com.net2plan.libraries

Class SRGUtils

Object

com.net2plan.libraries.SRGUtils

public class SRGUtils
extends Object

Provides a set of static methods which can be useful when dealing with network resilience.

Since:

0.2.3

Author:

Pablo Pavon-Marino, Jose-Luis Izquierdo-Zaragoza

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SRGUtils.SharedRiskModel Type of shared-risk model.

Method Summary

Methods

Modifier and Type	Method and Description
static cern.colt.matrix.tdouble.DoubleMatrix2D	computeFailureState2LinkUnavailabilityMatrix(NetPlan netPlan, List<Set<Long>> F_s) Given a network design with a set of shared-risk groups (SRGs) and a set of failure states, each of them containing the associated set of simultaneous SRG failures, the failure state-link unavailability matrix.
static cern.colt.matrix.tdouble.DoubleMatrix2D	computeFailureState2LinkUnavailabilityMatrix(NetPlan netPlan, long layerId, List<Set<Long>> F_s) Given a network design with a set of shared-risk groups (SRGs) and a set of failure states, each of them containing the associated set of simultaneous SRG failures, the failure state-link unavailability matrix.
static cern.colt.matrix.tdouble.DoubleMatrix2D	computeSRG2LinkUnavailabilityMatrix(NetPlan netPlan) Given a network design with a set of shared-risk groups (SRGs), it computes the SRG-link unavailability matrix.
static cern.colt.matrix.tdouble.DoubleMatrix2D	computeSRG2LinkUnavailabilityMatrix(NetPlan netPlan, long layerId) Given a network design with a set of shared-risk groups (SRGs), it computes the SRG-link unavailability matrix.
static List<Double>	computeStateProbabilities(List<Set<Long>> F_s, Map<Long,Double> A_f) Computes the probability to find the network on each failure state.
static void	configureSRGs(NetPlan netPlan, double defaultMTTF, double defaultMTTR, SRGUtils.SharedRiskModel sharedRiskModel, boolean removeExistingSRGs) Configures the SRGs into the network design at the first layer.
static void	configureSRGs(NetPlan netPlan, long layerId, double defaultMTTF, double defaultMTTR, SRGUtils.SharedRiskModel sharedRiskModel, boolean removeExistingSRGs) Configures the SRGs into the network design at the given layer.
static List<Set<Long>>	enumerateFailureStates(Set<Long> srgIds, boolean considerNoFailureState, boolean considerDoubleFailureStates) Returns the set of SRGs going down on each failure state.
static Pair<Double,Double>	getSRGDisjointnessPercentage(NetPlan netPlan) Returns the percentage of SRG disjointness of traffic routes and protection segments.
static Pair<Double,Double>	getSRGDisjointnessPercentage(NetPlan netPlan, long layerId) Returns the percentage of SRG disjointness of traffic routes and protection segments.
static String	getSRGModel(NetPlan netPlan) Indicates whether SRG definition follows one of the predefined models (per node, per link...), or 'Mixed' otherwise (or 'None' if no SRGs are defined).
static String	getSRGModel(NetPlan netPlan, long layerId) Indicates whether SRG definition follows one of the predefined models (per node, per link...), or 'Mixed' otherwise (or 'None' if no SRGs are defined).

Methods inherited from class Object

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

Method Detail

computeFailureState2LinkUnavailabilityMatrix

public static cern.colt.matrix.tdouble.DoubleMatrix2D computeFailureState2LinkUnavailabilityMatrix(NetPlan netPlan,
                                                                                   List<Set<Long>> F_s)

Given a network design with a set of shared-risk groups (SRGs) and a set of failure states, each of them containing the associated set of simultaneous SRG failures, the failure state-link unavailability matrix. This is a matrix with as many rows as failure states, and as many columns as links. Position (f, e) has a 1 if link e (e = 0 refers to the first link in linkMap.keySet(), e = 1 refers to the second one, and so on) is affected by failure state f (f = 0 refers failure state, f = 1 refers to the second one, and so on), considering either the link itself or some of the end nodes.

This method is an extended version of computeSRG2LinkUnavailabilityMatrix, since it allows to consider not only single SRG failures, but also simultaneous SRG failures.

Parameters:

netPlan - Network design containing a set of shared-risk groups

F_s - List of failure states, each of them containing the associated set of simultaneous SRG failures

Returns:

Failure state-link unavailability matrix

Since:

0.3.1

computeFailureState2LinkUnavailabilityMatrix

public static cern.colt.matrix.tdouble.DoubleMatrix2D computeFailureState2LinkUnavailabilityMatrix(NetPlan netPlan,
                                                                                   long layerId,
                                                                                   List<Set<Long>> F_s)

Given a network design with a set of shared-risk groups (SRGs) and a set of failure states, each of them containing the associated set of simultaneous SRG failures, the failure state-link unavailability matrix. This is a matrix with as many rows as failure states, and as many columns as links. Position (f, e) has a 1 if link e (e = 0 refers to the first link in linkMap.keySet(), e = 1 refers to the second one, and so on) is affected by failure state f (f = 0 refers failure state, f = 1 refers to the second one, and so on), considering either the link itself or some of the end nodes.

This method is an extended version of computeSRG2LinkUnavailabilityMatrix, since it allows to consider not only single SRG failures, but also simultaneous SRG failures.

Parameters:

netPlan - Network design containing a set of shared-risk groups

layerId - Layer identifier

F_s - List of failure states, each of them containing the associated set of simultaneous SRG failures

Returns:

Failure state-link unavailability matrix

Since:

0.3.1

computeSRG2LinkUnavailabilityMatrix

public static cern.colt.matrix.tdouble.DoubleMatrix2D computeSRG2LinkUnavailabilityMatrix(NetPlan netPlan)

Given a network design with a set of shared-risk groups (SRGs), it computes the SRG-link unavailability matrix. This is a matrix with as many rows as SRGs, and as many columns as links. Position (s, e) has a 1 if link e (e = 0 refers to the first link in linkMap.keySet(), e = 1 refers to the second one, and so on) is affected by the failure of SRG s (s = 0 refers to the first defined SRG, s = 1 refers to the second one, and so on), considering either the link itself or some of the end nodes.

Parameters:

netPlan - Network design containing a set of shared-risk groups

Returns:

SRG-link unavailability matrix

Since:

0.3.1

computeSRG2LinkUnavailabilityMatrix

public static cern.colt.matrix.tdouble.DoubleMatrix2D computeSRG2LinkUnavailabilityMatrix(NetPlan netPlan,
                                                                          long layerId)

Given a network design with a set of shared-risk groups (SRGs), it computes the SRG-link unavailability matrix. This is a matrix with as many rows as SRGs, and as many columns as links. Position (s, e) has a 1 if link e (e = 0 refers to the first link in linkMap.keySet(), e = 1 refers to the second one, and so on) is affected by the failure of SRG s (s = 0 refers to the first defined SRG, s = 1 refers to the second one, and so on), considering either the link itself or some of the end nodes.

Parameters:

netPlan - Network design containing a set of shared-risk groups

layerId - Layer identifier

Returns:

SRG-link unavailability matrix

Since:

0.3.1

computeStateProbabilities

public static List<Double> computeStateProbabilities(List<Set<Long>> F_s,
                                     Map<Long,Double> A_f)

Computes the probability to find the network on each failure state.

Parameters:

F_s - Set of SRGs failing per each failure state

A_f - Availability value per SRG

Returns:

Probability to find the network in each failure state

Since:

0.3.0

configureSRGs

public static void configureSRGs(NetPlan netPlan,
                 double defaultMTTF,
                 double defaultMTTR,
                 SRGUtils.SharedRiskModel sharedRiskModel,
                 boolean removeExistingSRGs)

Configures the SRGs into the network design at the first layer. Existing SRGs will be removed.

Parameters:

netPlan - A network design containing a physical topology

defaultMTTF - Default value for mean time to fail (in hours). Zero or negative value means Double.MAX_VALUE

defaultMTTR - Default value for mean time to repair (in hours). Zero or negative value are not allowed

sharedRiskModel - Model defining SRGs

removeExistingSRGs - Indicates whether or not existing SRGs should be removed

Since:

0.2.3

configureSRGs

public static void configureSRGs(NetPlan netPlan,
                 long layerId,
                 double defaultMTTF,
                 double defaultMTTR,
                 SRGUtils.SharedRiskModel sharedRiskModel,
                 boolean removeExistingSRGs)

Configures the SRGs into the network design at the given layer. Existing SRGs will be removed.

Parameters:

netPlan - A network design containing a physical topology

layerId - Layer identifier

defaultMTTF - Default value for mean time to fail (in hours). Zero or negative value means Double.MAX_VALUE

defaultMTTR - Default value for mean time to repair (in hours). Zero or negative value are not allowed

sharedRiskModel - Model defining SRGs

removeExistingSRGs - Indicates whether or not existing SRGs should be removed

Since:

0.3.0

enumerateFailureStates

public static List<Set<Long>> enumerateFailureStates(Set<Long> srgIds,
                                     boolean considerNoFailureState,
                                     boolean considerDoubleFailureStates)

Returns the set of SRGs going down on each failure state.

Parameters:

srgIds - SRG identifiers

considerNoFailureState - Flag to indicate whether or not no failure state is included

considerDoubleFailureStates - Flag to indicate whether or not double failure states are included

Returns:

Set of SRGs going down on each failure state

Since:

0.2.3

getSRGDisjointnessPercentage

public static Pair<Double,Double> getSRGDisjointnessPercentage(NetPlan netPlan)

Returns the percentage of SRG disjointness of traffic routes and protection segments.

Parameters:

netPlan - Current network design

Returns:

Two SRG disjointness values (either considering or not end nodes) for the default layer of the netPlan object

Since:

0.2.3

getSRGDisjointnessPercentage

public static Pair<Double,Double> getSRGDisjointnessPercentage(NetPlan netPlan,
                                               long layerId)

Returns the percentage of SRG disjointness of traffic routes and protection segments.

Important: In case there are no SRGs, then it will return zero.

Parameters:

netPlan - Current network design

layerId - Layer identifier

Returns:

Two SRG disjointness values (either considering or not end nodes)

Since:

0.2.3

getSRGModel

public static String getSRGModel(NetPlan netPlan)

Indicates whether SRG definition follows one of the predefined models (per node, per link...), or 'Mixed' otherwise (or 'None' if no SRGs are defined).

Parameters:

netPlan - Current network design

Returns:

Description of the current SRG model in the default layer of the netPlan object

Since:

0.2.3

getSRGModel

public static String getSRGModel(NetPlan netPlan,
                 long layerId)

Indicates whether SRG definition follows one of the predefined models (per node, per link...), or 'Mixed' otherwise (or 'None' if no SRGs are defined).

Parameters:

netPlan - Current network design

layerId - Layer identifier

Returns:

Description of the current SRG model

Since:

0.3.0