Business Data Communications and Networking - Chapter 10: The Internet

Business Data Communications and Networking 8th Edition Jerry Fitzgerald and Alan DennisJohn Wiley & Sons, Inc Prof. M. UlemaManhattan CollegeComputer Information Systems1Copyright 2005 John Wiley & Sons, IncChapter 10The Internet2Copyright 2005 John Wiley & Sons, IncOutlineHow Internet worksArchitectureInternet Access TechnologiesDSL and cable modemWireless AccessInternet GovernanceInternet 23Copyright 2005 John Wiley & Sons, IncInternetMost used network in the worldNot one network, but a network of networksMade up of thousands of networks of National and state government agencies, Non-profit organizations and for-profit companies.A rigidly controlled club To exchange data, these networks must agree to use Internet protocolsTCP/IP MUST be supported by all networks Unrestricted applications and contentsDeveloped freely4Copyright 2005 John Wiley & Sons, IncInternet’s Hierarchical StructureNational Internet Service Providers (ISPs)Provide services to their customers and sell access to regional ISPs and local ISPsRegional ISPsConnect with National ISPsProvide services to their customers and sell access to local ISPsLocal ISPs Connected to National or Regional ISPsSell access to individuals5Copyright 2005 John Wiley & Sons, IncInternet’s Access PointsNetwork Access Points (NAPs)Connect National ISPs togetherSometimes large regional and local ISPs also have access directly to NAPsIndiana University, for example, which provides services to about 40,000 individuals, connects directly to the Chicago NAPAbout a dozen NAPs in the U.S.Run by common carriers such as Sprint and AT&TMetropolitan Area Exchanges (MAEs)Connect Regional ISPs togetherAbout 50 such MAEs in the U.S. today6Copyright 2005 John Wiley & Sons, IncBasic Internet Architecture7Copyright 2005 John Wiley & Sons, IncPacket Exchange ChargesPeeringISPs at the same level usually do not charge each other for exchanging messagesHigher level ISPs charge lower level onesNational ISPs charge regional ISPs which in turn charge local ISPsLocal ISPs charge individuals and corporate users for access8Copyright 2005 John Wiley & Sons, IncConnecting to an ISPDone by through ISP’s Point of Presence (POP)A place ISP provides service to its customersIndividual users Typically through a dial-up line using the PPP protocolHandled by the ISP’s modem poolUserid and password checked by Remote Access Server (RAS) Once logged in, the user can send packets over the phone lineCorporate users Typically access the POP using a T-1, T-3 or ATM OC-3 connections provided by a common carrierCost = ISP charges + circuit charges9Copyright 2005 John Wiley & Sons, IncISP Point-of PresenceModem PoolIndividual Dial-up CustomersCorporate T1 CustomerT1 CSU/DSUCorporate T3 CustomerT3 CSU/DSUCorporate OC-3 CustomerATM SwitchLayer-2 SwitchISP POPISP POPISP POPNAP/MAERemoteAccess ServerATM SwitchInside an ISP POP10Copyright 2005 John Wiley & Sons, IncATM SwitchRouteServerRouterISP ARouterISP BRouterISP CRouterISP DISP EATM SwitchISP FATM SwitchInside an Internet NAP (Chicago)One of the busiest (4 Gbps; 140 ISPs)Used to exchange routing information through BGP11Copyright 2005 John Wiley & Sons, IncInternet Backbones in 2002Backbone circuits for national ISPsOC-48 and OC-192 (10 Gbps) becoming commonTo be converted to OC-192 (10 Gbps) by 2005OC-768 (40 Gbps) and use OC-3072 (160 Gbps) in experiment stageAggregate Internet trafficGrowing rapidlyExpected to reach 40 Terabits per second (Tbps) by 2007.NAPs and MAEs becoming bottlenecksRequiring larger and larger switches12Copyright 2005 John Wiley & Sons, IncSprint’s Internet BackboneA national ISP in North AmericaCircuits: mostly ATM OC-12; few OC-48 and OC-192>>>> Fig 10.4 goes here13Copyright 2005 John Wiley & Sons, IncInternet Access TechnologiesMost commonly used56K dial-up lines (individuals)T1 or T3 lines into ISPs (organizations) New access technologiesCommonly called “broadband access”Provide higher speed accessDigital Subscriber Line (DSL)Cable ModemsFixed Wireless (including satellite access)Mobile Wireless (WAP)14Copyright 2005 John Wiley & Sons, IncDigital Subscriber Line (DSL)A family of point-to-point technologiesDesigned to provide high speed data transmission over traditional telephone linesTraditional telephone lines (local loop) Limited capacity due to telephone and switching equipment at the end officesConstrained by 4 KHz voice channelMuch higher bandwidth possible (with new technology based equipment  DSL)Requires changing telephone equipment; not rewiring the local loopNot available in all locations in the USMore wide spread in Asia, Europe and Canada15Copyright 2005 John Wiley & Sons, IncLocal Carrier End OfficeLine SplitterCustomer PremisesTelephoneDSL Modem Hub Computer Computer Local LoopMainDistributionFrameCustomerPremisesCustomerPremisesVoice Telephone NetworkDSL AccessMultiplexerATM SwitchISP POPISP POPISP POPISP POPDSL Architecture16Copyright 2005 John Wiley & Sons, IncTypes of DSLAsymmetric DSL (ADSL)Uses three FDM channels4 KHz analog voice channelA simplex data channel for downstream trafficA slower full-duplex data channel for Upstream traffic Size of digital channelsDepends on the distance (CPE-Office) (up to 18,000 ft)Most common (T1): 1.5 Mbps down; 384 Kbps upVery high data rate DSL (VDSL)Designed for local loops of 4500 ft or less (1000 ft ideal)Also uses three FDM channels as in ADSLSize of digital channels (distance sensitive)Most common (1/4OC1): 12 Mbps down; 1.6 Mbps up17Copyright 2005 John Wiley & Sons, Inc TypeMaximum Lengthof Local LoopMaximumDownstream RateMaximum Upstream RateT118,000 feet1.5 Mbps384 KbpsE1*16,000 feet2.0 Mbps384 KbpsT212,000 feet6.1 Mbps384 KbpsE2*9,000 feet8.4 Mbps640 Kbps * E1 and E2 are the European standard services similar to T1 and T2 services in North AmericaADSL Data Rates18Copyright 2005 John Wiley & Sons, Inc >>>>>> Fig 10.7 goes hereVDSL Data Rates19Copyright 2005 John Wiley & Sons, IncCable ModemsA digital service offered by cable television companiesData Over Cable Service Interface Specifications (DOCSIS)Most common protocol used for cable modemsNot a formal standardOffers vary (depends on the quality of cable plant)In theory: downstream: 27-55Mbps; upstream: 2-10 MpbsTypical: downstream: 1.5 -2 Mbps; upstream 0.2 – 2 Mbps A few cable companies offer downstream services onlyUpstream communications using regular telephone lines20Copyright 2005 John Wiley & Sons, IncCable Modem ArchitectureSimilar to DSL (with one main difference):DSL: point-to-point technologyCable modems: use shared multipoint circuitsAll messages on the circuit heard by all computers on the circuit  security issue300 – 1000 customers per cable segmentType of equipment usedCable Modem Termination System (CMTS)Used for upstream traffic onlyConverts data from DOCSIS to Internet protocolsFiber Node with an Optical Electrical (OE) converterCombiner (for downstream traffic only)Combines Internet traffic with TV video traffic21Copyright 2005 John Wiley & Sons, IncCable Company Distribution HubCable SplitterCustomer PremisesTVCable Modem Hub Computer Computer SharedCoaxCableSystemCombinerCustomerPremisesCustomerPremisesTV VideoNetworkCable ModemTerminationSystemISP POPCable CompanyFiber NodeOptical/ElectricalConverterDownstreamUpstreamRouterCable CompanyFiber NodeBasic Cable Modem Architecture22Copyright 2005 John Wiley & Sons, IncFixed WirelessRequires “line of sight” access between transmittersRequires tall buildings and towersCommon use: provide Internet access to multi-tenant buildings (apartment buildings, hotels, etc.,)Types of FWAPoint-to-point typesUsed to connect only two locationsPoint-multipoint typesAllow access by a limited number of stationsDesigned as an alternative to DSL, cable modemsData access speeds Range from 1.5 to 11 Mbps23Copyright 2005 John Wiley & Sons, IncFixed Wireless>>>Fig 10.10 goes here24Copyright 2005 John Wiley & Sons, IncMobile WirelessAllows users to access the Internet from any locationNext major challenge in networking: Widespread mobile high speed Internet accessCurrent Mobile wireless technologiesSlow access speeds compared to DSL,cable modemWLAN: Higher speed, but limited range and locationsWireless Application Protocol (WAP)Based on Wireless Application Environment (WAE) and Wireless Markup Language (WML)Streamlines HTTP and HTML for use in the very limited low speed and small screens of mobile devices25Copyright 2005 John Wiley & Sons, IncWAP Architecture>>>>>>> Fig 10.10 goes here26Copyright 2005 John Wiley & Sons, IncFuture Access TechnologiesPassive Optical Networking (PON) Also called Fiber to the HomePotential of optical fiber communications to end users Possibility of thousands of channels (with WDM)Doesn’t require electricity, thus “passive”Limits its maximum distance (about 10 miles)No standards yetEthernet to the Home Yipes.com is now doing this in several large US citiesGives home users 10BaseT or 100BaseT connectionsA TCP/IP router installed into the customer’s network connect to an Ethernet MANNo protocol conversion required27Copyright 2005 John Wiley & Sons, IncInternet GovernanceNo one operates the InternetClosest thing: Internet Society (ISOC)Open membership professional societyOver 175 organizational and 8000 individual members in over 100 countriesMission: “Open development, evolution and use of the Internet for the benefit of the people in the world.”ISOC work areasPublic policy:Involves in debates in copyright, censorship, privacyEducationTraining and education programsStandards28Copyright 2005 John Wiley & Sons, IncISOC Standard BodiesInternet Engineering Task Force (IETF)Concerned with evolution of Internet architecture and smooth operation of InternetWork through groups (organized by topics)Request For Comments (RFC): basis of Internet standardsInternet Engineering Steering Group (IESG)Responsible for management of the standard processEstablishes and administers rules in creating standardsInternet Architecture Board (IAB)Provides strategic architectural oversight, guidanceInternet Research Task Force (IRTF)Focus on long-term specific issues29Copyright 2005 John Wiley & Sons, IncInternet 2Many new projects designing new technologies to evolve InternetPrimary North American projectsNext Generation Internet (NGI) funded by NSFDeveloped very high performance Backbone Network Service (vBNS)Run by WorldComUniversity Corporation for Advanced Internet Development (UCAID) with 34 universitiesDeveloped Abilene network (also called Internet 2)Advanced Research and Development Network Operations Center (ARDNOC) funded by Canadian governmentDeveloped CA*Net30Copyright 2005 John Wiley & Sons, IncBackbone for Internet 2>>>>> Fig 10.11 goes here31Copyright 2005 John Wiley & Sons, IncFeatures of Future InternetAccess via Gigapops, similar to NAPsOperate at very high speeds (622 Mbps to 2.4 Gbps) using SONET, ATM and IPv6 protocolsIPv6 not IPv4New protocol development focuses on issues like Quality of Service MulticastingNew applications includeTele-immersion Videoconferencing32Copyright 2005 John Wiley & Sons, IncImplications for ManagementConcern about traffic slowing down InternetNew fiber based circuits deployment  overbuiltMany new broadband technologies for high speed Internet accessSimple to move large amount of data into most homes and business  richer multimedia appsWhich access technology to dominate?Challenge: Figure out which one33Copyright 2005 John Wiley & Sons, IncCopyright 2005 John Wiley & Sons, Inc. 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