Electronic commerce fundamentals ch2

Chapter 2 The Internet and the Web: Infrastructure for Electronic Commerce Electronic Commerce Objectives General structure of the network of networks supporting the Internet and ecommerce ◆ Protocols that move commerce across the Internet and send/receive e-mail ◆ Internet utility programs to trace, locate, and verify the status of Internet host sites ◆ 2 Objectives Popular Internet applications, including e-mail, Telnet, and FTP ◆ History and use of Web markup languages, including SGML, HTML, and XML ◆ HTML tags and links ◆ Web client and server architectures and the messages they send to each other ◆ Objectives Differences and similarities between internets, intranets, and extranets ◆ Options for connecting to the Internet, their cost and bandwidth tradeoffs ◆ Technology Overview Internet is the most obvious technology needed to conduct e-commerce ◆ Other technologies are also required ◆ ● Database software ● Network switches and hubs ● Encryption hardware and software ● Multimedia support ◆ Potential for business volume to double in less than a year Packet-Switched Networks Local and long distance telephone companies were early models in the 1950s ◆ Single paths were created to connect two parties together, called circuit switching ◆ Packet-Switched Networks ◆ The Internet uses Packet switching ● Files and messages are broken down into packets, which are electronically labeled with their origin and destination ● The destination computer collects the packets and reassembles the data from the pieces in each packet ● Each computer the packet encounters decides the best route towards its destination Packet-Switched Network and Message Packets Figure 2-1 Open Architecture Independent networks should not require any internal changes in order to be connected to the network ◆ Packets that not arrive at their destination must be retransmitted ◆ Router computers not retain information about the packets ◆ No global control exists over the network ◆ The TCP/IP Internet Protocol ◆ Set of protocols developed by Vincent Cerf and Robert Kahn ● Transmission ◆ Controls the assembly of a message into smaller packets before transmission, and reassembles them once received ● Internet ◆ ◆ Control Protocol (TCP) Protocol (IP) Rules for routing packets from their source to their destination Replaced NCP as used by ARPANET 10 Web Clients and Servers Client computers typically request services, including printing, information retrieval, and database access ◆ Servers are responsible for processing the clients’ requests ◆ 44 Client/Server Structure of the WWW Figure 2-16 45 Web Client/Server Communication ◆ Two-Tier Client/Server ● All communication takes place between the client on the Internet and the target server at the other end ◆ Request message consists of: ● A request line ● Optional request headers ● An optional entity body 46 Message Flow Between a Web Client and Server Figure 2-17 47 Server Response Message Figure 2-18 48 Web Client/Server Communication Figure 2-19 ◆ Three-Tiered Client/Server ● First tier is the client ● Second tier is the Web server ● Third tier are the applications and their databases (Figure 2-19) 49 Internets, Intranets, and Extranets ◆ Intranets ● Only selected individuals are allowed access ● Low-cost way to distribute corporate information ● Collect and group information for external dissemination ● Infrastructure requirements are usually in place if PCs are on a LAN 50 Internets, Intranets, and Extranets ◆ Extranets ● Connect companies with suppliers or other business partners ● Provide the infrastructure for the coordination of purchases, EDI, and communications ● Use the Internet for communicating among themselves 51 FedEx Ship Page Figure 2-20 52 Internets, Intranets, and Extranets ◆ Public Network ● An extranet that allows the public to access its intranet ● When two or more companies agree to link their intranets using a public network (such as the Internet) ◆ Private Network ● A leased-line connection that physically connects two intranets 53 Internets, Intranets, and Extranets ◆ Virtual Private Network (VPN) ● Uses public networks and protocols to send sensitive data by using “tunneling” or “encapsulation” - private passageways through the Internet ● Designed to save money and create a competitive advantage by alliances formed with cooperating companies 54 Secure VPN Extranet Figure 2-21 55 Internet Connections Options and Tradeoffs ◆ Internet Service Providers (ISPs) offer connection choices to their users ● Plain Old Telephone Service (POTS) Existing telephone lines with modems ◆ Bandwidth of 56Kbps (56,000 bits per second) ◆ ● Integrated ◆ Services Digital Network (ISDN) Bandwidths up to 128Kbps ● Asymmetric ◆ Digital Subscriber Line (ADSL) Upload at 640Kbps, download up to 9Mbps 56 Cable Modems Same broadband coaxial cable that serves cable television ◆ Upstream bandwidths of 300-500 Kbps ◆ Downstream bandwidths of 1.5Mbps ◆ Current “sweet spot” (optimal price and performance) ◆ 57 Internet Connection Choices Figure 2-22 58 ...Objectives General structure of the network of networks supporting the Internet and ecommerce ◆ Protocols that move commerce across the Internet and send/receive e-mail ◆ Internet utility programs... bandwidth tradeoffs ◆ Technology Overview Internet is the most obvious technology needed to conduct e -commerce ◆ Other technologies are also required ◆ ● Database software ● Network switches and hubs... The Internet uses Packet switching ● Files and messages are broken down into packets, which are electronically labeled with their origin and destination ● The destination computer collects the