Ahmed Mumtaz Mustehsan CSC 330 E-Commerce Teacher Ahmed Mumtaz Mustehsan GM-IT CIIT Islamabad Virtual Campus, CIIT COMSATS Institute of Information Technology T1-Lecture-4

The Internet and The Web Chapter-2 Part-II T1-Lecture-4 For Lecture Material/Slides Thanks to: Copyright © 2010 Pearson Education, Inc

Objectives Explain the current structure of Internet. Understand the limitations of todays internet Describe the potential capabilities of Internet II Understand how the world wide web works Describe how internet and web features and services support e-commerce. T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

The Hourglass Model of the Internet SOURCE: Adapted from Computer Science and Telecommunications Board (CSTB), 2000. T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

The Hourglass Model of the Internet The 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 layer Layer-1 of Internet technology that is composed of telecommunications networks and protocols Transport Services and Representation Standards layer Layer-2 of Internet architecture that houses the TCP/IP protocol T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

The Hourglass Model of the Internet Middleware Services layer Layer-3: The “glue” that ties the applications to the communications networks, and includes such services as security, authentication, addresses, and storage repositories. Applications layer Layer-4 of Internet architecture that contains client applications; such as World Wide Web, e-mail, and audio or video playback. T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Internet Network Architecture Metropolitan Area Exchanges (MAEs), Network Access Points (NAPs) T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Internet Network Architecture Concepts Backbone: High-bandwidth fiber-optic cable networks Private networks owned by a variety of Network Service Providers (NSPs). Bandwidth: 155 Mbps 2.5 Gbps Built-in redundancy Network Service Provider (NSP) Owns and controls one of the major networks comprising the Internet’s backbone Bandwidth measures 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) Redundancy Multiple duplicate devices and paths in a network T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Internet Network Architecture Concepts Internet 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 Corporation T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Internet Network Architecture Concepts Internet Service Providers (ISPs) Provide lowest level of service to individuals, small businesses, some institutions Narrowband the traditional telephone modem connection, now operating at 56.6 Kbps broadband refers 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 businesses T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Internet Network Architecture Concepts Cable modem A cable television technology that piggybacks digital access to the Internet on top of the analog video cable providing television signals to a home T1 Line an international telephone standard for digital communication that offers guaranteed delivery at 1.54 Mbps T3 an international telephone standard for digital communication that offers guaranteed delivery at 45 Mbps Satellite bulk transfers at variable rates (250 Kbps–1 Mbps) T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Intranets and Extranets Intranet (Internal network) A TCP/IP network located within a single organization for purposes of communications and information processing. e.g. Intranet of CIIT Extranet (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 intranet Note: Intranets and extranets generally do not involve commercial transactions in a marketplace, however, extranets supports certain types of B2B exchanges T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Who 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, Inc

Limitations of current Internet Infrastructure Bandwidth limitations: Backbone, MAN,CAN & last-mile Quality of service limitations Latency : 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 limitations Downloading 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 area Language development limitations HTML, 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 limitations Copper 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, Inc

The Internet2® Project Consortium 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 transfer Primary goals: Create leading edge very-high speed network for national research community Enable revolutionary Internet applications Ensure rapid transfer of new network services and applications to broader Internet community T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

The Larger Internet II Technology Environment: GENI Initiative Global 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 applications Proposed by NSF to develop new core functionality for Internet Most 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 services T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Fiber Optics and the Bandwidth Explosion in the First Mile Backbone Internet services that carry bulk traffic over long distances Older 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 future Photonic technologies expand capacity of existing fiber lines T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Optical Fiber T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Optical Fiber Source: 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, Inc

Mobile Wireless Internet Access: The 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-based T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Telephone-based Wireless Internet Access Evolution: (1-G) The first generation of cellular networks were analog-based. (2G) Second generation cellular networks Relatively slow circuit-switched digital network that can transmit data at about 10 Kbps (2.5G) network interim cellular network that 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 Mbps T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Telephone-based Wireless Internet Access Competing 3G standards GSM (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 Mbps WiMax Alternative to LTE wide area network for cities provides 72 Mbps. T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Wireless Local Area Networks (WLANs) Wi-Fi High-speed, fixed broadband wireless LAN, different versions for home and business market, limited range. WiMax High-speed, medium range broadband wireless metropolitan area network. Bluetooth Low-speed, short range connection. Ultra-Wideband (UWB) Low power, short-range high bandwidth network. Zigbee Short-range, low-power wireless network technology for remotely controlling digital devices. T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc

Wi-Fi Networks T1-Lecture-4 Ahmed Mumtaz Mustehsan Copyright © 2010 Pearson Education, Inc