This class offers a data dissemination service using probabilistic broadcast. Each packet which arrives from upper layer or from the network is (re-)transmitted n times with n = floor(TTL/bcperiod) with probability beta. More...

#include <ProbabilisticBroadcast.h>

Inherits BaseNetwLayer.

Inherited by AdaptiveProbabilisticBroadcast.

Collaboration diagram for ProbabilisticBroadcast:

[legend]

List of all members.

Classes
struct	tMsgDesc
	Store messages in a structure so that we can keep some information needed by the protocol. More...
Public Member Functions
virtual void	initialize (int)
	Initialization of the module and some variables.
virtual void	finish ()
	Called when the simulation has finished.
Protected Types
enum	messagesTypes { UNKNOWN = 0, BROADCAST_TIMER, NEIGHBOR_TIMER, BETA_TIMER, DATA }
typedef struct ProbabilisticBroadcast::tMsgDesc	tMsgDesc
	Store messages in a structure so that we can keep some information needed by the protocol.
typedef set< unsigned int >	MsgIdSet
typedef multimap< simtime_t, tMsgDesc * >	TimeMsgMap
Protected Member Functions
virtual void	handleUpperMsg (cMessage *msg)
	Handle messages from upper layer.
virtual void	handleLowerMsg (cMessage *msg)
	Handle messages from lower layer.
virtual void	handleSelfMsg (cMessage *msg)
	Handle self messages.
virtual void	handleLowerControl (cMessage *msg)
	Handle control messages from lower layer.
virtual bool	messageKnown (unsigned int msgId)
	Checks whether a message is known (= kept in memory) or not.
virtual bool	debugMessageKnown (unsigned int msgId)
	Checks whether a message is known (= kept in memory) or not.
virtual void	insertMessage (simtime_t bcastDelay, tMsgDesc *msgDesc)
	Insert a message in both known ID list and message queue. If the message comes in front of the queue (i.e. it will be the next one to be broadcasted, the broadcastTimer is reset accordingly.
virtual tMsgDesc *	popFirstMessageUpdateQueue (void)
	Returns the descriptor of the first message in the queue, then remove its pointer from the queue and its id from the known IDs list. Then re-schedule the broadcastTimer to the broadcast instant of the new first element in the list.
virtual ProbabilisticBroadcastPkt *	encapsMsg (cMessage *msg)
	Returns a network layer packet which encapsulates the upper layer packet passed to the function.
virtual cMessage *	decapsMsg (ProbabilisticBroadcastPkt *msg)
	extracts and returns the application layer packet which is encapsulated in the network layer packet given in argument.
virtual void	insertNewMessage (ProbabilisticBroadcastPkt *pkt, bool iAmInitialSender=false)
	Insert a new message in both known ID list and message queue. The message comes either from upper layer or from lower layer. In both cases, it will be inserted in the queue with a broadcast attempt delay taken uniformly between 0 and min(broadcast period, TTL) in order to implement a random backoff for the first broadcast of a message.
Static Protected Member Functions
static long	getNextID ()
Protected Attributes
simtime_t	broadcastPeriod
	Period (in sim time) between two broadcast attempts. Read from omnetpp.ini.
double	beta
	Probability of each broadcast attempt. Read from omnetpp.ini.
simtime_t	timeToLive
int	maxNbBcast
	Maximal number of broadcast attempts for each packet. Read from omnetpp.ini.
int	maxFirstBcastBackoff
	Maximal back-off before first broadcast attempt [seconds]. Read from omnetpp.ini.
simtime_t	timeInQueueAfterDeath
	How long the message should be kept in queue after its died. That way the message is known if the node receives one of its copy that isn't dead because of TTL de-synchronization due to MAC backoff, propagation delay and clock drift. Read from omnetpp.ini.
int	headerLength
	Length of the NetwPkt header Read from omnetpp.ini.
bool	trace
bool	stats
bool	debug
	Debug switch for all other modules.
cMessage *	broadcastTimer
MsgIdSet	knownMsgIds
TimeMsgMap	msgQueue
MsgIdSet	debugMsgIdSet
int	convertedMacBroadcastAddr
long	nbDataPacketsReceived
long	nbDataPacketsSent
long	nbHops
int	debugNbMessageKnown
long	nbDataPacketsForwarded
cOutVector	oneHopLatencies
Static Protected Attributes
static long	id_counter = 0

Detailed Description

This class offers a data dissemination service using probabilistic broadcast. Each packet which arrives from upper layer or from the network is (re-)transmitted n times with n = floor(TTL/bcperiod) with probability beta.

Author:: Damien Piguet

Definition at line 36 of file ProbabilisticBroadcast.h.

Member Function Documentation

void ProbabilisticBroadcast::insertMessage	(	simtime_t	bcastDelay,
		tMsgDesc *	msgDesc
	)			`[protected, virtual]`

Insert a message in both known ID list and message queue. If the message comes in front of the queue (i.e. it will be the next one to be broadcasted, the broadcastTimer is reset accordingly.

Parameters:

	bcastDelay	relative (to now) simulator time of next broadcast attempt.
	msg	descriptor of the message to insert in the queue.

Definition at line 238 of file ProbabilisticBroadcast.cc.

References BaseNetwLayer::myNetwAddr.

Referenced by handleSelfMsg(), and insertNewMessage().

{
  TimeMsgMap::iterator pos;
  simtime_t bcastTime = simTime() + bcastDelay;

  EV << "PBr: " << simTime() << " n"  << myNetwAddr << "         insertMessage() bcastDelay = " << bcastDelay << " Msg ID = " << msgDesc->pkt->getId() << endl;
  // update TTL field of the message to the value it will have when taken out of the list
  msgDesc->pkt->setAppTtl(msgDesc->pkt->getAppTtl() - bcastDelay);
  // insert message ID in ID list.
  knownMsgIds.insert(msgDesc->pkt->getId());
  // insert key value pair <broadcast time, pointer to message> in message queue.
  pos = msgQueue.insert(make_pair(bcastTime, msgDesc));
  // if the message has been inserted in the front of the list, it means that it
  // will be the next message to be broadcasted, therefore we have to re-schedule
  // the broadcast timer to the message's broadcast instant.
  if (pos == msgQueue.begin()) {
    EV << "PBr: " << simTime() << " n"  << myNetwAddr << "         message inserted in the front, reschedule it." << endl;
    cancelEvent(broadcastTimer);
    scheduleAt(bcastTime, broadcastTimer);
  }
}

void ProbabilisticBroadcast::insertNewMessage	(	ProbabilisticBroadcastPkt *	pkt,
		bool	iAmInitialSender = `false`
	)			`[protected, virtual]`

Insert a new message in both known ID list and message queue. The message comes either from upper layer or from lower layer. In both cases, it will be inserted in the queue with a broadcast attempt delay taken uniformly between 0 and min(broadcast period, TTL) in order to implement a random backoff for the first broadcast of a message.

Parameters:

	msgDesc	descriptor of the message to insert in the queue.
	iAmInitialSender	message comes from upper layer, I am its creator and initial sender.

Definition at line 309 of file ProbabilisticBroadcast.cc.

References broadcastPeriod, insertMessage(), maxFirstBcastBackoff, and BaseNetwLayer::myNetwAddr.

Referenced by handleLowerMsg(), and handleUpperMsg().

{
  simtime_t ttl = pkt->getAppTtl();

  if (ttl > 0) {
    simtime_t bcastDelay;
    tMsgDesc* msgDesc;

    // insert packet in queue with delay in [0, min(TTL, broadcast period)].
    // since the insertion schedules the message for its first broadcast attempt,
    // we use a uniform random back-off taken between now and the broadcast delay
    // to avoid having all nodes in the neighborhood forward the packet at the same
    // time. Backoffs used at MAC layer are thought to be too short.
    if (broadcastPeriod < maxFirstBcastBackoff)
      bcastDelay = broadcastPeriod;
    else
      bcastDelay = maxFirstBcastBackoff;
    if (bcastDelay > ttl)
      bcastDelay = ttl;
    EV << "PBr: " << simTime() << " n"  << myNetwAddr << " insertNewMessage(): insert packet " << pkt->getId() << " with delay "
       << bcastDelay << endl;
    // create container for message and initialize container's values.
    msgDesc = new tMsgDesc;
    msgDesc->pkt = pkt;
    msgDesc->nbBcast = 0;  // so far, pkt has been forwarded zero times.
    msgDesc->initialSend = iAmInitialSender;
    debugMsgIdSet.insert(pkt->getId());
    insertMessage(uniform(0, bcastDelay), msgDesc);
  }
  else {
    EV << "PBr: " << simTime() << " n"  << myNetwAddr << " insertNewMessage(): got new packet with TTL = 0." << endl;
    delete pkt;
  }
}

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

modules/netw/ProbabilisticBroadcast.h
modules/netw/ProbabilisticBroadcast.cc

ProbabilisticBroadcast Class Reference [netwLayer - network layer modules]

Classes

Public Member Functions

Protected Types

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Member Function Documentation

ProbabilisticBroadcast Class Reference
[netwLayer - network layer modules]