Page 1
High-Al(tudeElectromagne(cPulse(HEMP)andSatelliteNetworks
December4th,2015
PI:BiswanathMukherjeeDis$nguishedProfessor
Preparedby:RafaelLourençoPhDStudent
DepartmentofComputerScienceUniversityofCalifornia,Davis
Comba3ngWMDA9acksinMul3-LayerMeshNetworks:FromAnaly3calStudiestoPrototype
ACK:DefenseThreatReduc3onAgency(DTRA)GrantNo:HDTRA1-14-1-0047(6.2,FundamentalResearch)
Page 2
Outline
• EMPBasicsandWeapons• NuclearHEMPProper3esandEffects• SatelliteNetworksBasics• HEMP’sImpactonSatellites• ProposedResearch:Post-HEMPRestora3onwithSatelliteAssistance
Page 3
EMPWeaponTypes
• NuclearHigh-Al(tudeElectromagne(cPulse(HEMP):Nucleardetona3onathighal3tudeprovokesComptonSca9eringwhichcombinedwithEarthMagne3cFieldgeneratescoherentpulse[1];
• High-PowerMicrowaves(HPM):High-frequencypulsefromnon-nucleardevice.Mightdestroyelectricalequipment.Suitcase-sizeddevicecoulddisruptequipmentamileaway[2];
• Electromagne(cBombs:Explosivesdestroyspecialelectriccircuit;
§ ExplosivelyPumpedCoaxialFluxCompressionGenerator(FCG):Oldeste-bomb,lowfrequencies(<1MHz),mostmicroelectronicsinvulnerable;
§ VirtualCathodeOscillator(VirCatOr):Morecomplex,provideshigherfrequencies.
ComptonSca+ering:Gammarays+air=>high-energyfreeelectronsat0.9Cspeed.
[1]Miller,ColinR."Electromagne3cpulsethreatsin2010."(2005)[2]Wilson,Clay."High-al3tudeelectromagne3cpulse(HEMP)andhighpowermicrowave(HPM)devices:Threatassessments."(2008)
Page 4
EMPWeapons’Proper3es
Weapon[1]
ProbabilityofUse[1]
LethalRange[1] VulnerableTargets[1] Poten(alAVackers[1] Shape[2]
NuclearHEMP Moderate
Upto1,500mileradius(Texassizedamagesaremoreprobable)
Electronics,computerchips,sensors,communica3ons,vehicles,powertransmissionsystems,civilianinfrastructure
Nuclearpowerswithballis3cmissiletechnology,RoguestatesHPMLowSeenoteIntegratedcircuits,circuitcards,relayswitchesUS,UK,Australia,Russia,Sweden
Semiisotropic,roundedU-shaped"smile"
FCG High 175meters
Unprotectedsystemsconnectedtolong-runwireslongerthan250feet,possiblypeople
ModernmilitariesDependentoncoil/structure,non-isotropic
VirCatOr Moderate 150meters
Integratedcircuits,circuitcards,relayswitch,possiblypeople
Anyinforma3onageadversaryDependentoncoil/structure,non-isotropic
CurrentHPMsystemsdon’tgenerateenoughpowertoguaranteedestruc3onofintegratedcircuitsonalargescale.
Dependentonantenna
[1]Miller,ColinR."Electromagne3cpulsethreatsin2010."(2005)[2]Wilson,Clay."High-al3tudeelectromagne3cpulse(HEMP)andhighpowermicrowave(HPM)devices:Threatassessments."(2008)
Page 5
NuclearHEMPProper3es
"Inthepast,thethreatofmutuallyassureddestruc;onprovidedalas;ngdeterrentagainsttheexchangeofmul;plehigh-yieldnuclear
warheads.However,nowevenasingle,low-yieldnuclearexplosionhighabovetheUnitedStates,oroveraba+lefield,canproducealarge-scaleEMPeffectthatcouldresultinawidespreadlossofelectronics,butnodirectfatali;es,andmaynotnecessarilyevokealargenuclearretaliatorystrike
bytheU.S.military."[2]
[2]Wilson,Clay."High-al3tudeelectromagne3cpulse(HEMP)andhighpowermicrowave(HPM)devices:Threatassessments."(2008)
Page 6
NuclearHEMPProper3es
Al3tudes>30km(22g/cm3air),line-of-sight,toofasttoharmhumans,composedofcumula3veconsecu3vepulses[4]:§ E1:nanoseconds,coherent,inducesextremelyhighvoltages
burningelectro/electronics,toofastforsurgeprotectors:Ø Mid-stratosphereioniza3onconvertregionintoelectrical
conductor;Ø 1.44MTat0.1%gammaefficiency=>2MeVgammarays
=>Peaking50MV/matfloorlevel;Ø 10kTbombsmightget40%efficiency[4];
§ E2:microsecondstoseconds,lessthan1saperE1,similartolightning;
§ E3(SolarEMP):temporarydistor3onofGeomagne3cfield,laststenstohundredsofseconds,similartoGeomagne3cStorm,inducecurrentsinlongconductors(powerlines).
Downward;ltofEarth'smagne;cfieldathighla;tudesshapesareaofpeakstrengthintoasmilepoin;ngtotheEquator[3,5].
[3] Min, Gyung Chan, et al. "Development of the HEMP Propagation Analysis and Optimal Shelter Design, Simulation Tool." (2013) [4] Longmire, Conrad L. "Justification and Verification of High-Altitude EMP Theory, Part I." (1987) [5] "The Late-Time (E3) High-Altitude Electromagnetic Pulse (HEMP) and Its Impact on the U.S. Power Grid." (2010)
Page 7
NuclearHEMPTestCases
• USA,JohnstonAtoll,1962(codenameStarfish):1.4MTnucleartest,400kmal3tude,effectsinHawaii(1450kmaway):1-3%streetlightsfailed,circuitbreakerstripped,burglaralarmstriggered,andtelecommunica3onsrelaydamaged[6];
• Russia,1962(SovietProjectK):300kTnucleartest,al3tudes300km,150km,and60kmincluded:damagetoundergroundcables600kmfarburied90cmdeep;abovegroundtelecomlines;surgearrestorburnout;spark-gapbreakdown;blownfuses;anddamagedMilitarygeneratorsandsubsta3ons.Earth’smagne3cfieldthereisgreaterthanatJohnstonAtoll[7];Ø Sovietscien3st(A)interviewedbyAmericanscien3st(Q)aperendofUSSR[7]:
"Q:WouldyoumakeajudgmentonwhetherearlyorlateEMPcausedthedamage? A:TheairlinewasdamagedbyearlyEMPandthecablebylate-arrivingEMP.(…) Q:WerethemilitarygeneratorsdamagedbyearlyorlateEMP? A:Early.(…) Q:Isthenorth-southandeast-westorienta3onoflinesimportant? A:Definitelyyes.Theyareunambiguously3edtothegeomagne3cfield."
[6] Foster Jr, John S., et al. "Report of the commission to assess the threat to the united states from electromagnetic pulse (emp) attack." (2004) [7] US-Russian meeting "HEMP effects on national power grid & telecommunications." (1995)
Page 8
HEMP’sEffectsonDevices
• Integratedcircuitswithshort-signalpaths=>high-frequencyEMP;• Largeelectricalsystems=>lowfrequencyEMP;• Pulseshigherthan10kV/msufficienttocausewidespreaddamage[8];• Wiresrunningthroughaffectedareaserveasantennae[9];• Hardening:protec3vemetallicshielding,specialsurgeprotectors,wire
termina3onprocedures,screenedisolatedtransformers,sparkgaps,etc.;• HardeningincreaseelectronicresistancetoEMP[7].
[7]US-Russianmee3ng"HEMPeffectsonna3onalpowergrid&telecommunica3ons."(1995)[8]HouseMilitaryResearch&DevelopmentSubcommi9ee,"ThreatsPosedbyElectromagne3cPulsetoU.S.MilitarySystems"(1997)[9]CarloKopp,"TheElectromagne3cBomb:AWeaponofElectricalMassDestruc3on."(1996)
Page 9
PossibleHEMPEffectontheConnec3vity
x
Internet2Topology[10].
(A)Texasisfullycompromised.
(B)Texasispar3allycompromised.(C)S3llsomeconnec3vityinTexas.
[10]Internet2NetworkInfrastructureTopology(2015)
Page 10
RestoringConnec3vityviaOtherMeans
LEO
MEO
GEO
Page 11
SatellitesSatelliteQuickFacts[11]:i. Opera(ngSatellitesbyCountry
ii. AmericanSatellitesbyOwner/Operator
iii. SatellitesbyTypeofOrbit
USA Russia China Other Total
549 131 142 483 1305
LEO(160-2000km) MEO(2000-35000km) HEO(HighlyEllip(cal) GEO(35786km)
696 87 41 481
Civil Commercial Government Military
21 250 126 152
[11]UnionofConcernedScien3sts(2015)
Page 12
SatelliteConstella3onExample:Iridium
• EachIRIDIUMsatellitemaintainsuptofourInterSatLinkseach(exceptforplanes1and6)[12];
• 6orbits,11satellitesperorbit,each4400kmapart,100.3minutesperiod[12].
(D)Averageend-to-enddelays.
(A)Orbits(planes)seenfromPole. (B)FootprintofeachSatellite. (C)Iridium’sorbitalmo3on[15].
[12]Pra9,StephenR.,etal."Anopera3onalandperformanceoverviewoftheIRIDIUMlowearthorbitsatellitesystem."(1999)[15]GlobalTelesatCommunica3ons,"IridiumSatelliteConstella3on."(2012)
Page 13
HEMP’sImpactonSatellites2DviewofHEMPatgroundlevel
3DviewofHEMP
Page 14
HEMP’sImpactonSatellites
• Immediatedirect,line-of-sightexposuretonuclearradia3onpulses:• X-ray,ultraviolet,gamma-ray,andneutron
pulses;
• Sizeofhazardzonedependsonweaponyield,detona3onal3tude,andthedegreeofsatellitehardeningagainstdisrup3onorharm[13];
• Damage:• Structuresandcoa(ng:solarpanelsand
sensorop3csifX-rayandUVfluxestoohigh;• Electronics:X-rayandGammaradia3on
inducedestruc3vecurrents.
[13]FosterJr,JohnS.,etal."Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3cpulse(emp)a9ack:Cri3calna3onalinfrastructures."(2008)
Page 15
HEMP’sImpactonSatellites
• Earthhasnaturallyoccurringradia3onbelts;
• EMPbeltsarecausedbyfreeelectronsreleasedindetona3on;
• Impactdependsonrepeatedpassagesthroughbeltcumula3vely;
• Characteriza3onofspa3alandtemporalproper3esiscomplex;
• Intensi3esofradia3onbeltsdependstronglyonburstla3tude[13].
[13]FosterJr,JohnS.,etal."Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3cpulse(emp)a9ack:Cri3calna3onalinfrastructures."(2008)
Page 16
HEMP’sImpactonSatellites:Beltexposureeffects
EventTime-to-failure(days)
NOAA(LEO800km)
TERRA(LEO700km)
ISS(LEO322km)
5MT@200km 0.1 0.1 0.1
0.8MT@368km 1 1 0.5
0.8MT@491km 1 1 1
4.5MT@102km 0.1 0.2 0.2
4.5MT@248km 0.1 0.2 0.2
0.03MT@500km 40 100 150
0.1MT@200km 10 17 20
• NOAA,TERRAandISSareallhardened,specificallybuiltsatellites(whichmaynotbethecaseforcommercialsatellites)
Time-to-failuresofsatellitesduetodifferentsimulatedHEMPevents[13]:
[13]FosterJr,JohnS.,etal."Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3cpulse(emp)a9ack:Cri3calna3onalinfrastructures."(2008)
Page 17
HEMP’sImpactonSatellites:Line-of-sighteffects
Satellite EventProbabilityofDamage(%)
Thermo-mechanical SGEMP/burnout Latch-up/burnout
ISS(LEO322km)
4.5MT@248km 1.7 4 4.2
1MT@300km 0 5 5
0.1MT@120km 0 3 4
5MT@200km 1.7 5 5
NOAA(LEO800km)
1MT@300km 0.2 19 20
0.1MT@120km 0 3 5
5MT@200km 1 7 8
TERRA(LEO700km)
1MT@300km 0.3 18 18
0.1MT@120km 0 2 5
5MT@200km 1.2 7 7
*Thelikelihoodthatonespecificsatellitewillbeinline-of-sightoftheexplosionrangesfrom5to20%,reducingalottheprobabili3esabove.Infact,anysatellitethatisindirectline-of-sightandrela3velyclose(LEO)willalmostcertainlyfailimmediately[13].
Riskofimmediatedamageofsatellitesduetodifferentsimulatedevents[13]:
[13]FosterJr,JohnS.,etal."Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3cpulse(emp)a9ack:Cri3calna3onalinfrastructures."(2008)
Page 18
• SatellitesinLEOaremuchmoresuscep3bletodamagefrombothdirectandpersistentradia3on;
• SatellitesatGEOaretypicallyhardenedtoagreaterextentthanLEO;• Line-of-sightexposureofLEOtoexplosion=>immediatelossofmany
opera3onalcapabili3es,aswellaslossofpowergenera3ngcapacity;• Weaponsfrom10kTto100kT:EMPa9acksovertheNortherncon3nentalUS
orCanadaindicateslesserrisktoLEOsatellites[13];• Satellitesinorbitalreadydepletedapor3onoftheiran3cipatedservicelife;• 1962,StarfishPrime:21satellitesinorbit(orlaunchedinthefollowingweeks,
consis3ngof20LEO+1MEO),8weredamagedandcompromisedorterminatedtheirmissions[14];Ø Informa3onabouttheother13isnotpubliclyavailable.
HEMP’sImpactonSatellites
[13]FosterJr,JohnS.,etal."Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3cpulse(emp)a9ack:Cri3calna3onalinfrastructures."(2008)[14]Brown,W.L.etal,"CollectedPapersontheAr3ficialRadia3onBeltFromtheJuly9,1962,NuclearDetona3on."(1963)
Page 19
PossibleHEMPeffectonIridiumconstella3on[12]includeimpairment/destruc3onofsatellites:
Post-HEMPRestora3onwithSatelliteAssistance
[12]Pra9,StephenR.,etal."Anopera3onalandperformanceoverviewoftheIRIDIUMlowearthorbitsatellitesystem."(1999)
Page 20
t=0minIni(ally,LEOsatellitecoveragewouldbelost:
Post-HEMPRestora3onwithSatelliteAssistance
Page 21
t=15minAsorbitsrotate,LEOcoveragewouldberegainedahersome(mefroms(llfunc(oningsatellites:
Post-HEMPRestora3onwithSatelliteAssistance
Page 22
t=30minCompleteLEOcoveragewouldbeachievedahersomemore(me:
Post-HEMPRestora3onwithSatelliteAssistance
Page 23
t=1h30minWiththeorbitalmovement,defec(veLEOsatelliteswouldperiodicallycomeback:
Post-HEMPRestora3onwithSatelliteAssistance
Page 24
Challenges
Determiningexactimpactonsatellitesconstella3oniscomplex
Be9erhardenedconstella3ons(likelysurvivors)aremilitary/governmentandwillprobablybeoverflowedbymilitary/high-prioritytraffic
GEOimposesahighdelay,limi3ngsometypesof2-waycommunica3ons
SinceGEOsatelliteswouldlikesurvive,themajorityoftrafficwouldberoutedthroughthemwheneverpossible(possiblebo9leneck)
CommercialLEOconstella3ons(providesmallerdelays)arelikelytosufferbig"holes"incoverage
Post-HEMPRestora3onwithSatelliteAssistance
[16]Amos,Jonathan,"ViasatBroadband'super-satellite'Launches."(2011)[17]O3bNetworks,"O3bTechnology-O3bNetworks."(2015)
Opportuni(es
Satelliteorbitsareknown,periodic,andwelldefined
Trafficschedulingcanbeusedtosendtrafficflowsthroughconnectedpartsoftheconstella3on,intermi9ently
DelayTolerantNetworksmighthelpensurethatpacketsarriveattheirdes3na3onsinbadlydisruptednetworksthroughseveralLand-Satellite-Landhops
StateoftheartHighThroughputSatellites(HTS)offerupto134GBpsinGEO(ViaSat1[16])andmorethan10Gbpspersatellitewithguaranteedlatencybelow150msinLEO(O3b[17],launchedin2014)
Page 25
t=15min
ProposedSolu3on:Post-HEMPRestora3onwithSatelliteAssistance
SurvivednodesbufferthetraffictobesentoutsideofthedamagedareaoncethereisLEOsatelliteconnec(on:
Page 26
t=30minAscoverageisslowlyregained,buffernodesbeginevacua(ngqueuestonearest(minimum
delay)LEOsatellitelandsta(onofmainnetwork:
ProposedSolu3on:Post-HEMPRestora3onwithSatelliteAssistance
Page 27
t=35minWhilehavingLEOsatelliteconnec(on,queuesareevacuatedbasedonthepriorityof
emergencycommunica(on:
ProposedSolu3on:Post-HEMPRestora3onwithSatelliteAssistance
Page 28
t=1h10minAsLEOconstella(on"hole"approaches,mainnetworkisinformedandschedulingstarts
again:
ProposedSolu3on:Post-HEMPRestora3onwithSatelliteAssistance
Page 29
t=1h25minDuringlackofLEOcoverageperiod,flowsarebufferedaccordingtoanpre-determined
emergencypreferencetrafficpolicy:
ProposedSolu3on:Post-HEMPRestora3onwithSatelliteAssistance
Page 30
Objec(veMaximizethecon3nuityofmission-cri3calservicesconsideringtheirQoSrequirements(delay-tolerant,degraded-servicetolerant)withundamagedterrestrialandnon-terrestrialcommunica3oninfrastructureaperaHEMPa9ack;• Given
§ Networktopologies(originalandpost-HEMPsub-network)§ Bufferingcapabili3esofnetworknodes;§ Knowledgeofunaffectedsatellitesandtheirorbits/posi3ons/speed/throughput;§ Trafficpriority(Telecommunica3onServicePriorityTSP[18],emergencydata,and
otherhighlyimportanttraffic,asSCADAdata)• Constraints
§ Throughputanddelaysofsatellitenetwork;§ Degraded-servicetoleranceandlatencysensi3vityoftrafficbeingqueued;§ Bufferingcapabilityofnodes;
ExpectedOutputIntelligentQoS-awaretrafficschedulingmethodtomaximizethroughputwhileprovidingmission-cri3calservicesatleasttheirminimumrequirementintermsofdelayandthroughput.
ProposedSolu3on:Post-HEMPRestora3onwithSatelliteAssistance
[18]HomelandSecurity,"Telecommunica3onsServicePriority(TSP)."(2013)
Page 31
Delay/DisruptTolerantNetworks(DTN)
• ChallengedInternetworks:latency,bandwidthlimita3ons,systemconnec3vity,errorprobability,nodelongevity,and/orpathstabilitysubstan3allyworsethantypicalnetworks(Internet);
• BundleProtocol,“overlay”architecture:operatesaboveexis3ngprotocolstack,providingstoreandforwardgatewayfunc3onbetween“bundleforwarders”;
• Opportunis3corpredictablecontacts,parameterizedby:start/end3mes,capacity,latency,endpoints,direc3on;
Isolatednetworkfragment
Mainnetwork
RegionA RegionCRegionBandB’DTNGateways
DTNGateway
[19]Fall,Kevin."Adelay-tolerantnetworkarchitectureforchallengedinternets."Proceedingsofthe2003conferenceonApplica3ons,technologies,architectures,andprotocolsforcomputercommunica3ons.ACM,2003.
Isolatednetworkfragment
GEO
LEO
RegionA’
Page 32
Delay/DisruptTolerantNetworks(DTN)
• TrafficvsData:whateverhashigherpriorityandcancopewiththelatency,transmissiondelays,intermi9entbehaviormaygetqueued(simplifica3on);
• BPkeyunitoftransferisthebundle:canbestoredinmul3plenodesandfragmented;
• Rou3ng:rangesfromzeroknowledgeofnetwork(onlyonopportunis3ccontacts)tototalknowledgeofnetwork(onlydeterminis3ccontacts);
[20]Arani3,Giuseppe,etal."Contactgraphrou3nginDTNspacenetworks:overview,enhancementsandperformance."Communica3onsMagazine,IEEE53.3(2015):38-46.
Page 33
ContactGraphRou3ng• Dynamicrou3ngparadigmthatcomputesroutesthrough3me-varyingtopologyof
scheduledcommunica3oncontactsinaDTNarchitecture(onlyplanned/scheduledtopologychanges);
• EachnodeexchangeswitheveryothernodeContactPlanMessages,twotypes:§ Contactmessage:beginningandendof3meintervalforthemessage;
transmi�ngandreceivingnodes;plannedtxrate;§ Rangemessage:beginningandendof3meintervalforthemessage;
transmi�ngandreceivingnodes;an3cipateddistancebetweenthenodesduringtheinterval;
• WiththeContactPlan,eachnodebuildsarou3ngtablelis3ngallroutesfromittoallothernodes(eachdes3na3onnodecontainingpossiblymul3pleroutes,oneforeachlocalneighbor).Also,eachrouteentryshows:§ Allothernodesoftheroute;§ Latencyoftheroute;§ Thelatest3metherouteisavailable;
• Toperformtheabove,aContactGraphisgenerated.Thisgraphneedstobeupdatedasnodesgooutofrangeandtransmitstop3mesarereached.
[20]Arani3,Giuseppe,etal."Contactgraphrou3nginDTNspacenetworks:overview,enhancementsandperformance."Communica3onsMagazine,IEEE53.3(2015):38-46.[21]Seguí,S.,andEstherH.Jennings."ContactGraphRou3ng."NASATechBriefs(2011):15.
Page 34
ContactGraphRou3ng• Well-formedroutes:sequenceofcontacts,noloops;• Expira(on(me:crea3on3me+TTLofbundle;• OneWayLightTimemargin:maxdistancevaria3onduringtransmission;• Lastmoment:deadlinetoreceive–(OWLT+OWLTmargin)[ifcontactmomentis
smallerthanlastmoment,notransmission];• Contactcapacity:txrate*dura3on;• Es(matedcapacityconsump(onforabundle:includesoverhead;• Residualcapacityofacontact:(totalcontactcapacity)–(ECCofhigherpriority
bundles);• Plausibleopportunity:contactwhoseresidualcapacitygreaterthanbundle’sECC;• Plausibleroute:sendertodes3na3onseriesofplausibleopportuni3es;• Forfeit(me:momentabundlehastobesentinordertofollowaplausibleroute;• Excludednodes:listofnodesthroughwhichbundlewon’tgothrough;• Cri(calbundle:highestprioritybundle.
[20]Arani3,Giuseppe,etal."Contactgraphrou3nginDTNspacenetworks:overview,enhancementsandperformance."Communica3onsMagazine,IEEE53.3(2015):38-46.[21]Seguí,S.,andEstherH.Jennings."ContactGraphRou3ng."NASATechBriefs(2011):15.
Page 35
ContactGraphRou3ng:TheAlgorithm
Ini(aliza(on:Setdes3na3onDtobundle'sfinaldes3na3onnode;setdeadlineXtobundle'sexpira3on3me;createemptyRou3ngTable;setforfeit3metoinfinityforeverydes3na3on;andcreatealistofExcludedNodes.
ContactReviewProcedure:Inthisstep,eachnodecreates/updatesaDAG“ContactGraph”.Itsrootisavirtualself-to-selfcontactandtheotherver3cesareallothercontactsthatmightcontributetoreachsomeothernode.Virtualendingver3cesrepresen3ngcontactfromnodeA-to-nodeAarealsoincluded.Foreachdes3na3onD,Dijkstraisrunitera3vely(each3meremovingtheini3alcontact)un3lnomoreroutesarefound.EachbestrouteforeachcontactisaddedtotheRou3ngtableintheentryoftherespec3vedes3na3onnode.Eachoftheseroutesneednotbecon3nuousateveryinstant(allnodesarecapableofstoring).
ForwardingDecision:Amongtheavailableroutes,choosetheonewiththelowestcostandqueuethebundlefortransmissioninthatroute’sentrynode.Ifanyrouteforfeit3meisreachedandthere’ss3llbundlesinitsqueue,lookforanewrouteforthosebundles.
[20]Arani3,Giuseppe,etal."Contactgraphrou3nginDTNspacenetworks:overview,enhancementsandperformance."Communica3onsMagazine,IEEE53.3(2015):38-46.[21]Seguí,S.,andEstherH.Jennings."ContactGraphRou3ng."NASATechBriefs(2011):15.
Page 36
ContactGraphRou3ng:Pros&Cons
PROs
Highconfidenceduetoaccurateinforma3on
Eventhoughthecurrenttopologydoesn’tnecessarilyreflecttheroutesbeingcalculated,iteventuallywill.
Changestotopologycanbemul3castedsothatallnodescanupdatetheirDAGs
Delayofotherbundlesintheoutboundbuffer:ContactGraphRou3ng-EarliestTransmissionOpportunity[20]
CONs
Considerallnodesabletostoreandforward
Considernodesonlyhaveonecontactata3me(nooneP2Mdownlink,norM2Muplink)
Noopportunis3ccontactsconsidered
Noadvantagesofperiodicityofcontacts
Noestablishedini3aliza3onprotocoltoexchangeContactmessages
Rou3ngdecisionsonlybasedonlocalknowledgemightnotmaximizetraffic
[20]Arani3,Giuseppe,etal."Contactgraphrou3nginDTNspacenetworks:overview,enhancementsandperformance."Communica3onsMagazine,IEEE53.3(2015):38-46.[21]Seguí,S.,andEstherH.Jennings."ContactGraphRou3ng."NASATechBriefs(2011):15.
Page 37
Objec(veMaximizethebundletrafficsentfrom/totheisolatednetworkstothemainnetwork;Given
§ Networktopologies(originalandpost-HEMPsub-network);§ Ini3allysingleisolatednetwork;§ Bufferingcapabili3esofnetworknodes(unlimitedontheground,zeroonsatellites);§ Knowledgeofunaffectedsatellitesandtheirorbits/posi3ons/speed/throughput;§ Bundlepriority(Telecommunica3onServicePriorityTSP[18],emergencydata,and
otherhighlyimportanttraffic,asSCADAdata);§ Singlesatellitegroundsta3onsperisolatednetwork;
• Constraints§ Throughput,delays,contact3mesofsatellitenetwork;§ Degraded-servicetoleranceandlatencysensi3vityoftrafficbeingqueued;
ExpectedOutputTrafficschedulingmethodtominimizethetotalunusedcapacityoftheEarthtosatellite,satellitetosatellite,andsatellitetoEarthlinkswhilerespec3ngbundlepriori3es.
Ini3alApproach
Page 38
1. Immediatelybefore/duringtheEMPaVack(verysmallwindow):trytoevacuatedataaccordingtoSifat/Carlosproposals;
2. AhertheEMPaVack:1. Ini(alize:CommunicateallaffectednodesthroughwhateverGEOsatellites
availableinordertoexchangetheirloca3ons,priori3es,andgettoknowwherearethepossibletrafficevacua3onpointsinthemainnetwork;
2. WithknowledgeofLEO/MEO/GEOorbitsandwhatpor3onofthemweredestroyed(alsotheirthroughputcapaci3esandlatency):1. Sendhighpriority/highlatencyelas3citytoGEO2. Sendmedium/lowpriorityandmedium/highlatencyelas3citytoMEO,usingspecific
rou3ngapproach3. Sendlowlatencyelas3citytrafficwhenwithLEOcoverageandinfiniteelas3citytraffic
always(tobequeuedwhenwithoutLEOcoverage)
OverallApproach
Page 39
Rou3ngApproach1:ModifyCGRtoaccountfortheobjec3vesandspecificscenario.(S3llalocalknowledge
situa3on).Rou3ngApproach2(Possibly):
Implementvaria3onofMax-Flowalgorithmincarefullyelaboratedgraphwhereedgesencompasscontactstart/end3mes,capaci3es,andlatencies.
Ini3alApproach
Isolatednetworkfragment
Mainnetwork
SatelliteGroundSta(ons
SatelliteGroundSta(on
Satellites
Isolatednetworkfragment
Page 40
References1/2[1]Miller,ColinR.Electromagne3cpulsethreatsin2010.AIRWARCOLLMAXWELLAFBAL
CENTERFORSTRATEGYANDTECHNOLOGY,2005.[2]Wilson,Clay."High-al3tudeelectromagne3cpulse(HEMP)andhighpowermicrowave(HPM)
devices:Threatassessments."LIBRARYOFCONGRESSWASHINGTONDCCONGRESSIONALRESEARCHSERVICE,2008.
[3]Min,GyungChan,YeongKwanJung,andJeong-JinKang."DevelopmentoftheHEMPPropaga3onAnalysisandOp3malShelterDesign,Simula3onTool"KTIHEMPCORD"."(2013).
[4]Longmire,ConradL."Jus3fica3onandVerifica3onofHigh-Al3tudeEMPTheory,PartI."LawrenceLivermoreNa3onalLaboratory,Livermore,CA,UCRL-15938(1987).
[5]ReportMeta-R-321:"TheLate-Time(E3)High-Al3tudeElectromagne3cPulse(HEMP)andItsImpactontheU.S.PowerGrid"January2010.Wri9enbyMetatechCorpora3onforOakRidgeNa3onalLaboratory.
[6]FosterJr,JohnS.,etal."Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3cpulse(emp)a9ack."Cri3calNa3onalInfrastructuresReport1(2004).
[7]SUBJECT:US-Russianmee3ng–HEMPeffectsonna3onalpowergrid&telecommunica3onsFrom:HowardSeguine,17Feb.1995MEMORANDUMFORRECORD
[8]HouseMilitaryResearch&DevelopmentSubcommi9ee,ThreatsPosedbyElectromagne3cPulsetoU.S.MilitarySystemsandCivilianInfrastructure,StatementofDr.LowellWood,July16,1997,63.Availablefromh9p://commdocs.house.gove/commi9ees/security/has197010.000/has197010_Of.htm
[9]CarloKopp,"TheElectromagne3cBomb:AWeaponofElectricalMassDestruc3on,"(Fairbairn,Australia:RAAFAirPowerStudiesCentre,1996),2.Availablefromh9p://www.airpower.maxwell.af.mil/airchronicles/kopp/apjemp.html.
Page 41
References2/2[10]Internet2,"Internet2NetworkInfrastructureTopology".1June2015.Web.Availablefrom:h9ps://
www.internet2.edu/media/medialibrary/2015/08/04/NetworkMap_all.pdf[11]UnionofConcernedScien3sts,"UCSSatelliteDatabase."31Aug.2015.Web.Availablefrom:h9p://
www.ucsusa.org/nuclear-weapons/space-weapons/satellite-database.html[12]Pra9,StephenR.,etal."Anopera3onalandperformanceoverviewoftheIRIDIUMlowearthorbitsatellite
system."Communica3onsSurveys,IEEE2.2(1999):2-10.[13]FosterJr,JohnS.,etal.Reportofthecommissiontoassessthethreattotheunitedstatesfromelectromagne3c
pulse(emp)a9ack:Cri3calna3onalinfrastructures.ELECTROMAGNETICPULSE(EMP)COMMISSIONMCLEANVA,2008.
[14]Brown,W.L.,W.N.Hess,andJ.A.VanAllen,"CollectedPapersontheAr3ficialRadia3onBeltFromtheJuly9,1962,NuclearDetona3on,"JournalofGeophysicalResearch68,605,1963.
[15]GlobalTelesatCommunica3ons,"IridiumSatelliteConstella3on."GlobalTelesatCommunica3ons,7Aug.2012.Web.Availablefromh9ps://www.youtube.com/watch?v=MGJal5uPXRA
[16]Amos,Jonathan,"ViasatBroadband'super-satellite'Launches."BBCNews.BBCNews,20Oct.2011.Web.Availablefrom:h9p://www.bbc.com/news/science-environment-15358121
[17]O3bNetworks,"O3bTechnology-O3bNetworks."O3bNetworks,16Sept.2015.Web.Availablefrom:h9p://www.o3bnetworks.com/technology/
[18]HomelandSecurity,"Telecommunica3onsServicePriority(TSP)".HomelandSecurity,7May2013.Web.Availablefrom:h9p://www.dhs.gov/telecommunica3ons-service-priority-tsp
[19]Fall,Kevin."Adelay-tolerantnetworkarchitectureforchallengedinternets."Proceedingsofthe2003conferenceonApplica3ons,technologies,architectures,andprotocolsforcomputercommunica3ons.ACM,2003.
[20]Arani3,Giuseppe,etal."Contactgraphrou3nginDTNspacenetworks:overview,enhancementsandperformance."Communica3onsMagazine,IEEE53.3(2015):38-46.
[21]Seguí,S.,andEstherH.Jennings."ContactGraphRou3ng."NASATechBriefs(2011):15.
Page 42
Thankyou!