PSTN Data PresentationPSTN Economic Regulation (US)Technology – Copper to FiberData Collection and ChallengesMini Bell NetworkNano Bell Data DescriptionsNano Bell: 2010 Network AnalysisNext Steps© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology1PSTN Data PresentationBy Jijun LinDan LivengoodChintan VaishnavFaculty Advisor: Dan WhitneyESD 342, Advanced Systems Architecture© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology2PSTN Economic Regulation (US)1934-1984(national)1984-1996(each region)After 1996(each state)AT&TAT&TMCISprintRegionalBells(Nine Total One perRegion)AT&TMCISprintILECCLECCLECCLECOur analysis focuses on an ILEC and a CLEC for a single stateMaxi BellMini BellNano BellFigure by MIT OCW.International gateway exchange (Centre de Transit 3)National tandem exchanges(Tertiary trunk switching centers)Regional tandem exchanges(Secondary trunk switching centers)Local tandem exchanges(Primary trunk switching centers)Local exchangesSubscriber linesSatellite linksSubmarinecablesInternationalnetworkTrunk networkLocalnetwork© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology3Technology – Copper to FiberCopperFiberFiber has statistical aggregation similar to old PSTN, but with better SN ratio. Fiber rings have specific robustness features.Figure by MIT OCWFigure by MIT OCWInternational gateway exchange (Centre de Transit 3)National tandem exchanges(Tertiary trunk switching centers)Regional tandem exchanges(Secondary trunk switching centers)Local tandem exchanges(Primary trunk switching centers)Local exchangesSubscriber linesSatellite linksSubmarinecablesInternationalnetworkTrunk networkLocalnetworkInternational gateway exchange (Centre de Transit 3)National tandem exchanges(Tertiary trunk switching centers)Regional tandem exchanges(Secondary trunk switching centers)Local tandem exchanges(Primary trunk switching centers)Local exchangesSubscriber linesSatellite linksSubmarinecablesInternationalnetworkTrunk networkLocalnetwork© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology4Data Collection and Challenges• Maxi Bell and Other Sensitive Data (we cannot get this data)– Call Routing Information – efficient Interstate and Intrastate call routing provides competitive advantage– Class 1, 2 and 3 switches -- national security concerns, blurring boundaries between regional and long-distance– Customer base – Competitive and privacy concerns• Mini Bell (we have data)– Tandem (Class 4) and the sub-tending CO (Class 5) switches• Nano Bell (we have data)– 2005 (Current) and 2010 (Planned) CLEC Network maps with connectivity informationModeling the combination of a Nano Bell network and its connectivity toMini Bell allows us to analyze most inter and intrastate call scenarios.Image removed for copyright reasons.© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology5Mini Bell NetworkTandem: 25 • Three type of Tandem:– ACCESS–LOCAL– E911• All tandems are connected each other• 7 of them directly connect to central offices• One tandem is out of state (node 165)Central Office: 146• Each central office only directly connect to one tandemSome Metrics:• n = 171• m = 892• Mean degree: z = 5.216• Cluster coefficient: C = 0.807© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology6Nano Bell Data Descriptions• Nodes– Black dots: host locations that are actively involved in the larger switching network– Red dots: remote locations where calls originate and terminate• Links– Copper or fiber wires• Rings– Connect host locations via high bandwidth fiber– Represented by various thick colored lines– 2005: 6 rings connecting approximately 1/3 of host locations– 2010: 18 rings roughly connecting all host locations• Structural Changes2005: 2010:Image removed for copyright reasons.Image removed for copyright reasons. Image removed for copyright reasons.© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology7Nano Bell: 2010 Network Analysis• Basic metrics– Number of host nodes: n = 123• 4 tandem switches– Number of links: m = 296– Mean degree: z = 2.047– Cluster coefficient: C = 0.032• Betweenness (node centrality)– When ranked, 3 of the top 4 nodes in betweenness are tandem switches (4thof top 4 is adjacent to the tandem switch with highest betweenness)– Last tandem switch is ranked #12Images removed for copyright reasons.© 2006 Student: Jijun Lin, Daniel Livengood, Chintan Vaishnav, Engineering Systems Division, Massachusetts Institute of Technology8Next Steps• Connect Nano Bell to Mini Bell for larger network analysis• Further analysis of each network individually• Network analysis comparison of 2005 and 2010 Nano Bell structures• Analysis of ‘illities’– Survivability (Robustness) - Collapsed vs. physically separated SONET rings (bulldozer proofing the network)– Availability - Node capacity and link bandwidth (transition to
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