Simple Module ProbabilisticBroadcast

Package: org.mixim.modules.netw
File: modules/netw/ProbabilisticBroadcast.ned

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

This protocol performs network-level broadcast using a probabilistic mechanism. 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.

Usage diagram:

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Inheritance diagram:

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Extends:

BaseNetwLayer (simple module)

Base module for every network layer module

Known subclasses:

AdaptiveProbabilisticBroadcast (simple module)

Multi-hop ad-hoc data dissemination protocol based on probabilistic broadcast, with adaptive parameters.

Parameters:

Name	Type	Default value	Description
notAffectedByHostState	bool	false
coreDebug	bool		debug switch for core framework
stats	bool		stats switch
headerLength	double		length of the network packet header (in bits)
debug	bool	false	debug and trace switches
trace	bool	false
bcperiod	double	2 s	period between two probabilistic broadcast attempts
beta	double	0.8	probability of broadcast for each attempt
maxNbBcast	double	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
class	ProbabilisticBroadcast

Gates:

Name	Direction	Description
upperGateIn	input	from upper layer
upperGateOut	output	to uppe layer
upperControlIn	input	control from upper layer
upperControlOut	output	control to upper layer
lowerGateIn	input	from lower layer
lowerGateOut	output	to lower layer
lowerControlIn	input	control from lower layer
lowerControlOut	output	control to lower layer

Source code:

// Multi-hop ad-hoc data dissemination protocol based on probabilistic broadcast.
//
// This protocol performs network-level broadcast using a probabilistic mechanism.
// 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 BaseNetwLayer
{
    parameters:
        @class(ProbabilisticBroadcast);
        // debug and trace switches
        bool debug = default(false);
        bool trace = default(false);
        // 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.
        double 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);

}