Routing and Spectrum Allocation for Multicast Traffic in Elastic...
Transcript of Routing and Spectrum Allocation for Multicast Traffic in Elastic...
RoutingandSpectrumAllocationforMulticastTrafficinElasticOpticalNetworks
Presenter: AnliangCAISupervisor: Prof.MosheZUKERMANCity University of Hong Kong1February2018
Supported by a grant from RGC of HK SAR (CityU 11216214)
Outline
ØIntroductionØOptimalProvisionofaMulticastDemandØLight-Tree-BasedEONDesignØProvisioningMulticastinEONwithSharedProtection
ØConclusions
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Introduction – Traffic Increase
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Bigdata Cloudcomputing UHDvideo Virtualreality
Rapidtrafficgrowth– Zettabyteera• AnnualglobalIPtrafficwillreach2.3
Zettabytesby2020• Compoundannualgrowthrate:22%
Credit: http://www.pacsquare.com/; https://www.pinterest.com/; http://www.alphafinity.com/; Cisco, “Cisco visual networking index: Forecast and methodology, 2015–2020,” 2016.
Introduction (Cont.)• Diversetraffic• Elastic optical networks(EONs)
– Flexible frequency grid– Better spectrum utilization– ……
4M. Jinno et al., IEEE Commun. Mag., 48(8), pp. 138-145, 2010.K. Christodoulopoulos et al., J. Lightw. Technol., 29(9), pp.1354-1366, 2011.
Frequencyslot(FS):A unittoquantizethespectralresources
Elastic
frequency
WDM
frequencyw1 w3w2
Bandwidth saving
50 GHzExsiting ITU-T fixed grid
New flexible grid
100 Gbps
10 Gbps
40 Gbps
50 GHz 50 GHz
50 GHz
30 GHz
10 GHz
Spectrumresourcesinopticalfibers
Routing & Spectrum Assignment (RSA)• Routing– findapath,e.g.,byDijkstra’salgorithm• Spectrumassignment
– Spectrumcontinuity:assignsameFSsinalltraversedlinks– Spectrumcontiguity(𝑓", 𝑓$ not𝑓", 𝑓%)– Spectrumnon-overlapping:any FSina fibercannotbeallocatedtotwoor
moreconnections
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Optical fiber
BVT
BV-OXC
IP router
Node B
Node C
Node D
Node ABVT: Bandwidth-Variable TransponderBV-OXC: Bandwidth-VariableOptical Cross Connect
Lightpath2:BàC
…
…
f6f7
Lightpath 1: AàC
f1f2f3
f1f2f3
Lightpath:anopticalchannelbetweentwonodes
Overview• DesignanEONwithprotectionformulticast
– Comparethreetechnologiesforprovisioningmulticast– ProposeefficientheuristicalgorithmtodesignEONs– Extendthenetworkdesignwithprotection
• Problemstatement– Given:anetworkandmulticasttrafficdemand(s)– Objective:minimizenetworkresourceusage
• Methodology:mixedintegerlinearprogramming(MILP)formulationandheuristicalgorithm
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OutlineØIntroduction
ØOptimalProvisionofaMulticastDemand
ØLight-Tree-BasedEONDesignØProvisioningMulticastinEONwith SharedProtection
ØConclusions
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Optimal Provision of a MulticastDemand• Multicasttraffic:data transmittedfromonesourcetomultipledestinations,e.g.,𝐴 → 𝐵, 𝐶, 𝐸
• Bandwidth-intensive multicastservices– UHD TVdelivery,inter-datacentersynchronization,video conferencing,etc.
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ASource
C Destination2
E Destination3
F
BDestination1
D
1
5
3
0
4
9
6
2
8
10
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InterDatacenterNetwork
Provisioning Technologies for Multicast• Lightpath:separatelightpaths todestinations• Light-tree:extensionoflightpath – viaatreestructure,tree
nodescanreceivesignalcopies• Light-trail:extensionoflightpath – viaatrailstructure,trail
nodescanreceivesignalcopies
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I. Chlamtac et al., IEEE Trans. Commun., 40(7), pp. 1171—1182, Jul. 1992.L. H. Sahasrabuddhe and B. Mukherjee, IEEE Commun. Mag., 37(2), pp. 67–73, Feb. 1999.A. Gumaste and I. Chlamtac, IEEE HPSR, 2003, pp. 251–256.
Lightpath Light-tree Light-trail
source
destination
Distance-Adaptive Transmission (DAT)• Transmissions of shorter paths
can use higher level Modulation Schemes (MSs)
• For a given data rate, the higher level the modulation, the less bandwidth requirement
• For a light-tree/light-trail, MS assignment is subject to the longest distance among the transmissions to all destinations
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K. Christodoulopoulos et al., J. Lightw. Technol., 29(9), pp.1354–1366, 2011.C. Wang et al., J. Lightw. Technol., 33(14), pp. 2955–2964, 2015.K. Walkowiak et al., IEEE Communi. Lett., 18(12), pp. 2117–2120, Dec. 2014.
DATModelModulationScheme
TransmissionDistance
CapacityperFS
BPSK 4000 12.5Gb/s
QPSK 2000 25Gb/s
Example:40-Gb/sconnections
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1
2
5
4
6
1200
1500
1500
1200
1200
1200
1200
1200
2700 km
1200 km
BPSK
QPSK
1200 km 2700 kmMustchooseBPSK
L4 L3 L2 L1….
L1>L2>L3>L4>….….
BPSKQPSK8QAM16QAM
Modulation Level
Transparent Reach
Lightpath Technology with DAT• Example:𝐴 → 𝐵, 𝐶, 𝐷 requesting30Gb/s• Lightpath scheme:separatelightpaths formulticast
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Optical Fiber
BVT
Client
Lightpath 2
Lightpath 1
Node B
Node C
Node D
Node A
BVT: Bandwidth-Variable TransponderBV-OXC: Bandwidth-Variable
Optical Cross Connect
Lightpath 3
BV-OXC
Usage:3transmitters8FSs
8QAM
BPSK
8QAM
Light-Tree Scheme with DAT• Asinglelight-tree
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Optical Fiber
BVT
MC-OXCClient
Light-tree 1
Node B
Node C
Node D
Node A
BVT: Bandwidth-Variable TransponderMC-OXC: Multicast-Capable
Optical Cross Connect
Usage:1transmitter9FSs
Notnecessarilymorespectrumefficientthanthelightpath scheme
BPSK
Multi-Light-Tree Scheme with DAT• Multiplelight-trees
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Optical Fiber
BVT
ClientLight-tree 2
Light-tree 1
Node B
Node C
Node D
Node A
BVT: Bandwidth-Variable TransponderBV-OXC: Bandwidth-Variable
Optical Cross Connect
MC-OXC
Usage:2transmitters7FSs
BPSK
8QAM
Light-Trail Scheme with DAT• Asinglelight-trail
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Optical Fiber
BVT
Client
Light-trail 1
Node B
Node C
Node D
Node A
BVT: Bandwidth-Variable TransponderMI-OXC: Multicast-Incapable
Optical Cross Connect
MI-OXC
Usage:1transmitter12FSs
BPSK
Multi-Light-Trail Scheme with DAT• Multiplelight-trails
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Optical Fiber
BVT
ClientLight-trail 2
Light-trail 1
Node B
Node C
Node D
Node A
BVT: Bandwidth-Variable TransponderMI-OXC: Multicast-Incapable
Optical Cross Connect
MI-OXC
Usage:2transmitters7FSs
BPSK
8QAM
Results – Six-Node Networks• Transmitterusage:lightpath ≥multi-light-trail≥multi-light-tree≥ light-tree= light-trail
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3 4
1 2
5 6
3 4
1 2
5 6
3 4
1 2
5 6
Results – Six-Node Networks (Cont.)
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3 4
1 2
5 6
3 4
1 2
5 6
3 4
1 2
5 6
Results – Real-Size Networks• Multi-light-tree,multi-light-trail,light-treeschemesshowcomparableperformance,whilelight-trailistheworst,lightpath liesinbetween
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COST239 USNET
Running Time
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Comparison of CPU Times in Units of Seconds by the Five Schemes in the USNET Network
Comparison of CPU Times in Units of Seconds by the Five Schemes in the COST239 Network
Benefit of DAT• Moresavingswithhighernetworkdensity• Lightpaths receivethemostsavingsforthehighestmodulationgain
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Spectrum Savings of Distance-Adaptive Spectrum Allocation for a Multicast Demand
OutlineØIntroductionØOptimalProvisionofaMulticastDemand
ØLight-Tree-BasedEONDesignØProvisioningMulticastinEONwith SharedProtection
ØConclusions
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Light-Tree-Based EON Design• Thelight-treescheme:satisfactoryperformanceinreal(sparse)networks
• Multiplemulticastdemands• Objective:minimizethemaximumspectrumrequiredinthelinks
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Optical fiber
BV-T
MC-OXC
IP routerLight-tree 1: Aà{C,D}
f8f9
Node B
Node C
Node D
Node A
f8f9
f8f9
Light-tree2:Bà{C}
f1f2f3 ……
Heuristic Algorithm• MILPisnotscalable,butforreal-sizeproblemswestillneedtominimizethespectrum.
• Weproposepolynomial-timeheuristicalgorithm,i.e.,DCMCT,andcompareittotheexistingalgorithms,namely,AFAandshortestpathtree.
• DCMCTaimsforahigher-levelMS– Higher-levelMS->fewerFSsperlink– Higher-levelMS->shorterreach ->shorterpath->smallertrees->fewerFSsintotal
– Butwemayneedlongerpath->lower-levelMS->currentresourcescanbereused
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Demand-Serving Order Matters!• Inourheuristicalgorithm,i.e.,DCMCT,weservethedemandsinanorder. Differentdemand-servingordersyielddifferentresults.
• Threeorderingmethods– _DO:arrangedemandsindecreasing orders– _n: Shufflethedemandstoobtainarandomlyorderedsequence.Tofurther improvethesolutionquality,weconsiderndemandsequencesforeachset
– _n_DO:nshuffledsequenceseachorderedby_DO24
DCMCTalgorithm
Input OutputAdemandsequence Result
r1
r2
r=min ri
D1D2D3D4D5S1
D3D4D5D1D2S2
Results – n6s9• Theeffectofthenumberofdemandsequencesontheheuristicperformance
• Gap totheoptimum: _1k(3%),_10k(1.8%)• 1,000demandsequences->sufficientlygood
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Results – n6s9 (Cont.)• DCMCT_1kisclosetotheoptimumandoutperformstheotheralgorithmsincludingtheexistingone
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Results – Real-Size Networks• Undercomparablerunningtime,DCMCT_y_DOperformsthebest
• Onaverage,AFAperformstheworst– Requiring11.7%(COST239),16.7%(USNET)morespectrumthanDCMCT_y_DO
– WorsethanDCMCT_DO(tensofmilliseconds)
27COST239 USNET
Results – Comparison Between DCMCTand Shortest Path Tree (SPT)• DCMCToutperformsSPTforallthecases
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COST239 USNET
OutlineØIntroductionØOptimalProvisionofaMulticastDemandØLight-Tree-BasedEONDesign
ØProvisioningMulticastinEONwith SharedProtection
ØConclusions
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Provisioning Multicast in EONs withShared Protection
• A link failure (e.g., a trunk of a multicast) couldresultinsevereservicedisruption
• Protection– enablenetworkstocontinuetooperateunderafailure
• Focus:single-linkfailure(dominantscenario)
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1
2
3
4
5
6
Source Destination
Shared Protection Scheme• Protectalight-treebyhavingeachofitsprimarypathsprotected
viaalink-disjoint backuppath– Link-disjoint:Nobackup path shares common link with itsprimarytree– Self-sharing(SS):The resources in alink allocated to a source-destination
pairprotectthe primary path of anotherSDpair
• Cross-sharing(XS):Multiple connections can share backup-onlyresources as long as they do not fail simultaneously
Anexampleforprotectionschemes:(a)afour-nodefully-meshnetwork;(b)link-disjoint;(c)self-sharing;and(d)cross-sharing.
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A
D
B
C(b) M1: A->{B,C}
B
C D(c) M2: B->{C,D}
A B
DC(d) M1&M2
Primary-only link
SS linkSS link
Backup-only link
XS link
Physical linkA
D
B
C(a) A four-node fully-mesh network
N. K. Singhal et al., Comput. Netw., 50(2), pp. 200-206, 2006.
Results – n6s9• Compared to the MILP, we propose polynomial
time heuristic, i.e., APPF_G – APPF_G_DO requires 11.8% more spectrum– APPF_G_100 requires 4.4% more spectrum
• 100randomsequencesareconsideredsufficienttoachievenearoptimum
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Results – COST239• APPF_G_4000savesonaveragearound9%spectrumcomparedtoAPPF_G_DO
• 4000randomsequencesachievenearperformanceto10000sequences,andareconsideredsufficient
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Results – USNET• Ourproposedalgorithmoutperformsthestraightforwardmethod
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OutlineØIntroductionØOptimalProvisionofaMulticastDemandØLight-Tree-BasedEONDesignØProvisioningMulticastinEONWithSharedProtection
ØConclusions
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Conclusions• Wecomparedthefiveschemesformulticastprovisioning– MILPformulationforthelight-trailtechnology– EvaluatedthebenefitofDATforthefiveschemes
• Wedesignedalight-tree-basedEON– AMILPformulationandanefficientheuristicalgorithm– Theproposedheuristicoutperformstheexistingones
• Weextendedthenetworkdesignwithprotection– Firstworkofthisimportantproblem– MILPformulationandheuristicalgorithm
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