How to measure the queue length in the base station or mobile node?

1. modify queue/priqueue.h

#include "trace.h"

class PriQueue : public DropTail {

public:

PriQueue();

int command(int argc, const char*const* argv);

void recv(Packet *p, Handler *h);

void recvHighPriority(Packet *, Handler *);

// insert packet at front of queue

void filter(PacketFilter filter, void * data);

// apply filter to each packet in queue,

// - if filter returns 0 leave packet in queue

// - if filter returns 1 remove packet from queue

Packet* filter(nsaddr_t id);

void Terminate(void);

//added by smallko

Tcl_Channel tchan_; /* place to write trace records */

TracedInt curq_; /* current qlen seen by arrivals */

void trace(TracedVar*); /* routine to write trace records */

…………………….

1. modify queue/ priqueue.cc

PriQueue::PriQueue() : DropTail()

{

bind("curq_",&curq_);

tchan_=0;

bind("Prefer_Routing_Protocols", &Prefer_Routing_Protocols);

LIST_INSERT_HEAD(&prhead, this, link);

}

void PriQueue::recv(Packet *p, Handler *h)

{

struct hdr_cmn *ch = HDR_CMN(p);

curq_ = q_->length();

if(Prefer_Routing_Protocols) {

……………………………

}

void PriQueue::trace(TracedVar* v)

{

char wrk[500], *p;

if (((p = strstr(v->name(), "curq")) == NULL) ) {

fprintf(stderr, "PriQueue:unknown trace var %s\n", v->name());

return;

}

if (tchan_) {

int n;

double t = Scheduler::instance().clock();

if (strstr(v->name(), "curq") != NULL) {

sprintf(wrk, "Q %g %d", t, int(*((TracedInt*) v)));

}

n = strlen(wrk);

wrk[n] = '\n';

wrk[n+1] = 0;

(void)Tcl_Write(tchan_, wrk, n+1);

}

return;

}

2. modify tcl/lib/ns-default.tcl

add “Queue/DropTail/PriQueue set curq_ 0“

3. make clean ; make

4. modify the tcl script file (I use a simple example to demonstrate how to measure the queue length in the base station.)

............................................................................................

set opt(chan) Channel/WirelessChannel ;# channel type

set opt(prop) Propagation/TwoRayGround ;# radio-propagation model

set opt(netif) Phy/WirelessPhy ;# network interface type

set opt(mac) Mac/802_11 ;# MAC type

set opt(ifq) Queue/DropTail/PriQueue ;# interface queue type

set opt(ifqlen) 50

set opt(ll) LL ;# link layer type

set opt(ant) Antenna/OmniAntenna ;# antenna model

set opt(adhocRouting) DSDV ;# routing protocol

set opt(x) 500 ;# X dimension of the topography

set opt(y) 500 ;# Y dimension of the topography

............................................................................................

set chan [new $opt(chan)]

set topo [new Topography]

$topo load_flatgrid $opt(x) $opt(y)

$ns node-config -adhocRouting $opt(adhocRouting) \

-llType $opt(ll) \

-macType $opt(mac) \

-ifqType $opt(ifq) \

-ifqLen $opt(ifqlen) \

-antType $opt(ant) \

-propType $opt(prop) \

-phyType $opt(netif) \

-channel $chan \

-topoInstance $topo \

-wiredRouting ON \

-agentTrace OFF \

-routerTrace OFF \

-macTrace OFF \

-movementTrace OFF

set BS(0) [$ns node 1.0.0]

$BS(0) random-motion 0

set bs_ifq [$BS(0) set ifq_(0)]

set queuechan [open qlen.tr w]

$bs_ifq trace curq_

$bs_ifq attach $queuechan
............................................................................................

5. After simulation, you will find a file “qlen.tr”. In it, you can observe the queue length variation.

Reference : Smallko