electronic commerce e-business, ninth edition. chapter 2 e-business technology basics e-business,...

Electronic Commerce

E-Business, Ninth Edition

Chapter 2E-Business Technology Basics

E-Business, Ninth Edition

• The origin, growth, and current structure of the

Internet

• How packet-switched networks are combined

to form the internet

• How Internet protocols and Internet

addressing work

• The differences among internets, intranets,

and extranets

• Options for connecting to the Internet,

including cost and bandwidth factors

• Internet2 and the the Semantic Web

Learning Objectives

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4

Two Packet-switched networks

Three Internet protocols

Seven Internet2 and the Semantic

Web

Six Internet connection

options

Five Intranets and extranets

One The Internet and WWW

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Contents

Chapter2 E-Business Technology Basics

Four Markup languages and the Web

The Internet and

2.1The World Wide

Web


2.1 The Internet and the World Wide Web

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2.1.1 Origins of the Internet

2.1.2 New Uses for the Internet

2.1.3 Commercial Use of the Internet

2.1.4 Growth of the Internet

2.1.5 Emergence of the World Wide Web


2.1 The Internet and the World Wide Web

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• Computer network– Any technology allowing people to connect computers to

each other• Internet

• A group of computer networks that have been interconnect .In fact, “internet” is a short for “interconnected network” (small)

• One particular internet, which uses a specific set of rules and connects networks all over the world to each (capital “I”)

• World Wide Web (Web)– Subset of Internet computers on the Internet that are

connected to one another in a specific way that makes them and their contents easily accessible to each other.

– Most important things--Includes easy-to-use interfaces

2.1.1 Origins of the Internet

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• Early 1960s– Defense Department nuclear attack concerns– Used powerful computers (large mainframes)– Used leased telephone company lines

• Single connection– Single connection risk solution

• Communicate using multiple channels (packets)

• 1969 Advanced Research Projects Agency (ARPA)– Packet network connected four computers

• ARPANET: earliest network (became the Internet)• Academic research use (1970s and 1980s)


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• Defense Department network use was original goal– Control weapons systems, transfer research files

• 1970s: other uses– E-mail (1972)– Networking technology

• Remote file transfer and computer access– Mailing lists 邮件名录

• E-mail address forwards message to subscribed users• 1979: Usenet (User’s News Network) 用户新闻组

– Started by a group of students and programmers at Duke University and the University of North Carolina

– Read and post articles– Different topic areas that are called Newsgroups 新闻组


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• Game-playing software created• Limited Internet use

– Research and academic communities• 1979 – 1989

– Network applications improved and tested– Defense Department’s networking software

• Gained wider academic and research institution use• Common communications network benefit recognized

– Security problems recognized• 1980s: personal computer use explosion

– Academic and research networks merged– Companies increasingly used it to construct their own

internal networks

2.1.3 Commercial Use of the Internet

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• National Science Foundation (NSF) 美国科学基金会– The Defense Department network and most of the academic networks

that had teamed up with it were receiving funding from it– The NSF prohibited commercial network traffic on its networks,

• 1989: the NSF permitted two commercial e-mail services– MCI Mail and CompuServe, to establish limited connections to

the Internet for the sole purpose of exchanging e-mail transmissions with users of the Internet.

• 1990s: – people from all walks of life—not just scientists or academic

researchers—started thinking of these networks as the global resource that we now know as the Internet.


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• 1991, the NSF – Further easing of commercial Internet activity restrictions and

began implementing plans to privatize the Internet

• 1995: privatization of the Internet– The NSF Operations turned over to privately owned companies

• Internet based on four network access points (NAPs)

• Network access points (NAPs) 网络访问点– Located in San Francisco, New York, Chicago, and Washington, D. C.– Each operated by a separate telecommunications company – More companies opened, known as network access providers


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• Network access providers 网络访问提供商– Sell Internet access rights directly to larger customers and

indirectly to small firms and individuals through Internet service providers (ISPs)

• Internet service providers (ISPs) 互联网服务商– Sell to smaller firms and individuals

• Internet hosts 互联网主机– Directly connected computers


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• In 40 years, Internet growth– Technological and social accomplishment

– Used by millions of people

– Thousands of different software packages

– Billions of dollars change hands yearly

• The opening of the Internet to business activity helped to dramatically increase its growth; however, there was another development that worked hand in hand with the commercialization of the Internet to spur its growth. The development was the World Wide Web


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• Web (World Wide Web)– As a technological level, the Web is nothing more than

software running on Internet-connected computers– Generates network traffic

• Web software: largest single traffic category• Outpaces: e-mail, file transfers, other data transmission traffic

– New way of thinking about information storage and retrieval

• Key technological Web elements– Hypertext – Graphical user interfaces


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• The Development of Hypertext– 1945: Vannevar Bush: The Atlantic Monthly article

• Visionary ideas about future uses of technology to organize and facilitate efficient access to information. (Memex)

– 1960s: Ted Nelson described hypertext• Hypertext: A similar system in which text on one page link to text

on other pages• Douglas Engelbart created the first experimental hypertext system

– 1989: Tim Berners-Lee (CERN)• Proposed hypertext development project• Provided data-sharing functionality• Developed hypertext server program code


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• Tim Berners-Lee (1955- )– 互联网之父– 1976年毕业于英国牛津大学物理系，获得一级荣誉学位。

– 1984年进入欧洲原子核研究会（ CERN）建立的粒子实验室

– 1989年提出万维网的构想– 1990年开发出第一个网页服务器– 1999年被时代杂志评为 20世纪最重要的 100位人物之一


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• The Development of Hypertext– Hypertext server

• Stores Hypertext Markup Language (HTML) files • Computers connect and read files

– Web server (today)• Hypertext servers used on the Web

– HTML• Developed by Berners-Lee from his original hypertext server program• Set of codes (tags) attached to text• Describes relationships among text elements

– Hypertext link (hyperlink) • Points to another location • Same or another HTML document


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• Graphical Interfaces for Hypertext– Web browser

• A software interface that lets users read (or browse) HTML documents and move from one HTML document to another through text formatted with hypertext link tags in each file

– HTML document• No specification of text element appearance

– A Web browser presents an HTML document in an easy-to-read format in the browser’s graphical user interface (GUI)

• GUI: A way of presenting program control functions and program output to users and accepting their input

• Pictures, icons, and other graphical elements instead of displaying just text


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• The World Wide Web– Berners-Lee called his system of hyperlinked HTML

documents the World Wide Web– Quick acceptance in scientific research community, but few

people outside that community had software that could read the HTML document

– 1993: Marc Andreessen at the University of Illinois wrote Mosaic

• The first GUI program that could read HTML and use HTML hyperlinks to navigate from page to page on computers anywhere on the Internet.

• Mosaic was the first Web browser that became widely available for personal computers, and some Web surfers still use it today


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• The World Wide Web– Easy way to access Internet information

• Provided by functional system of pages connected by hypertext links• Profit-making potential

– 1994: Andreessen and other members of the University of Illinois Mosaic team joined with James Clark of Silicon Graphics to found Netscape Communications

• Its first product, the Netscape Navigator Web browser • Netscape Navigator Web browser program based on Mosaic, was an

instant success• Microsoft: Internet Explorer (most widely used)• Mozilla Firefox: Netscape Navigator descendant

– Number of Web sites• More rapid growth than the Internet itself

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2.2Packet-Switched

Networks


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2.2 Packet-switched Networks


• Local area network (LAN) 局域网– Network of computers located close together

• Wide area networks (WANs) 广域网– Networks of computers connected over greater distances

• The early models (dating back to the 1950s) for WANs were the circuits of the local and long-distance telephone companies of the time, because the first early WANs used leased telephone company lines for their connection

• Circuit 线路– Combination of telephone lines and closed switches connecting

them to each other

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• Circuit switching– Centrally controlled, single-connection model

• Single electrical path between caller and receiver– Works well for telephone calls– Does not work as well for:

• Sending data across large WAN, interconnected network (Internet)

• Circuit-switched network problem– Connected circuit failure

• Causes interrupted connection, data loss

• Solution– Packet switching: move data between two points

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• Packet-switched network– Internet uses packet switching to move data between two

points.• Files and e-mail messages on a packet-switched

network are broken down into small pieces, called packets, that are labeled electronically with their origins, sequences, and destination addresses.

• Packets travel from computer to computer along the interconnected networks until they reach their destinations

• The destination computer collects the packets and reassembles the original file or e-mail message from the pieces in each packet.

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2.2.1 Routing Packets


• Routing computers– Decide how best to forward each packet

• Router computers, routers, gateway computers, border routers– Gateway computers: Gateway from LAN (WAN to the Internet)– Border routers: Between organization and the Internet

• Routing algorithms– Programs on routing computers that determine best path

on which to send each packet contain rules– The programs apply their routing algorithms to information

they have stored in routing tables or configuration tables

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• Routing tables– The information includes lists of connections that lead to

particular groups of other routers, rules that specify which connections to use first, and rules for handling instances of heavy packet traffic and network congestion.

• Variety of rules and standards for creating packets• Hubs 集线器 , switches 交换机 , bridges

– The network devices that move packets from one part of a network to another

• Routers are used to connect network to other networks

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• When packets leave a network to travel on the Internet, they must be translated into a standard format. Routers usually perform this translation function

• Internet routers handle packet traffic along main connecting points– These routers and the telecommunications lines connecting

them are collectively referred to as the Internet backbone

– These routers, sometimes called backbone routers• Three billion packets per second

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FIGURE 2-3 Router-based architecture of the Internet

Internet Protocols

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2.3


2.3 Internet Protocols

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2.3.1 TCP/IP

2.3.2 IP Addressing

2.3.3 Domain Names

2.3.4 Web Page Request and Delivery Protocols

2.3.5 Electronic Mail Protocols

2.3.6 Unsolicited Commercial E-Mail (UCE, Spam)


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• Protocol: collection of network data rules – A collection of rules for formatting, ordering, and error

checking data sent across a network– Includes rules about what is allowed in a transmission and

how it is formatted– Computers must use same protocol

• Proprietary architecture (closed architecture) 专用体系结构– Each computer manufacturer creates own protocol

• Computers made by different manufacturers could not be connected to each other


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• Open architecture– Developed for the evolving ARPANET, which later became

the core of the Internet, included the use of a common protocol for all computers connected to the Internet

– Four key message-handling rules:• Independent networks should not require any internal changes to be

connected to the network• Packets that do not arrive at their destinations must be

retransmitted from their source network• Router computers act as receive-and-forward devices• No global control exists over the network

– has contributed to the success of the Internet because computers manufactured by different companies can be interconnected

2.3.1 TCP/IP

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• The Internet uses two main protocols:– Transmission Control Protocol (TCP) 传输控制协议

• Controls message or file disassembly into packets before Internet transmission

• Controls packet reassembly into original formats at destinations– Internet Protocol (IP) 网络协议

• Specifies addressing details for each packet• Labels packet with origination and destination addresses

• TCP/IP refers to both protocols– Used today (replaced ARPANET NCP)

2.3.2 IP Addressing

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• Internet Protocol version 4 (IPv4)– Used for past 20 years– Uses a 32-bit number to identify computers connected to

the Internet. This address is called an IP address• IP address

– 32-bit number identifying computers• Base 2 (binary) number system

– Computers use for internal calculations– Digit: 0 or a 1 (on or off condition)– Four billion different addresses (232 = 4,294,967,296)

2.3.2 IP Addressing

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• Dotted decimal notation 点分十进制– Four numbers separated by periods

• IP addresses range: 0.0.0.0 to 255.255.255.255

• Byte (8-bit number)– Called an Octet (networking applications)

• Binary values: 00000000 to 11111111• Decimal equivalents: 0 to 255

• Five organizations assign IP addresses

2.3.2 IP Addressing

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• New devices creating high demand for IP addresses• Subnetting 子网技术

– Use reserved private IP LAN (WAN) addresses to provide additional address space

• Private IP addresses 专用 IP地址

– IP numbers not permitted on Internet• Network Address Translation (NAT) device 网络地址转换器– Converts private IP addresses into normal IP addresses

2.3.2 IP Addressing

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• Internet Protocol version 6 (IPv6)– Replaces IPv4 (future)

• Not directly compatible– Advantages

• 128-bit number for addresses• (2128): 34 followed by 37 zeros• Packet format change eliminates unnecessary fields• Adds fields for security, other optional information

– Shorthand notation system for expressing addresses (complex eight groups of 16 bits)

• Group expressed as four hexadecimal digits separated by colons• CD18:0000:0000:AF23:0000:FF9E:61B2:884D

2.3.3 Domain Names

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• Dotted decimal notation difficult to remember• Domain names

– Sets of words assigned to specific IP addresses– Example: www.hebut.edu.cn

• Contains four parts separated by periods• Top-level domain (TLD): rightmost part • Generic top-level domains (gTLDs)• Sponsored top-level domains (sTLD)

– Internet Corporation for Assigned Names and Numbers (ICANN) 互联网域名与地址分配中心

• Responsibility of managing domain names and coordinating them with the IP address registrars.

• Also responsibility of setting standards for the router computers that make up the Internet.

http://www.sandiego.edu/


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• Web client computers– Run software called Web client software (Web browser

software)• Examples: Microsoft Internet Explorer, Google Chrome• Web browser sends Web page file requests to other computers

(Web servers)

• Web server computer– Run software called Web server software

• Receives requests from many different Web clients and respnds by sending files back to those Web client computers.


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Client/server architecture– Combination of client computers running Web client software and

server computers running Web server software

– Web server software receives requests from many different Web clients

– and responds by sending files back to those Web client computers.


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• Hypertext Transfer Protocol (HTTP) 超文本传输协议– The set of rules for delivering Web page files over the Internet– Developed by Tim Berners-Lee in 1991

• Web page request using Web browser– User types protocol name

• Followed by “//:” characters before the domain name• Example: http://www.163.com

– Uniform Resource Locator (URL)统一资源定位符• Combination: protocol name, domain name• Allows a user to locates resources (Web page) on another computer

(Web server)


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• Electronic mail (e-mail)– Sent across the Internet must also be formatted according

to a common set of rules• Most organizations use a client/server structure to

handle e-mail – E-mail server

• Computer devoted to e-mail handling – E-mail client software, such as Microsoft Outlook

• Reads and sends e-mail– An increasing number of people use e-mail services that

are offered by Web sites, such as Hotmail, Gmail• The e-mail servers and clients are operated by the owners of the

Web site


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• With so many different e-mail client and server software choices, standardization and rules are very important– If e-mail messages did not follow standard rules, an e-mail message created by a

person using one e-mail client program could not be read by a person using a different e-mail client program.

• Two common protocols used for sending and retrieving e-mail– Simple Mail Transfer Protocol (SMTP) 简单邮件传输协议

• Specifies mail message format• Describes how mail is to be administered on the e-mail server and

transmitted on the Internet

– Post Office Protocol (POP)邮局协议 can tell the e-mail server• Sends mail to user’s computer, deletes from server• Sends mail to user’s computer, does not delete• Simply Asks if new mail arrived


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• Multipurpose Internet Mail Extensions (MIME) 多用互联网邮件扩展

– Set of rules for handling binary files

• Interactive Mail Access Protocol (IMAP) 交互式邮件访问协议

– Newer e-mail protocol • Same basic POP functions

• Includes additional features

2.3.6 Unsolicited Commercial E-Mail (UCE, Spam)

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• Spam– Also known as:

• Unsolicited commercial e-mail (UCE)• Bulk mail

– Electronic junk mail types• Solicitations, advertisements, or e-mail chain letters

– Wastes people’s time and computer disk space– Consumes large amounts of Internet capacity– Distracts employees

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Markup Language

And The Web

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2.4

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2.4 Markup Language and the Web


2.4.1 Markup Languages

2.4.2 Hypertext Markup Language

2.4.3 Extensible Markup Language (XML)

2.4.4 HTML and XML Editors

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• The most important parts of a Web page are the structure of the page and the text that makes up the main part of the page.– They are stored in a text file that is formatted, or marked up , using a text markup

language

• Text markup language 文本标记语言– Specifies tag set inserted into text

• Markup tags (tags) 标记– Formatting instructions Web client understands

• HTML– Web markup language most commonly used– Standard Generalized Markup Language (SGML) subset

• Older, more complex text markup language• Meta language: used to define other languages

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• Extensible Markup Language (XML) 扩展标准语言– Derived from SGML– Mark up shared information– Meta language

• User creates markup elements extending XML usefulness

• World Wide Web Consortium (W3C)– Not-for-profit group that maintains Web standards

• Extensible Hypertext Markup Language (XHTML)– HTML version 4.0 reformulation as XML application

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2.4.1 Markup Languages


• Generalized Markup Language (GML)– Creates standard electronic document formatting styles

• SGML: version of GML– Adopted by International Organization for Standardization

(ISO)• System of marking up documents • Software application independent• Nonproprietary, platform independent• Offers user-defined tags• Not suited to rapid Web page development, costly to maintain,

requires expensive tools, hard to learn

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2.4.2 Hypertext Markup Languages


• Hypertext elements– Text elements related to each other

• HTML– Prevalent markup language to create Web documents– W3C HTML Working Group page

• Detailed HTML versions, related topic information

• HTML extensions– The process for approval of new HTML features takes a long time,

so Web browser software developers created some features, called HTML extensions, that would only in their browsers

• Draft HTML version 5.0– Includes audio and video features within the markup

language itself

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• HTML tags– Interpreted by Web browser and used by it to format the

display of the text enclosed in angle brackets (<>)• Opening tag and closing tag

– Format text between them• Closing tag

– Preceded by slash within angle brackets (</>)• User may customize tag interpretations• Tags: generally written in lowercase letters

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• One-sided tags– Require opening tag only

• Two-sided tags– Optional closing tag– Closing tag position very important

• Opening tag may contain one or more property modifiers– Further refine tag operation

• Other frequently used HTML tags– Graphics and tables

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• HTML links– Hyperlinks on interlinked pages form a “web” – Can be structured as:– Linear hyperlink structure

• Reads Web page in serial fashion• Works well when customer fills out form

– Hierarchical hyperlink structure• Uses an introductory page (home page, start page) linking to

other pages• Leads customers from general to specific topics

• Hybrid designs combine linear and hierarchical structures

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FIGURE 2-9 Three common Web page organization structures

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• In the late 1990s, companies began turning to XML to help them maintain Web pages that contained large amounts of data

• XML includes data-management capabilities– HTML cannot provide

• XML different from HTML– XML: not a markup language with defined tags, it is a

framework within which individual, companies, and other organizations can create their own sets of tags.

– XML: tags do not specify text appearance on page, the tags convery the meaning (the semantics) of the information included within them

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FIGURE 2-13 Country list data marked up with XML tags as it would appear in Internet Explorer

– Advantages of XML list presentation

• More effectively communicates the meaning of data

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• Strength of XML– Users may define their own tags (weakness as well)

• Solution to user tag definitions– Common XML tags standards

• Data-type definitions (DTDs) or XML schemas– 2001: W3C released set of rules for XML documents– XML vocabulary: set of XML tag definitions

• XML files not intended to display in browser– Extensible Stylesheet Language (XSL)

• Contains formatting instructions– XML parsers: format XML file for device screen

Intranets and Extranets

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2.5


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2.5 Intranets and Extranets


• 2.5.1

• 2.5.2

Public and Private Networks

Virtual Private Network (VPN)


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• Not all TCP/IP networks connect to the Internet• Intranet

– An interconnected network (or internet), usually one that uses the TCP/IP protocol set, and does not extend beyond the organization that created it

• Extranet – An intranet that has been extended to Include specific entities

outside organization boundaries• Although fax, telephone, email, and overnight express carriers have been

the main communications tools for business for many years, extranets can replace many of them at a lower cost

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2.5.1 Public and Private Networks


• Public network– is any computer network or telecommunications network

that is available to the public.– Although a company can operate its extranet using a

public network, very few do because of the high level of security risks.

• Private network – is a private, leased-line connection between two

companies that physically connects their intranets to one another

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2.5.1 Public and Private Networks


• Leased line 专线– a permanent telephone connection between two points.

– A leased line is always active.

– The advantage of a leased line is security.

– Drawback to a private network is cost.

– Scaling problem 伸缩问题 ; is, increasing the number of leased lines in private networks is difficult, costly, and time consuming.

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2.5.2 Virtual Private Network (VPN)


• VPN 虚拟专用网– is an extranet that uses public networks and their protocols to

send sensitive data to partners, customers, suppliers, and employees using a system called IP tunneling or encapsulation.

– IP tunneling IP通道• Effectively creates a private passageway through the public Internet that

provides secure transmission from one computer to another. – Encapsulation 封装

• The virtual passageway is created by VPN software that encrypts the packet content and then places the encrypted packets inside another packet in a process called encapsulation

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2.5.2 Virtual Private Network (VPN)


– VPN software must be installed on the computers at both ends of the transmission.

– Unlike private networks using leased lines, VPNs establish short-term logical connections in real time that are broken once the communication session ends.

– Establishing VPNs does not require leased lines. The only infrastructure required outside each company’s intranet is the Internet

– VPN is an extranet, not every extranet is a VPN.

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Internet Connection Options

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2.6


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2.6 Internet Connection Options



2.6.1 Connectivity Overview

2.6.2 Voice-Grade Telephone Connection

2.6.3 Broadband Connections

2.6.4 Leased-Line Connections

2.6.5 Wireless Connections

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• Internet – Set of interconnected networks

• Organizations connect computers using a network• Internet access providers (IAPs) 互联网接入服务商or ISPs

(Internet service providers) 互联网服务商– Companies provide Internet access to Individuals,

businesses, other organizations– Offer several connection options

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• Common connection options– Voice-grade telephone lines, various types of broadband

connections, leased lines, wireless• Distinguishing factor between various ISPs and their

connection options– Bandwidth

• Amount of data traveling through communication line per unit of time

• Net bandwidth– Actual speed information travels– Traffic on the Internet and at your local service provider

greatly affects net bandwidth

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• Connection type– Symmetric connections 对称接入

• Provide same bandwidth in both directions

– Asymmetric connections 非对称接入• Provide different bandwidths for each direction

• Two bandwidth types in asymmetric connection– Upstream bandwidth (upload bandwidth)

• Amount of information from user to the Internet in a given amount of time

– Downstream bandwidth (download, downlink bandwidth)• Amount of information from the Internet to user in a given amount of

time

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2.6.2 Voice-Grade Telephone Connections



• Local telephone service provider– Most common way for an individual to connect to ISP

• Plain old telephone service (POTS) 传统电话服务– Uses existing telephone lines and analog modem

• Bandwidth between 28 and 56 Kbps

• Digital Subscriber Line (DSL) 数字用户线路 protocol– Higher grade of service– Use DSL modem (type of network switch)

• Integrated Services Digital Network (ISDN) 综合业务数字网– First technology developed using DSL protocol suite

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• Broadband Connection speeds greater than 200 Kbps– Asymmetric digital subscriber line (ADSL) 非对称数字用户服务

• One of the newest technologies that uses the DSL protocol to provide service

• Transmission bandwidth is 100~640kbps upstream and 1.5~9Mbps downstream

– High-speed DSL (HDSL)• More than 768 Kbps symmetric bandwidth

– Cable modems 线缆调制解调器• Connected to the same broadband coaxial cable that serves a television• Transmission speeds: 300 Kbps to 1 Mbps

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• Voice-grade lines– The telephone lines used to cover the vast distances between

rural customers

– Cost less than telephone lines designed to carry data

– Usually less than 14 Kbps bandwidth

• Data-grade lines– Wired most urban and suburban areas

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2.6.4 Leased-Line Connections



• More expensive technologies– Classified by equivalent number of telephone lines included

• DS0 (digital signal zero)– The telephone line designed to carry one digital signal (56 Kbps)

• T1 line (DS1)– Carries 24 DS0 lines (1.544 Mbps)

• Fractional T1– 128 Kbps and upward in 128-Kbps increments

• T3 service (DS3): 44.736 Mbps

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• Satellite microwave transmissions– Download speeds of 500 Kbps– Upload handled by POTS modem connection

• Today: POTS modem connection not required– Use microwave transmitter for uploads (150 Kbps)– Costs and accuracy improving

• Many wireless network types now available– Internet-capable mobile phones, smart phones, game

consoles, and notebook computers– More than half of U.S. Internet users used a wireless

device for Internet access

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• Bluetooth 蓝牙– Design for personal use over short distances– Low-bandwidth technology (up to 722 Kbps)– Personal area networks (PANs) or piconets 微微网– Advantages:

• Devices consume very little power (important for mobile devises)• Devices can discover one another and exchange information

automatically

• Ultra Wideband (UWB) 超宽带– Provides bandwidth up to 480 Mbps– Connections over short distances (30 to 100 feet)– Future personal area networking applications

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• Wireless Ethernet (Wi-Fi)– Wi-Fi (wireless Ethernet, 802.11b)– The most common wireless connection technology for use on LANs– Wireless access point (WAP) 无线访问点

• Device that transmits packets between Wi-Fi-equipped computers and other devices within range

– 802.11b (11 Mbps): range of about 300 feet– 802.11a (54 Mbps): not 802.11b compatible– 802.11g (54 Mbps): 802.11b compatible– 802.11n: “Draft-N” (300 to 450 Mbps range)

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• Wireless Ethernet (Wi-Fi) – Wi-Fi devices are capable of roaming 漫游

• Shifting from one WAP to another• Without requiring intervention by the user

– Hot spots 无线热点• WAPs open to public

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• Cellular telephone networks– Broadcast signals to (receive signals from) antennas

• Three miles apart in grid– Original design: voice communications– Third-generation (3G) cell phones

• Combine latest technologies available today– Short message service (SMS) protocol

• Send and receive short text messages– Mobile commerce or m-commerce

• Describes resources people might want to access (and pay for) using wireless devices

82

the Semantic Web

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2.7


Internet2 and

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2.7 Internet2 and the Semantic Web

2.7 Internet2 and the Semantic Web

• Internet2– Experimental networking technologies test bed– Has achieved bandwidths of 10 Gbps and more on parts of

its network– Used by universities, medical schools, CERN

• Semantic Web 语义网project (next-generation Web)– Goal: blending technologies and information into a next-

generation Web • Tim Berners-Lee began• Have words on Web pages tagged (using XML) with their meaning


Summary


• Early development of Internet technology began in the 1960s through research projects– Commercial use began with e-mail– Privatization of the Internet completed in 1995

• Packet-switched networks form the Internet– Uses routing, IP addressing

• Technologies supporting the Internet, Web, and electronic commerce– Protocols, programs, languages, architectures– TCP/IP– HTML, SGML, XML

Summary


• HTML defines structure and content of Web pages• Extensible Markup Language (XML)

– Uses markup tags to describe the meaning or semantics of text

• Networking technologies– Internets, intranets, extranets– Extranet types

• Public network, private network, virtual private network

Summary


• Internet service provider connection types– Basic telephone connections, broadband cable, satellite

microwave transmission, DSL, wireless (fixed-point, mobile)

• Internet2 experimental test bed – Creating, perfecting future high-speed networking

technologies• Semantic Web project

– Goal of making research data widely available– May enable Web interaction using intelligent software

agents

Chapter 2


electronic commerce e-business, ninth edition. chapter 2 e-business technology basics e-business,...

Documents

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internethow internet

world wide web2

electronic commerceebusiness

earliest network

new uses

internetacademic research

transfer research files1970s