Thương mại điện tử - The Internet and The Web - Chapter-2 - Part 2

CSC 330 E-CommerceTeacher Ahmed Mumtaz Mustehsan GM-IT CIIT Islamabad Virtual Campus, CIIT COMSATS Institute of Information TechnologyT1-Lecture-4The Internet and The WebChapter-2Part-IIT1-Lecture-4For Lecture Material/Slides Thanks to: Copyright © 2010 Pearson Education, IncObjectivesExplain the current structure of Internet.Understand the limitations of todays internetDescribe the potential capabilities of Internet IIUnderstand how the world wide web worksDescribe how internet and web features and services support e-commerce.T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-3The Hourglass Model of the InternetSOURCE: Adapted from Computer Science and Telecommunications Board (CSTB), 2000.T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-4The Hourglass Model of the InternetT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-5The Internet can be characterized as an hour-glass modular structure with a lower layer containing the bit-carrying infrastructure (including cables and switches) and an upper layer containing user applications such as e-mail and the Web. In the narrow waist are transportation protocols such as TCP/IP.Network Technology Substrate layerLayer-1 of Internet technology that is composed of telecommunications networks and protocolsTransport Services and Representation Standards layerLayer-2 of Internet architecture that houses the TCP/IP protocolThe Hourglass Model of the InternetT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-6Middleware Services layerLayer-3: The “glue” that ties the applications to the communications networks, and includes such services as security, authentication, addresses, and storage repositories.Applications layerLayer-4 of Internet architecture that contains client applications; such as World Wide Web, e-mail, and audio or video playback.Internet Network ArchitectureT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-7Metropolitan Area Exchanges (MAEs),Network Access Points (NAPs)Internet Network Architecture ConceptsBackbone: High-bandwidth fiber-optic cable networks Private networks owned by a variety of Network Service Providers (NSPs).Bandwidth: 155 Mbps 2.5 GbpsBuilt-in redundancyNetwork Service Provider (NSP)Owns and controls one of the major networks comprising the Internet’s backboneBandwidthmeasures how much data can be transferred over a communications medium within a fixed period of time; is usually expressed in bits per second (bps), kilobits per second (Kbps), megabits per second (Mbps),or gigabits per second (Gbps)RedundancyMultiple duplicate devices and paths in a networkT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-8Internet Exchange Points (IXPs). Hubs where backbones intersect with regional and local networks, and backbone owners connect with one another (older term NAPS)Campus area networks (CANs)LANs operating within a single organization that leases Internet access directly from regional or national carrier. such as New York University or Microsoft CorporationT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-9Internet Network Architecture ConceptsInternet Service Providers (ISPs)Provide lowest level of service to individuals, small businesses, some institutionsNarrowbandthe traditional telephone modem connection, now operating at 56.6 Kbpsbroadbandrefers to any communication technology that permits clients to play streaming audio and video files at acceptable speed generally anything above 100 Kbps.Digital Subscriber Line (DSL)a telephone technology for delivering high-speed access through ordinary telephone lines found in homes or businessesT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-10Internet Network Architecture ConceptsCable modemA cable television technology that piggybacks digital access to the Internet on top of the analog video cable providing television signals to a homeT1 Line an international telephone standard for digital communication that offers guaranteed delivery at 1.54 MbpsT3 an international telephone standard for digital communication that offers guaranteed delivery at 45 MbpsSatellitebulk transfers at variable rates (250 Kbps–1 Mbps)T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-11Internet Network Architecture ConceptsIntranets and ExtranetsIntranet (Internal network)A TCP/IP network located within a single organization for purposes of communications and information processing. e.g. Intranet of CIITExtranet (external network)Formed when firms permit outsiders to access their internal TCP/IP networks. e.g. General Motors permits parts suppliers to gain access to GM’s intranetNote: Intranets and extranets generally do not involve commercial transactions in a marketplace, however, extranets supports certain types of B2B exchangesT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-12Who Governs the Internet?Promoters of internet claim that no one governs internet as it is public domain and inherently above and beyond the law. However, there are certain organization that influence Internet and monitor its operations such as : Internet Architecture Board (IAB)Internet Corporation for Assigned Names and Numbers (ICANN)Internet Engineering Steering Group (IESG)Internet Engineering Task Force (IETF)Internet Society (ISOC)World Wide Web Consortium (W3C)International Telecommunications Union (ITU)T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-13Limitations of current Internet InfrastructureBandwidth limitations: Backbone, MAN,CAN & last-mileQuality of service limitationsLatency : delays in messages caused by the uneven flow of information packets through the network.“best-effort” quality of service (QoS), which makes no guarantees about when or whether data will be delivered,Network architecture limitationsDownloading same music by thousands of clients slows down network performance as the same music track is sent out a thousand times to clients that might be located in the same metropolitan areaLanguage development limitationsHTML, the language of Web pages, is fine for text and simple graphics, but poor at defining and communicating “rich documents,” such as databases, business documents, or graphics.Wired Internet limitationsCopper cables use a old technology, and fiber-optic cable is expensive to place underground. The wired nature of the Internet restricts mobility of users as compared to wifi.T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-14The Internet2® ProjectConsortium of 200+ universities, government agencies, and private businesses collaborating to find ways to make the Internet more efficient, faster, reliable and affordable.GigaPoP : a regional Gigabit Point of Presence, or point of access to the Internet2 network, that supports at least one gigabit (1 billion bits) per second information transferPrimary goals:Create leading edge very-high speed network for national research communityEnable revolutionary Internet applicationsEnsure rapid transfer of new network services and applications to broader Internet community T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-15The Larger Internet II Technology Environment: GENI InitiativeGlobal Environment for Networking Innovations (GENI) Initiative to develop new core functionality for the Internet, including new naming, addressing and identity architectures; enhanced capabilities, including additional security architecture and a design that supports high availability; new Internet services and applicationsProposed by NSF to develop new core functionality for InternetMost significant private initiatives (Fiber-Optic and Wireless)Fiber optics is concerned with the first mile or backbone Internet services that carry bulk traffic long distances. Wireless Internet is concerned with the last mile from the larger Internet to the user’s cell phone or laptop. Mobile wireless Internet servicesT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-16Fiber Optics and the Bandwidth Explosion in the First Mile“First mile”: Backbone Internet services that carry bulk traffic over long distancesOlder transmission lines being replaced with fiber-optic cable Much of fiber-optic cable laid in United States is “dark”, but represents a vast digital highway that can be utilized in the futurePhotonic technologies expand capacity of existing fiber linesT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-17Optical FiberT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-18Optical FiberSource: Adapted from Panko, Raymond, Business Data Communications and Networking (3rd ed.), Upper Saddle River, NJ: Prentice-Hall, 2001, p. 278.T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-19Mobile Wireless Internet Access: The Last Mile: “Last mile”: From Internet backbone to user’s computer, cell phone, PDA, etc. Two different basic types of wireless Internet access:Telephone-based (mobile phones, smartphones)Computer network-basedT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-20Telephone-based Wireless Internet AccessEvolution:(1-G) The first generation of cellular networks were analog-based.(2G) Second generation cellular networksRelatively slow circuit-switched digital network that can transmit data at about 10 Kbps(2.5G) network interim cellular networkthat provides speeds of 60–144 Kbps using General Packet Radio Services (GPRS)GPRS (General Packet Radio Services) : next generation technology carries data in packets, just like the Internet, but over radio frequencies that make wireless communication possible.(3G) Third generation cellular network new generation of cellular phone standards that can connect users to the Web at 2.4 MbpsT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-21Telephone-based Wireless Internet AccessCompeting 3G standardsGSM (Global System for Mobile Communications) mobile communications system widely used in Europe and Asia that uses narrowband Time Division Multiple Access (TDMA)CDMA (Code Division Multiple Access) mobile communications system widely used in the United States that uses the full spectrum of radio frequencies and digitally encrypts each call(4 G) Fourth Generation: (LTE and WiMax )Long Term Evolution: True broadband cell phone provides up to 100 - 300 MbpsWiMaxAlternative to LTE wide area network for cities provides 72 Mbps.T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-22Wireless Local Area Networks (WLANs)Wi-FiHigh-speed, fixed broadband wireless LAN, different versions for home and business market, limited range.WiMaxHigh-speed, medium range broadband wireless metropolitan area network.BluetoothLow-speed, short range connection.Ultra-Wideband (UWB)Low power, short-range high bandwidth network.ZigbeeShort-range, low-power wireless network technology for remotely controlling digital devices.T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-23Wi-Fi NetworksT1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc1-24