ECommerce Fundamentals and Applications Chapter 2 Internet and

E-Commerce: Fundamentals and Applications Chapter 2 : Internet and World Wide Web ________________________________________________________ E-Commerce: Fundamentals and Applications 1 Wiley and the book authors, 2001

Outline n n n n n An Overview of the internet Brief history of the web Web system architecture Uniform resource locator Overview of the hypertext transfer protocol Hypertext Transfer Protocol(HTTP) Generation of dynamic web pages Cookies HTTP/1. 1 ________________________________________________________ E-Commerce: Fundamentals and Applications 2 Wiley and the book authors, 2001

Basic Network Architecture R R Internet R modem ADSL ISP Dedicated Connection Private network R : Router ________________________________________________________ E-Commerce: Fundamentals and Applications 3 Wiley and the book authors, 2001

Layered Model for the Internet Application Layer Transport Layer Network Layer Link Layer ________________________________________________________ E-Commerce: Fundamentals and Applications 4 Wiley and the book authors, 2001

Processing at Each Layer Application Header Application Data Application Layer TCP Header Application Data TCP Layer IP Header TCP Header Application Data IP Layer Link Header IP Header TCP Header Application Data Link Layer ________________________________________________________ E-Commerce: Fundamentals and Applications 5 Wiley and the book authors, 2001

Transfer of Packets Host A Application data Host B Application TCP IP IP Link Application data ________________________________________________________ E-Commerce: Fundamentals and Applications 6 Wiley and the book authors, 2001

Different Internet Access Methods Access method Maximum data rate Telephone modem 24 -56 Kbps Ethernet (Local area network) 10/1000 Mbps Integrated Services Digital Network Basic Rate Interface (ISDN BRI) 56 – 128 Kbps Cable modem 30 Mbps (theoretical) 1. 5 Mbps shared (practical) Asymmetric Digital Subscriber Line (ADSL) 1. 5 Mbps - 9 Mbps (from network to users) 128 Kbps – 9 Mbps (from users to network) Wireless local area network (IEEE 802. 11) 1 -56 Mbps ________________________________________________________ E-Commerce: Fundamentals and Applications 7 Wiley and the book authors, 2001

Common Application Layer Protocols Protocol Purpose Simple mail transfer protocol Support email services File transfer protocol Support file transfer services TELNET Allow users to log in remote host Hypertext transfer protocol Support communications between a Web client and a Web server ________________________________________________________ E-Commerce: Fundamentals and Applications 8 Wiley and the book authors, 2001

Part of the DNS tree Root com edu gov mil net org hk jp …. . vbs www ________________________________________________________ E-Commerce: Fundamentals and Applications 9 Wiley and the book authors, 2001

URL n Used to identify web pages Ø n Example: Ø n protocol: //domain_name: port/directory/resource http: //www. vbs. com/welcome/main. html General format: Ø protocol: //username: password@domain_name: port/directory/resource ________________________________________________________ E-Commerce: Fundamentals and Applications 10 Wiley and the book authors, 2001

Request Methods in HTTP/1. 0 n n n GET HEAD POST ________________________________________________________ E-Commerce: Fundamentals and Applications 11 Wiley and the book authors, 2001

Commonly Used Status Codes in HTTP/1. 0 Status code Status message 200 OK 201 Created 204 No content 301 Moved Permanently 302 Moved Temporarily 304 Not Modified 400 Bad Request 401 Unauthorized 403 Forbidden 404 Not Found ________________________________________________________ E-Commerce: Fundamentals and Applications 12 Wiley and the book authors, 2001

Commonly Used Response Header in HTTP/1. 0 n n n Location Server WWW-Authenticate ________________________________________________________ E-Commerce: Fundamentals and Applications 13 Wiley and the book authors, 2001

Generating dynamic web pages n Attach names and values at the end of the URL using a query string: n ? name 1=value 1& name 2=value 2&…. & name. N=value. N n Example: Ø Ø http: //www. vbs. com/servlet/booksearch? title=ecommerce&year=2000 GET /servlet/booksearch? title=ecommerce&year=2000 HTTP/1. 0 ________________________________________________________ E-Commerce: Fundamentals and Applications 14 Wiley and the book authors, 2001

Cookies n n n Invented by Netscape. Save state data at client side. Visit http: //www. netscape. com/newsref/std/cookie_spec. html Standardized in RFC 2109 Server Ø n Set-Cookie: Name=Value Client Ø Cookie: Name=Value ________________________________________________________ E-Commerce: Fundamentals and Applications 15 Wiley and the book authors, 2001

HTTP/1. 1 n n Persistent connection Pipelining Efficient use of IP addresses Best support for: Ø Ø n caching authentication language encoding More request methods ________________________________________________________ E-Commerce: Fundamentals and Applications 16 Wiley and the book authors, 2001