CS551ISP Peering[Norton01]Bill Chenghttp://merlot.usc.edu/cs551-f121 Computer Communications - CSCI 551 Copyright © William C. Chengprovide connectivity to each others’ customersPeering:2Definitions Computer Communications - CSCI 551 Copyright © William C. Chengnon-transitive relationshipone ISP sells transit to another ISPTransit:has access to global routing tableTier-1 ISP: does not purchase transit from anyonePeering is not a transitive relationship3Peering Example Computer Communications - CSCI 551 Copyright © William C. ChengISP2 ISP3ISP1Routing TablesPeering Peering4Transit Example Computer Communications - CSCI 551 Copyright © William C. ChengUpstreamTransitProvidor(s)ISP1Transit $$$buying transit is expensiveReduced cost5Why Peer? Computer Communications - CSCI 551 Copyright © William C. Chengreduced number of hopsReduced latencystaff, router cards, etc.Traffic asymmetry (and investment asymmetry)6Why Not Peer? Computer Communications - CSCI 551 Copyright © William C. ChengPotential transit salePeering consumes resourcesmakes a peer into competitionPeering makes a peer ISP appear strongerPeering relations have less contractual teethno incentive to repair problemsPhase 1: Identify peer7Decision Phases Computer Communications - CSCI 551 Copyright © William C. ChengPhase 2: Contact potential peerPhase 3: Agree on peering methodologyTraffic engineering, data collection and analysis8Phase 1: Identify Peer Computer Communications - CSCI 551 Copyright © William C. ChengTechnical, business and legal issuesIntuitionBroader business arrangements (CEO’s play golf together)Peering policies (open, exclusive)open peering policy: we will peer with anyonepolicies are often exposed only under NDAFind the right person!9Phase 2: Contact Peer Computer Communications - CSCI 551 Copyright © William C. ChengSign NDA (optional)Share traffic statisticssplit equallyDirect-circuit v.s. exchange-based interconnection (or acombination)10Phase 3: Peering Methodology Computer Communications - CSCI 551 Copyright © William C. ChengCost sharingI will peer with you if you pay all the costdepends onnumber of peers participating in the regionbandwidth required for the regional interconnections11Value of the Internet Exchange Computer Communications - CSCI 551 Copyright © William C. Cheng# of participantsCostCapacityValue ofExchangeLargeFacilityScalingThe ExchangeStartup HumpCritical Mass Point(value =
View Full Document
Unlocking...