HELP FROM THE SKY: LEVERAGING UAVS FOR DISASTER MANAGEMENT

Sedef SavasFebruary17th, 2016

Netlab Friday Group Meeting

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ControlPlane MappingProblem

Designaresilientcontrolplanethatsatisfylatencyconstraints.

Adistributedcontrolplanecanbedesignedasanoverlay(i.e.,virtual/logical)networkmappedoveraphysical(i.e.,backbone)network.• virtualnodeswherecontrollersarelocatedandvirtuallinksconnects

them.

We propose a survivable control plane mapping scheme to ensure control-planeconnectivity against both single point of failures and large-scale disaster failures inSDN.

ProblemformulationGiven:Topology,Datacenterlocations,Disastersize

ObjectiveFindminimum#ofcontrollers,placethem,connectthem,assignswitchestothem.

ConstraintsLatencyrequirements:Limitsworstcase.

1. Maximumlatencybetweenswitchesandcontrollers.2. Maximumlatencybetweenanycontrollerpair,affects

synchronizationtime.3. Maximumpathsetuplatency.

Switchcontrollerlatency’saffect:Forallpossibledisasters,afterfailure,makesurethereisapathtoacontrollerwithinlatencylimits.Thiswillbepreprocessed.

DataPlane

C1

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ControlPlaneC1 C2

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Synchronization latency

Periodically,flooding stateupdates.Noteverycontrollersendseveryothercontrollerthesameinfo.

DataPlane

C1

C2

ControlPlaneC1 C2

C3

C3

Worst case path setup latency

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Controllers: close to switches or other controllers?

Switch-controller communication:Periodic state updateNew flow setup

Controller-controller communication:SynchronizationNew rule installation requests

Dependsonthetopologyandconstraints:Manyswitchesconnecttoasinglecontroller:Controllersshouldbeclosertoswitches inmanyswitcheswithhighloadsscenario.Moreflowsdonotneedtobesenttoothercontrollers,butroutedwithinthecluster.Decreaseflowsetuplatency.

Ifnotmuchcanbegainedfromplacingcontrollersapart,thenplacethemclose.Decreasesynchronization.

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Close to other controllers

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Close to other controllers

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SamepathsetupdelayLongersynchronization latencyLesss-cbw consumption /morec-c(negligible)Lessresourceusage????

Close to switches

Maxlatencybetweenrouter-controller(30% ofthegraphdiameter)andcontroller-controller(70%ofthegraphdiameter)isset.

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Constraints(cont.)CapacityrequirementsDatacentershavecapacitylimit.Eachcontrollerwillberesponsibleofalimited#ofnodes.

Resiliency/Connectivityrequirement:• Controlplaneresilientagainstsinglepointoffailures.Atleast2-connected.Depending

onthedisasterrangeandthetopologymoremaybeneeded.

• Afteranydisasteratsizer,alivecontrollersstayconnected.Andallswitchescanbeassignedtoaswitchwithin latencyconstraint.

• Initially,atleast2controllerswithin latencyrequirementofswitchestoachievethese.

Assumptions

• Uniformdemand.• Onlyspecificnodescanbecontrollerlocations.• Eachroutertoexactlyonecontroller.• Allswitchesbeingcontrolledbytheirnearestcontrollerandallcontrolpathsbeingthe

shortestpathsbetweentheswitchandtheassignedcontroller.

• Donotconsiderbackupsbetweenswitchesandcontrollers.Aslongascontrolplaneisupandphysicallayerisconnected,controlplanewillreachunattachedswitches.Hardtofinddisjointpathsthatwillsurviveallr-sizeddisasters.

Donotconsiderreassignmentsincaseofdisasters,onedisasteratatime,noneedtoconsidernormalmodeofop.constraints(onlylatency),sonotmuchtoshow.Designproblem.

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Modeling disasters

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AlgorithmMany components of the problem is NP-Hard.• CPP reduces to a Facility Location Problem and is proved to be NP Hard.• VNE is NP-Hard.

Decomposition technique based heuristic algorithm: to reduce the computational complexity The main idea of our algorithms is to decompose the primal problem into |R| sub-problems and solve these sub-problems separately.

For VNE: this means, the mapping for virtual nodes and links are completed in ordered phases.

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1. Foreachnode,findthesetofnodeswithinreachabilitycircle.

2. FindlistofminimumnodesthatmustexistintheVN,consideringeachswitchneed2closebycontrollers,consideringcapacityrequirements.Minimalsetcover.Sortthose listacc.tonumbernodesthatmustbeintheVN.

3. Here,wehavelistofnodesthatsatisfyinitiallatencyrequirementandthecapacityrequirement.Switchassignmentisalsodoneatthisstageforalloptions.

4. Amongthose lists,calculateworstcasepathsetup.Findfarmost nodepair.Calculateworstcasepathsetup.Wehaveswitchassignments.ShortestpathsNodeA tocontA +nodeB tocont b+contbtocont a->areconsideredworstcase.Eliminateliststhatdonotmeetworstcasepathsetuprequirement.Sorttherest.

5. During the eliminations if no lists meet requirements, add more nodes in prev. steps.

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From now on, consider disaster resilience.

Sort the remaining lists acc. to maximum damage done based on the affected number of elements/connections (s-c shortest paths + controllers + c-c connections(connect all controllers to the closest controller to them with shortest path)) by a certain-sized disaster.

Up until now, we decide on the number of nodes, their locations, switch assignments.

Deciding on VN links and mappings: 2-connected. Ensure connectivity in case of any disaster sized r. Control plane latency requirement for a full synchronization.

Minimize # of controllers by increasing controller number only when it is needed.Not every distribution of dcs or amount gives feasible solutions. Only consider the ones that do give.

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UMREQUIREDCONTROLLER

MAXS-CLATENCY(%)

S-Clatency+Disaster resiliency

(AllDCnodes.C-C100%)

disasterr=100km

MaxS-Cdelay%100%(5000km) 80%(4000) 60%(3000) 40%(2000) 20%(1000)

100 80 60 40 20#DC 2 3 4 8 unfeasibleDC

percentage 0.0833 0.125 0.1666 0.3333 unfeasible

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Sensitivity analysis• EffectofDClocationsandamount.

• Theeffectof topology? #ofnodes,averagelinklengths,andconnectivityproperties. Iflinksarelonger,morecontrollersneededwhenthedelaytoleranceissame.

• Theeffectdelaytolerance?

• Theeffectof thesizeofthedisaster?

• Theeffectofcontrollercapacity?

TheInternationalSearchandRescueAdvisoryGroup(INSARAG)

INSARAGisaglobalnetworkof80countriesandorganizationsundertheUnitedNationsumbrella.

Purpose:Strengtheningtheeffectivenessandcoordinationofinternationalurbansearchandrescueassistance

INSARAG

• INSARAG’sinternationalSARprotocolSARprocessmustbeconductedbyteams.• Activityassignmentandlocaldecisionsarebroughtbyateamleader,whilealltheteam

activitiesarecoordinatedbyanincidentcommander.AcommonSARmissionisconductedinfourmajorsteps:

• 1)thecommanderestablishesthesearcharea(asmallersearchareaminimizetheproblemsofcommunicationamongtherescuers),

• 2)establishingofacommandpostinthesearcharea,• 3)firstrespondersaredividedintoscoutsandrescuers,• 4)scoutteamsreport theirfindingstothecommandpostandrescuersgather the

information

HelpfromtheSky:LeveragingUAVsforDisasterManagement(1)

Leveragingthelatestadvancesinwirelesssensornetwork(WSN)andUAVstoenhancetheabilityofnetwork-assisteddisasterprediction,assessment,andresponse.

geophysical (earthquake,tsunami,volcano,landslide,andavalanche),hydrological (flash-foods,debrisflow,andfloods),climatological (extremetemperature,drought,andwildfire)meteorological (tropicalstorm,hurricane,sandstorm,andheavyrain- fall)

Erdelj,Milan,EnricoNatalizio,KaushikR.Chowdhury, andIanF.Akyildiz."HelpfromtheSky: LeveragingUAVsforDisasterManagement." IEEEPervasiveComputing 16,no.1(2017):24-32.

HelpfromtheSky:LeveragingUAVsforDisasterManagement(2)

Themajorproblemisthelackofcommunicationandsituationalawarenessduringadisaster,forcingfirstresponderteamstoimproviseandthusdegradingtheefficiencyoftherescuemission.

First72hours,afterthedisasterhitarethemostcritical,whichmeansthatSearchandRescue(SAR)operationsmustbeconductedquicklyandefficiently.

Erdelj,Milan,EnricoNatalizio,KaushikR.Chowdhury, andIanF.Akyildiz."HelpfromtheSky: LeveragingUAVsforDisasterManagement." IEEEPervasiveComputing 16,no.1(2017):24-32.

HelpfromtheSky:LeveragingUAVsforDisasterManagement(3)Energy-effectivenesstradeoffs.Currentlyavailableoff-the-shelfUAVscanremainairborneforapproximately15–20minutesatatime.Thus,theirmissionmustbehighlyoptimized.Dynamictopologies.Theoreticaloraprioriplacementoptimizationsdonecentrallymightnottranslatetothesameexactlocationsinthecorresponding3Dairspace.Unpredictableairdrafts,inaccuraciesinthe3Dchannelmod- els,andon- eld changingconditionscanrequiresuddenandunanticipatedchangesinUAVlocalization.Protocolsthatrelyonnext-hopforwarding,link- layerretransmissions,anderrorcon- trol,amongotherapproaches,mustadjusttothesesituations inrealtime.Multi-objectivedowntimes.Giventheen- ergy demands,UAVsengagedinSARfunctionsrequiremultipleroundsofre- charging.EachsuchdowntimerecallstheUAVtothenearestchargingcenter,whichraisesinterestingquestions regard- ing whetherthesamenetworkcanbemaintained(byintroducingredundancy)ortheentiretopologymustbeproactivelychanged(atthecostofperformance).

Erdelj,Milan,EnricoNatalizio,KaushikR.Chowdhury, andIanF.Akyildiz."HelpfromtheSky: LeveragingUAVsforDisasterManagement." IEEEPervasiveComputing 16,no.1(2017):24-32.

20-30minutesairborneoperationduration,80minuteschargingduration.

Afixedormobilefirst-responseUAVstation• automaticbatteryreplacement

Single optimized but static network for all three stages is no longer sustainable; rather, the network must continuously evolve in topology and capability.

SincetheWSNisstilloperationalandabletoroutepacketstotheremotesink,themobileunitsperformmoreoftheexploratorytasksbutthenleveragethelong-livedWSNasthedata-forwardingbackhaul(bufferanddistributepacketsalongtheend-to-endchain).

Challenges

Supportingin-networkdatafusion.Thevideo/imagescollectedbytheUAVspresentanoverviewofthesituation.AffectedhumansmightmediaviatheUAVrelaynetworkalsouseful.

Addressinghandoverissues.Unlikehandoff incellularsystems,thehand- overamongUAVs—suchasduringrechargingevents—isconsiderablymoreinvolved.AhandoverinvolvesreplicatingtheexactoperationalstateintheincomingUAV—includingforwardingtables,packets inthebuffer,anddatafusionrules—whichescalatesthemessagingbetweentheUAVs.

Systemsandmethodsforamobileuav-basedemergencycommunicationscanner (16PatentbyNokia)MotivationInprev.works,UAVsareconsideredasanetworkelementandtoreplacethedamagedinfrastructures.ThisrequiresaUAVtohoveroveralocationcontinuously.Benefit:real-timecommunication

UAVwouldonlyactasa“Post-man”whereintheUAVswouldcollectthesignals(eg.,SMS),gotoanearbytoweranddeliverthesignalsorvice-versaBenefits:cost-effective

Systemsandmethodsforamobileuav-basedemergencycommunicationscanner (16PatentbyNokia)UAVbasedemergencycommunicationscanneriscomprisedofanunmannedaerialvehicle(UAV),deployedsensorresources,mappingapplicationandabig-datacenter.

• Dataiscollectedindistributedmanner• UseslocalizedcollectionofdatabyUAV'stoavoidhigh-burstcommunicationscenarios• InabsenceofUAV's,systemcanprovideofflinedatacollectioncapabilitiestominimizestress

onthenetwork.• UAV'sresolvedatacollectionproblemwhenconventionalcommunicationchannelsarenot

available• Abletocollectvisualdatafromdatacollectionareas.• Longerbatterylife

CreatingNetworkResilienceAgainstDisastersUsingServiceLevelAgreementsNetworkhasdifferentdemandsandrequirementswhenitisnormalthanwhenitisinadisasteroremergencystatus.

ifresourcesareIimited followingthedisaster,howdoweselectwhichservicestoreroute?Ontheprovisioningside,theSLAswillprovidetherequiredsystemresponsetime,availabilityandsurvivabilityofaservice.Ontheremediationside,theSLAcanprovidethepriorityofaservicetorestoreandreroute.

Gardner, M.T.,Cheng,Y.,May,R.,Beard, C.,Sterbenz,J.,&Medhi,D.(2016,March).Creating networkresilience againstdisastersusingservicelevelagreements.InDesignofReliableCommunication Networks(DRCN), 201612thInternational Conferenceonthe (pp.62-70).IEEE.

CreatingNetworkResilienceAgainstDisastersUsingServiceLevelAgreementsNetworkhasdifferentdemandsandrequirementswhenitisnormalthanwhenitisinadisasteroremergencystatus.

ifresourcesareIimited followingthedisaster,howdoweselectwhichservicestoreroute?Ontheprovisioningside,theSLAswillprovidetherequiredsystemresponsetime,availabilityandsurvivabilityofaservice.Ontheremediationside,theSLAcanprovidethepriorityofaservicetorestoreandreroute.

Gardner, M.T.,Cheng,Y.,May,R.,Beard, C.,Sterbenz,J.,&Medhi,D.(2016,March).Creating networkresilience againstdisastersusingservicelevelagreements.InDesignofReliableCommunication Networks(DRCN), 201612thInternational Conferenceonthe (pp.62-70).IEEE.

ResilientSLAConfigurationResponseTimeisthemaximumend-to-endresponsetimeAvailability isusedtospecifytheserviceavailability.ISurvivability isspecifiedfortheemergencydemandsdthatarerequiredduringtimesofnetworkchallenge.Ifaservicewithsurvivabilityisspecifiedbutisnotofhighavailability,itmaynotberestoredduringanormalcomponentfailurebutwouldbereroutedwithpriorityduringnetworkchallenges.

Reroutetheemergencyoperatingmodeservicesfirst,andthenreroutetheremainingservicesusingshortestpathrouting.

Gardner, M.T.,Cheng,Y.,May,R.,Beard, C.,Sterbenz,J.,&Medhi,D.(2016,March).Creating networkresilience againstdisastersusingservicelevelagreements.InDesignofReliableCommunication Networks(DRCN), 201612thInternational Conferenceonthe (pp.62-70).IEEE.