com.net2plan.libraries

Class SRGUtils

java.lang.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.

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

Modifier and Type	Method and Description
static DoubleMatrix1D	computeStateProbabilities(DoubleMatrix2D A_sf, DoubleMatrix1D 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, NetworkLayer... optionalLayerParameter) Configures the SRGs into the network design at the given layer.
static List<SortedSet<SharedRiskGroup>>	enumerateFailureStates(Collection<SharedRiskGroup> srgs, boolean considerNoFailureState, boolean considerDoubleFailureStates) Returns the set of SRGs going down on each failure state.
static SortedSet<SharedRiskGroup>	getAffectingSRGs(Collection<Link> links) Returns a set of SRGs that are affecting the given links.
static DoubleMatrix2D	getMatrixFailureState2SRG(Collection<SharedRiskGroup> srgs, boolean considerNoFailureState, boolean considerDoubleFailureStates) Returns a matrix indicating the SRGs going down (columns) on each failure state (rows).
static DoubleMatrix2D	getMatrixFailureStates2SRG(Collection<SharedRiskGroup> srgs, boolean considerNoFailureState, boolean considerDoubleFailureStates) Returns a matrix indicating the SRGs going down (columns) on each failure state (rows).
static Pair<Double,Double>	getSRGDisjointnessPercentage(NetPlan netPlan, NetworkLayer... optionalLayerParameter) Returns the percentage of SRG disjointness of traffic routes and their backup paths defined.
static String	getSRGModel(NetPlan netPlan, NetworkLayer... optionalLayerParameter) 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 boolean	isSingleSRGFailureTolerant(NetPlan np, NetworkLayer failureTolerantLayer) Returns true if the given design is tolerant to single SRG failures at the given layer: that is, no traffic of any unicast not multicast demand is blocked when such SRG fails
static boolean	isSRGDisjoint(Collection<Link> path1, Collection<Link> path2) Returns true if the two collection of links in path1 and paths (not necessarily a sequence of contiguous links forming a path), are srg disjoint

Methods inherited from class java.lang.Object

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

Method Detail

computeStateProbabilities

public static DoubleMatrix1D computeStateProbabilities(DoubleMatrix2D A_sf,
                                                       DoubleMatrix1D A_f)

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

Parameters:

A_sf - SRGs failing (columns) per each failure state (rows)

A_f - Availability value per SRG

Returns:

Probability to find the network in each failure state

configureSRGs

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

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

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 - Wheter or not to remove existing SRGs

optionalLayerParameter - Network layer (optional)

enumerateFailureStates

public static List<SortedSet<SharedRiskGroup>> enumerateFailureStates(Collection<SharedRiskGroup> srgs,
                                                                      boolean considerNoFailureState,
                                                                      boolean considerDoubleFailureStates)

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

Parameters:

srgs - SRGs

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:

List of SRGs going down on each failure state

getAffectingSRGs

public static SortedSet<SharedRiskGroup> getAffectingSRGs(Collection<Link> links)

Returns a set of SRGs that are affecting the given links.

Parameters:

links - Collection of links

Returns:

SRGs affecting the links

getMatrixFailureState2SRG

public static DoubleMatrix2D getMatrixFailureState2SRG(Collection<SharedRiskGroup> srgs,
                                                       boolean considerNoFailureState,
                                                       boolean considerDoubleFailureStates)

Returns a matrix indicating the SRGs going down (columns) on each failure state (rows).

Parameters:

srgs - SRGs

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:

Matrix of SRGs going down on each failure state

getMatrixFailureStates2SRG

public static DoubleMatrix2D getMatrixFailureStates2SRG(Collection<SharedRiskGroup> srgs,
                                                        boolean considerNoFailureState,
                                                        boolean considerDoubleFailureStates)

Returns a matrix indicating the SRGs going down (columns) on each failure state (rows).

Parameters:

srgs - SRGs

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:

Matrix of SRGs going down on each failure state

getSRGDisjointnessPercentage

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

Returns the percentage of SRG disjointness of traffic routes and their backup paths defined.

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

Parameters:

netPlan - Current network design

optionalLayerParameter - Network layer (optional)

Returns:

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

getSRGModel

public static String getSRGModel(NetPlan netPlan,
                                 NetworkLayer... optionalLayerParameter)

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

optionalLayerParameter - Network layer (optional)

Returns:

Description of the current SRG model

isSingleSRGFailureTolerant

public static boolean isSingleSRGFailureTolerant(NetPlan np,
                                                 NetworkLayer failureTolerantLayer)

Returns true if the given design is tolerant to single SRG failures at the given layer: that is, no traffic of any unicast not multicast demand is blocked when such SRG fails

Parameters:

np - the design

failureTolerantLayer - the layer where we check tolerance

Returns:

see above

isSRGDisjoint

public static boolean isSRGDisjoint(Collection<Link> path1,
                                    Collection<Link> path2)

Returns true if the two collection of links in path1 and paths (not necessarily a sequence of contiguous links forming a path), are srg disjoint

Parameters:

path1 - the first collection of links

path2 - the second collection of links

Returns:

see above