bcds.phison.multfailures
Class PmStatic<V,E>

java.lang.Object
  bcds.phison.sim.PmBase<V,E>
      bcds.phison.multfailures.PmStatic<V,E>

All Implemented Interfaces:

ProcessingModule<V,E>, WithEnvParams

public class PmStatic<V,E>
extends PmBase<V,E>

This module implements static failures, which are defined as one-off failures that affect one or more elements (nodes or links) at any given point. It receives six parameters:

• init_time: the time step in which the failure is provoked. It should be greater than 1. This parameter is mandatory because if no value is provided it throws an IllegalArgumentException Default: 0.
• i_size: initial size of affected elements. It must be entered following the format: "number" or "percentage%". Default: "1".
• sequencer: Name of the class to be used as sequencer, which must implement ElemsSequencer and which must support the specified target. Default: bcds.phison.multfailures.SequencerRandom.
• target: The type of elements to work with: one of node or link. If it is link, it is always considered the graph as undirected. Default: node.
• mttr_mu: The mean of the Log-normal distribution that represents the Mean Time to Repair (MTTR) of the network elements. It can be any double value. With the default value elements are considered to not have MTTR (once failed they never repair again). Default: Double.POSITIVE_INFINITY.
• mttr_sigma The standard deviation of the Log-normal distribution that represents the MTTR of the network elements. Default: 0.

The module affects i_size elements at time step init_time. Elements are selected according to the sequencer given by the user. Elements can be nodes or links, depending on target.

The MTTR represents the average time required to repair a failed element. According to [1] and other online materials, the MTTR is usually treated as a log-normal random variable. In order to assign a MTTR to each element of the network, this module uses RndLogNormal, which needs a mean (mttr_mu) and a standard deviation (mttr_sigma). In the example shown below, the 9 given to mttr_mu could be related with any time unit, for example, hours.

The output of the module are, as a consequence of the failure:

• The average path length of the removed connections.
• The path length frequency distribution of the removed connections.

Although this is a "processing module", it is intended to be used primarily alone. Thus, a typical way to invoke it through Sim from command-line is:

   (cat <<END
   PmStatic.target=node
   PmStatic.init_time=1
   PmStatic.i_size=3%
   PmStatic.sequencer=SequencerDegree
   PmStatic.mttr_mu=9
   PmStatic.mttr_sigma=0.5
   END
   ) | java -jar phison.jar Sim -env_file=- -stdm=false -q \
            -num_rep=10 rep_out=some_file_{%d}.out -maxtime=100 \
            -mp=bcds.phison.multfailures \
            -modules=PmStatic \
            mytopology.sgf
 

References:
[1] http://www.nasa.gov/offices/oce/llis/0840.html

Author:

mmanzano

Nested Class Summary

static class

PmStatic.States The possible states of each element.

Field Summary

java.lang.String	I_SIZE See getEnvParams().
java.lang.String	INIT_TIME See getEnvParams().
java.lang.String	MTTR_MU See getEnvParams().
java.lang.String	MTTR_SIGMA See getEnvParams().
java.lang.String	SEQUENCER See getEnvParams().
java.lang.String	TARGET See getEnvParams().

Constructor Summary

PmStatic()

Method Summary

void	actOnPaths(java.util.HashSet<E> links) Forcibly releases all connections that are affected by the the fact that a element went into the state NOK.
void	collectConnectionsStats() Collects the lost connections statistics for this module.
java.lang.Object[]	getEnvParams() Returns the list of environment parameters and default values of this class.
void	reinstallLinks(java.util.HashSet<E> links, int clock) Links that in the previous time steps were unavailable but are now back into operation, are reactivated by calling TED.reinstallBidiLinks(java.util.Collection, int).
void	retireLinks(java.util.HashSet<E> links) Makes sure that all links are unavailable for traffic in the future.
void	setup(SimCore<V,E> sim) Saves the parameter sim, which can later be obtained by calling the sim() method.

Methods inherited from class bcds.phison.sim.PmBase

ctx, env, getEnviron, getId, getName, opt, run, shutdown, sim, stats

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INIT_TIME

public final java.lang.String INIT_TIME

See getEnvParams().

I_SIZE

public final java.lang.String I_SIZE

See getEnvParams().

SEQUENCER

public final java.lang.String SEQUENCER

See getEnvParams().

TARGET

public final java.lang.String TARGET

See getEnvParams().

MTTR_MU

public final java.lang.String MTTR_MU

See getEnvParams().

MTTR_SIGMA

public final java.lang.String MTTR_SIGMA

See getEnvParams().

Constructor Detail

PmStatic

public PmStatic()

Method Detail

setup

public void setup(SimCore<V,E> sim)

Description copied from class: PmBase

Saves the parameter sim, which can later be obtained by calling the sim() method. It also calls adaptTypes if the environment object is non-null (which should normally be).

Specified by:

setup in interface ProcessingModule<V,E>

Overrides:

setup in class PmBase<V,E>

collectConnectionsStats

public void collectConnectionsStats()

Collects the lost connections statistics for this module.

retireLinks

public void retireLinks(java.util.HashSet<E> links)

Makes sure that all links are unavailable for traffic in the future. This is achieved by calling TED.retireBidiLinks(java.util.Collection).

reinstallLinks

public void reinstallLinks(java.util.HashSet<E> links,
                           int clock)

Links that in the previous time steps were unavailable but are now back into operation, are reactivated by calling TED.reinstallBidiLinks(java.util.Collection, int).

actOnPaths

public void actOnPaths(java.util.HashSet<E> links)

Forcibly releases all connections that are affected by the the fact that a element went into the state NOK.

getEnvParams

public java.lang.Object[] getEnvParams()

Returns the list of environment parameters and default values of this class. They are prefixed by "PmStatic and are:

• init_time: the time step in which the failure is provoked. It should be greater than 1. This parameter is mandatory because if no value is provided it throws an IllegalArgumentException Default: 0.
• i_size: initial size of affected elements. It must be entered following the format: "number" or "percentage%". Default: "1".
• sequencer: Name of the class to be used as sequencer, which must implement ElemsSequencer. Default: bcds.phison.multfailures.SequencerRandom.
• target: The type of elements to work with: one of node or link. Default: node.
• mttr_mu: The mean of the Log-normal distribution that represents the Mean Time to Repair (MTTR) of the network elements. It can be any double value. With the default value elements are considered to not have MTTR (once failed they never repair again). Default: Double.POSITIVE_INFINITY.
• mttr_sigma The standard deviation of the Log-normal distribution that represents the MTTR of the network elements. Default: 0.

Specified by:

getEnvParams in interface WithEnvParams

Overrides:

getEnvParams in class PmBase<V,E>