Package: inet.networklayer.probabilistic

ProbabilisticBroadcast

simple module

Multi-hop ad-hoc data dissemination protocol based on probabilistic broadcast.

This method reduces the number of packets sent on the channel (reducing the broadcast storm problem) at the risk of some nodes not receiving the data. It is particularly interesting for mobile networks. Parameter maxNbBcast sets the maximum number of broadcast transmissions of a packet, parameter beta gives the transmission probability for each attempt, parameter bcperiod sets the time between two transmission attempts. Parameter maxFirstBcastBackoff sets a backoff window before first transmission attempt, and parameter timeInQueueAfterDeath sets the time during which a node remembers a packet whose time to live (TTL) expired, avoiding retransmitting it in case it comes back in the network because of some problem.

Inheritance diagram

The following diagram shows inheritance relationships for this type. Unresolved types are missing from the diagram.

Known subclasses

Name	Type	Description
AdaptiveProbabilisticBroadcast	simple module	Multi-hop ad-hoc data dissemination protocol based on probabilistic broadcast, with adaptive parameters.

Extends

Name	Type	Description
NetworkProtocolBase	simple module	Module base for different network protocols.

Parameters

Name	Type	Default value	Description
interfaceTableModule	string
headerLength	int	96b	length of the network packet header (in bits)
bcperiod	double	2 s	period between two probabilistic broadcast attempts
beta	double	0.8	probability of broadcast for each attempt
maxNbBcast	int	1	maximal number of broadcast attempts for each packet.
maxFirstBcastBackoff	double	1 s	maximal back-off before first broadcast attempt [seconds]. if don't want to use this parameter, simply set it to a value that is greater than bcperiod.
timeToLive	double	10 s
timeInQueueAfterDeath	double	60 s	How many seconds 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.

Properties

Name	Value	Description
display	i=block/fork
class	ProbabilisticBroadcast

Gates

Name	Direction	Size	Description
transportIn	input
transportOut	output
queueIn	input
queueOut	output

Signals

Name	Type	Unit
packetReceivedFromUpper	cPacket
packetReceivedFromLower	cPacket
packetDropped	cPacket
packetSentToLower	cPacket
packetSentToUpper	cPacket

Scheduled messages (observed)

msg	kind	ctrl	tags	msgname	context
omnetpp::cMessage	0			broadcastTimer

Direct method calls (observed)

call to	function	info
MessageDispatcher	inet::MessageDispatcher::arrived	arrived
MessageDispatcher	inet::MessageDispatcher::handleRegisterProtocol	handleRegisterProtocol
MessageDispatcher	inet::MessageDispatcher::handleRegisterService	handleRegisterService
InterfaceTable	inet::InterfaceTable::findFirstNonLoopbackInterface	findFirstNonLoopbackInterface

Called methods (observed)

function	info	call from
inet::ProbabilisticBroadcast::handleRegisterProtocol	handleRegisterProtocol	MessageDispatcher
inet::ProbabilisticBroadcast::handleRegisterService	handleRegisterService	MessageDispatcher

Incoming messages (observed)

gate	msg	kind	ctrl	srcModule	tags
queueIn	Packet	0		EthernetEncapsulation	DispatchProtocolReq, InterfaceInd, MacAddressInd, PacketProtocolTag
transportIn	Packet	0		PingApp	DispatchProtocolReq, L3AddressReq, PacketProtocolTag, SocketReq
transportIn	Packet	0		EchoProtocol	DispatchProtocolReq, L3AddressReq, PacketProtocolTag
transportIn	Request	1	L3SocketBindCommand	PingApp	DispatchProtocolReq, SocketReq

Outgoing messages (observed)

gate	msg	destModule	tags
queueOut	Packet	EthernetEncapsulation	DispatchProtocolInd, DispatchProtocolReq, InterfaceReq, MacAddressReq, PacketProtocolTag, InterfaceInd?, L3AddressReq?, MacAddressInd?, SocketReq?
transportOut	Packet	PingApp	DispatchProtocolInd, DispatchProtocolReq, InterfaceInd, L3AddressInd, MacAddressInd, MacAddressReq, NetworkProtocolInd, PacketProtocolTag, SocketInd
transportOut	Packet	EchoProtocol	DispatchProtocolInd, DispatchProtocolReq, InterfaceInd, L3AddressInd, MacAddressInd, MacAddressReq, NetworkProtocolInd, PacketProtocolTag

Packet operations (observed)

chunkType	packetAction
	trim
ProbabilisticBroadcastHeader	insertAtFront, peekAtFront, popAtFront, removeAtFront

Shared Tagging operations (observed)

tagType	tagAction
DispatchProtocolInd	addTagIfAbsent
DispatchProtocolReq	addTagIfAbsent
InterfaceReq	addTagIfAbsent
L3AddressInd	addTagIfAbsent, getTag
MacAddressInd	getTag
MacAddressReq	addTagIfAbsent
NetworkProtocolInd	addTagIfAbsent
PacketProtocolTag	addTagIfAbsent, getTag
SocketInd	addTagIfAbsent
SocketReq	getTag

Tagging operations (observed)

tagType	tagAction
inet::Ipv4InterfaceData	findTag
inet::Ipv6InterfaceData	findTag
inet::NextHopInterfaceData	findTag

Source code

//
// Multi-hop ad-hoc data dissemination protocol based on probabilistic broadcast.
//
// This method reduces the number of packets sent on the channel (reducing the
// broadcast storm problem) at the risk of some nodes not receiving the data.
// It is particularly interesting for mobile networks.
// Parameter maxNbBcast sets the maximum number of broadcast transmissions of a packet,
// parameter beta gives the transmission probability for each attempt,
// parameter bcperiod sets the time between two transmission attempts.
// Parameter maxFirstBcastBackoff sets a backoff window before first transmission attempt,
// and parameter timeInQueueAfterDeath sets the time during which a node remembers
// a packet whose time to live (TTL) expired, avoiding retransmitting it in case it comes back
// in the network because of some problem.
//
simple ProbabilisticBroadcast extends NetworkProtocolBase like INetworkProtocol
{
    parameters:
        @class(ProbabilisticBroadcast);
        int headerLength @unit(b) = default(96b); // length of the network packet header (in bits)
        // period between two probabilistic broadcast attempts
        double bcperiod @unit(s) = default(2 s);
        // probability of broadcast for each attempt
        double beta = default(0.8);
        // maximal number of broadcast attempts for each packet.
        int maxNbBcast = default(1);
        // maximal back-off before first broadcast attempt [seconds].
        // if don't want to use this parameter, simply set it
        // to a value that is greater than bcperiod.
        double maxFirstBcastBackoff @unit(s) = default(1 s);

        double timeToLive @unit(s) = default(10 s);
        // How many seconds 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.
        double timeInQueueAfterDeath @unit(s) = default(60 s);
}

File: src/inet/networklayer/probabilistic/ProbabilisticBroadcast.ned