Random txt_time paket by packet in the link

["Tai Suk Kim" <kts@gigabitwireless.com>]

Dear NS-users,

 

I need to change the transmission time from a queue.

As the first step, i want to change it randomly (with distribution) packet by packet.

Later, i will do it from an input delay file.

 

For the random txt_time, i modified delay.cc and delay.h using delaymodel.* contributed

by Polly Huang. But it makes a core dumped error in

double txt = ranvar_->value();

 

Could you let me know what is wrong?

 

Thanks in advance.

 

Tai Suk Kim

 

my modification was as follows.

==================================================================

int LinkDelay::command(int argc, const char*const* argv)
{
        Tcl& tcl = Tcl::instance();
        if (argc == 3) {
                if (strcmp(argv[1], "ranvar") == 0) {
                        ranvar_ = (RandomVariable*) TclObject::lookup(argv[2]);
                        return (TCL_OK);
                } else if (strcmp(argv[1], "bandwidth") == 0) {
                        bandwidth_ = atof(argv[2]);
                        return (TCL_OK);
-------------------------------------------------------------               

 

}

class LinkDelay : public Connector {
 public:
        LinkDelay();
        void recv(Packet* p, Handler*);
        void send(Packet* p, Handler*);
        void handle(Event* e);
        double delay() { return delay_; }
        inline double txtime(Packet* p) {
                return (8. * hdr_cmn::access(p)->size() / bandwidth_);
        }
        inline double txtime2(Packet* p) {
                double txt = ranvar_->value();
                return txt;
                //return (8. * hdr_cmn::access(p)->size() / bandwidth_);
        }
        double bandwidth() const { return bandwidth_; }
        void pktintran(int src, int group);
 protected:
        int command(int argc, const char*const* argv);
        RandomVariable* ranvar_;

         void reset();
        double bandwidth_;      /* bandwidth of underlying link (bits/sec) */
        double delay_;          /* line latency */

        Event intr_;
        int dynamic_;           /* indicates whether or not link is ~ */

 

        PacketQueue* itq_;
        int total_[4];
};

 

void LinkDelay::recv(Packet* p, Handler* h)
{
        double txt = txtime2(p);

---------------------------------------------------------------------------       

 

}

 

in a tcl file,

 

set dm_ [new DelayLink]
set rv [new RandomVariable/Uniform]
$rv     set     min_ 0.
$rv     set     max_ 1.
$dm_ ranvar $rv