EtherBus Class Reference

List of all members.

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Detailed Description

Implements the bus which connects hosts, switches and other LAN entities on an Ethernet LAN.

Public Member Functions
	EtherBus ()
virtual	~EtherBus ()
Protected Member Functions
virtual void	initialize ()
virtual void	handleMessage (cMessage *)
virtual void	finish ()
void	tokenize (const char *str, std::vector< double > &array)
Private Attributes
double	propagationSpeed
BusTap *	tap
int	taps
long	numMessages

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Constructor & Destructor Documentation

EtherBus::EtherBus (   )

{ tap = NULL; }

EtherBus::~EtherBus (   )  [virtual]

{ delete [] tap; }

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Member Function Documentation

void EtherBus::finish (   )  [protected, virtual]

{ if (par("writeScalars").boolValue()) { double t = simTime(); recordScalar("simulated time", t); recordScalar("messages handled", numMessages); if (t>0) recordScalar("messages/sec", numMessages/t); } }

void EtherBus::handleMessage (  cMessage *   )  [protected, virtual]

{ if (!msg->isSelfMessage()) { // Handle frame sent down from the network entity int tapPoint = msg->arrivalGate()->index(); EV << "Frame " << msg << " arrived on tap " << tapPoint << endl; // create upstream and downstream events if (tapPoint>0) { // start UPSTREAM travel cMessage *event = new cMessage("upstream", UPSTREAM); event->setContextPointer(&tap[tapPoint-1]); // if goes downstream too, we need to make a copy cMessage *msg2 = (tapPoint<taps-1) ? (cMessage *)msg->dup() : msg; event->encapsulate(msg2); scheduleAt(simTime()+tap[tapPoint].propagationDelay[UPSTREAM], event); } if (tapPoint<taps-1) { // start DOWNSTREAM travel cMessage *event = new cMessage("downstream", DOWNSTREAM); event->setContextPointer(&tap[tapPoint+1]); event->encapsulate(msg); scheduleAt(simTime()+tap[tapPoint].propagationDelay[DOWNSTREAM], event); } if (taps==1) { // if there's only one tap, there's nothing to do delete msg; } } else { // handle upstream and downstream events int direction = msg->kind(); BusTap *thistap = (BusTap *) msg->contextPointer(); int tapPoint = thistap->id; EV << "Event " << msg << " on tap " << tapPoint << ", sending out frame\n"; // send out on gate bool isLast = (direction==UPSTREAM) ? (tapPoint==0) : (tapPoint==taps-1); cMessage *msg2 = isLast ? msg->decapsulate() : (cMessage *)msg->encapsulatedMsg()->dup(); send(msg2, "out", tapPoint); // if not end of the bus, schedule for next tap if (isLast) { EV << "End of bus reached\n"; delete msg; } else { EV << "Scheduling for next tap\n"; int nextTap = (direction==UPSTREAM) ? (tapPoint-1) : (tapPoint+1); msg->setContextPointer(&tap[nextTap]); scheduleAt(simTime()+tap[tapPoint].propagationDelay[direction], msg); } } }

void EtherBus::initialize (   )  [protected, virtual]

{ numMessages = 0; WATCH(numMessages); propagationSpeed = par("propagationSpeed").doubleValue(); // initialize the positions where the hosts connects to the bus taps = gate("in",0)->size(); if (gate("out",0)->size()!=taps) error("the sizes of the in[] and out[] gate vectors must be the same"); // read positions and check if positions are defined in order (we're lazy to sort...) std::vector<double> pos; tokenize(par("positions").stringValue(), pos); int numPos = pos.size(); if (numPos>taps) EV << "Note: `positions' parameter contains more values ("<< numPos << ") than " "the number of taps (" << taps << "), ignoring excess values.\n"; else if (numPos<taps && numPos>=2) EV << "Note: `positions' parameter contains less values ("<< numPos << ") than " "the number of taps (" << taps << "), repeating distance between last 2 positions.\n"; else if (numPos<taps && numPos<2) EV << "Note: `positions' parameter contains too few values, using 5m distances.\n"; tap = new BusTap[taps]; int i; double distance = numPos>=2 ? pos[numPos-1]-pos[numPos-2] : 5; for (i=0; i<taps; i++) { tap[i].id = i; tap[i].position = i<numPos ? pos[i] : i==0 ? 5 : tap[i-1].position+distance; } for (i=0; i<taps-1; i++) { if (tap[i].position > tap[i+1].position) error("Tap positions must be ordered in ascending fashion, modify 'positions' parameter and rerun\n"); } // Calculate propagation of delays between tap points on the bus for (i=0; i<taps; i++) { // Propagation delay between adjacent tap points if (i == 0) { tap[i].propagationDelay[UPSTREAM] = 0; tap[i].propagationDelay[DOWNSTREAM] = (tap[i+1].position - tap[i].position)/propagationSpeed; } else if (i == taps-1) { tap[i].propagationDelay[UPSTREAM] = tap[i-1].propagationDelay[DOWNSTREAM]; tap[i].propagationDelay[DOWNSTREAM] = 0; } else { tap[i].propagationDelay[UPSTREAM] = tap[i-1].propagationDelay[DOWNSTREAM]; tap[i].propagationDelay[DOWNSTREAM] = (tap[i+1].position - tap[i].position)/propagationSpeed;; } } // Prints out data of parameters for parameter checking... EV << "Parameters of (" << className() << ") " << fullPath() << "\n"; EV << "propagationSpeed: " << propagationSpeed << "\n"; for (i=0; i<taps; i++) { EV << "tap[" << i << "] pos: " << tap[i].position << " upstream delay: " << tap[i].propagationDelay[UPSTREAM] << " downstream delay: " << tap[i].propagationDelay[DOWNSTREAM] << endl; } EV << "\n"; // autoconfig: tell everyone that bus supports only 10Mb half-duplex EV << "Autoconfig: advertising that we only support 10Mb half-duplex operation\n"; for (i=0; i<taps; i++) { EtherAutoconfig *autoconf = new EtherAutoconfig("autoconf-10Mb-halfduplex"); autoconf->setHalfDuplex(true); autoconf->setTxrate(10000000); // 10Mb send(autoconf,"out",i); } }

void EtherBus::tokenize (  const char *  str, std::vector< double > &  array )  [protected]

{ char *str2 = opp_strdup(str); if (!str2) return; char *s = strtok(str2, " "); while (s) { array.push_back(atof(s)); s = strtok(NULL, " "); } delete [] str2; }

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Member Data Documentation

long EtherBus::numMessages [private]

double EtherBus::propagationSpeed [private]

BusTap* EtherBus::tap [private]

int EtherBus::taps [private]

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The documentation for this class was generated from the following file:

• EtherBus.cc

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