<MAXNOSRC; ++a)
            arrst[a]=rand(); //assign random start time to each arrival node==> how to get rand # between 0-1??
        //arrst[0]=0.6; arrst[1]=0.5; arrst[2]=0.8;
        dpst=1.0e+30; //departure service time: store the time a packet will leave the server after being processed
        iat=0.0;
        st=2.5; //fix service time (st=1/µ == packet size/bandwidth)
        simclock=0.0; //simulation clock
        smallest=1.0e+30; //smallest simulation time
        avgdelay=0.0; //average delay= 
        plr=0.0; //packet loss ratio
        tdelay=0.0; //total delay
        npd=0.0; //# of packet departured/sink
        npa=0.0; //# of packet arrived/generate
        tpl=0.0; //# of packet loss
        dss=SERVER_IDLE; //data sink status set to IDLE
        ssrc=0; //selected source
        evtype=1; //event type (1: arrival; 2: departure)
        cqsize=0; //current queue size/number in queue
        last_check=0.0;
        tqsize=0.0;
    } //end init
    
    void updateclock(void)
    /*Advance the simulation clock*/
    {
        simclock=smallest; //assign current smallest time to simclock
    }
    
    void scheduler(void)
    /*Determine the event type of the next event to occur*/
    {
        int a;
        smallest=1.0e+30; //assign very big number(infinity) to smallest time
        for(a=0; a<MAXNOSRC; ++a) //find the smallest among sources
        {
            if(arrst[a]<smallest) //if arrival start time[a] is less than smallest time
            {
                smallest=arrst[a]; //smallest become arrival start time for source [a]
                ssrc=a; //pick selected source 
                evtype=ARRIVAL; //event type is ARRIVAL
            }
            if(dpst<smallest) //if departure start time is less than smallest time
            {
                smallest=dpst; //assign departure start time to smallest time
                evtype=DEPARTURE; //event type is DEPARTURE
            }
        } //end for
    } //end scheduler
    
    void arrival(void)
    {
        ++npa; //increament of packet generation/arrival
        iat=traffic(); //inter arrival time set to [-log(x/1.0+30)]/load; x is random #
        arrst[ssrc]=simclock+iat;
        if(dss==SERVER_IDLE) //if data sink status is IDLE 1
        { 
            dss=SERVER_BUSY; //change data sink status to BUSY 2
            dpst=simclock+st;  //schedule the time a task completely processed
        }
        else if(dss==SERVER_BUSY) //if data sink status is BUSY 2
        { 
            if(cqsize==MAXQSIZE) //if queue is full
                ++tpl; //increment total packet lost
            else if(cqsize<MAXQSIZE) //if queue space is still available
            { 
                patq[cqsize]=simclock; //assign simclock to the time of current packet in queue 
                ++cqsize; //increment current buffer in queue
            } //end else
        } //end elseif
    } //end arrival
    
    void departure(void)
    {
        int i;
    
        ++npd; //increment the number of task processed/packet departed
        if(cqsize==0) //if the buffer or queue is empty
        { 
            dss=SERVER_IDLE; //no processsing
            dpst=1.0e+30; //assign very large value (infinity) to dpst
        }
        else if(cqsize!=0) //if there are packets in the queue
        {
            delay=simclock-patq[0]; //compute delay of packet who is beginning service
            tdelay+=delay; //update of total delay
            for(i=0; i<MAXQSIZE; ++i) 
                patq[i]=patq[i+1]; //move packet in queue up 1 place
            dpst=simclock+st; //departure start time
            --cqsize; //decreament number of packet in queue
        }//end elseif
    } //end departure
    
    void result(void)
    /*Compute and write estimates of desired measures of performance*/
    {    
        avgdelay=tdelay/npd; //to compute average delay
        plr=tpl/npa; //to compute packet loss ratio
        
        fprintf(out_tdelay,"%f\t%f\n",load, tdelay);
        fprintf(out_avgdelay,"%f\t%f\n",load, avgdelay);
        fprintf(out_plr,"%f\t%f\n",load, plr);
    } //end result
    
    int main(void)
    {    
        out_tdelay=fopen("total_delay.csv","w");
        out_avgdelay=fopen("average_delay.csv","w");
        out_plr=fopen("packet_loss_ratio.csv","w");
    
        for(noe=0; noe<MAXNOE; ++noe) //represent the repeatition of experiments
        {
            init();
            //repeatition for one individually experiment
            while(npd<TOS) //TOS based on npd 
            {
                scheduler(); //invoke scheduler function
                updateclock(); //invoke updateclock function
                if(evtype==ARRIVAL)
                    arrival(); //invoke arrival function
                else if(evtype==DEPARTURE)
                    departure(); //invoke departure function
            } //end while
            result(); //invoke result function
        } //end for
        fclose(out_tdelay);
        fclose(out_avgdelay);
        fclose(out_plr);
        system("wgnuplot simplot_tdelay.plt");
        system("wgnuplot simplot_avgdelay.plt");
        system("wgnuplot simplot_plr.plt");
        return 0;
    } //end main
    How to extend this code to M/M/N queue simulation..???
     
    Last edited by a moderator: Aug 15, 2011
  5. xpi0t0s

    xpi0t0s Mentor

    Joined:
    Aug 6, 2004
    Messages:
    3,009
    Likes Received:
    203
    Trophy Points:
    63
    Occupation:
    Senior Support Engineer
    Location:
    England
    If you wrote that code you would be able to figure it out.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice