《网络的核心机制》ppt课件

《《网络的核心机制》ppt课件》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、P2P网络的核心机制1章节内容4.1覆盖网拓扑结构4.2分布式散列表4.3路由和定位4.4查询和搜索4.5动态结点算法4.6容错性24.1覆盖网拓扑结构P2P网络是构建在底层物理网（如IP网）上的应用层覆盖网，拓扑结构对P2P网络的工作性能以及设计机制有决定性作用典型拓扑结构：带弦环、树、PlaxtonMesh、环面、超立方体、蝴蝶、异或问题：拓扑结构对P2P性能的影响情况？Geometries'NatureFNSFRSPerformanceResilienceLatency3Geometriescon

2、sideredGeometryAlgorithmRingChord,SymphonyHypercubeCANTreePRRHybrid=Tree+RingTapestry,PastryXORd(id1,id2)=id1XORid2Kademlia4Geometry=>Flexibility=>PerformanceGeometrycapturesflexibilityinselectingalgorithmsFlexibilityisimportantforroutingperformanceFlexi

3、bilityinselectingroutesleadstoshorter,reliablepathsFlexibilityinselectingneighborsleadstoshorterpaths5MetricsforflexibilityFNS:FlexibilityinNeighborSelection=numberofnodechoicesforaneighborFRS:FlexibilityinRouteSelection=avg.numberofnext-hopchoicesforall

4、destinationsConstraintsforneighborsandroutesselectneighborstohavepathsofO(logN)selectroutessothateachhopisclosertodestination6SummaryofflexibilityanalysisFlexibilityOrderingofGeometriesNeighbors(FNS)Hypercube<

5、<

6、overyfinishescaptureshowquicklyrecoveryalgorithmsneedtoworkdependsonFRSEvaluation:Failafractionofnodes,withoutrecoveringanystateMetric:%PathsFailed8DoesflexibilityaffectStaticResilience?Tree<

7、dFRScanreducelatencyTreehasFNS,HypercubehasFRS,Ring&XORhavebothMetric:OverlayPathLatency10Whichismoreuseful:FNSorFRS?Plain<

8、madietal.03]K.P.Gummadi,R.Gummadi,S.D.Gribble,S.Ratnasamy,S.ShenkerandI.Stoica.TheImpactofDHTRoutingGeometryonResilienceandProximity.InSIGCOMM2003,pp.381-394.124.2分布式散列表分布式散列表(DHT，Distributedhashtable)是P2P网络的核心设施，它基于一致性散列函