05TechnologyandInfrastructure

Electronic Commerce
Technology & Infrastructure
Prepared by: LEL First Prepared on: 28-2-2005 Last Modified on: Quality checked by: Module Group Copyright 2004 Asia Pacific Institute of Information Technology
HISTORY OF THE INTERNET • ARPANET (1960s-80s):
• NSFNet (US-DOD, 1980s): • Today’s Internet (1995-):
– US-DOD funded research to explore creating a computer network that can survive wars. – 4 nodes in 1960: UCLA, SRI, Utah and UCSB. – 15 nodes in 1971 connecting east and west coast universities. – Started in 1986 connecting 5 supercomputing centers: Pitt/CMU, UIUC (NCSA), UCSD, Cornell, Princeton. – Connected to networks in Europe and Canada in 1988-1990. – Over 65,000 networks and 35M+ hosts worldwide (and growing). – Reaches 57M people in US; 90M worldwng peak capacity; backbone recently replaced by a new high-capacity network (Internet2).
INTERNET CONCEPTS: SWITCHING
• Switching:
– The process of moving messages using temporary connections on a connected network of computers/nodes.
• Packet-switching (Internet):
– Three types:
• Local area network (LAN): Network of computers located in physical proximity (same room or building). • Wide area network (WAN): Network spanning geographical distances (countries or continents). • Metropolitan area network (MAN): Network spanning cities. • Personal area network (PAN): Home networks.
• Circuit switching:
– Entire message transmitted as a whole (no packets) via a single temporary path over switches/routers.
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• Web (hypertext) communication:
– – – – Requested by web clients (browsers) such as Internet Explorer. Responded by web servers such as Internet Information Server. Hypertext server stores files written in hypertext markup language Tim Berners-Lee developed code for first hypertext server and client.
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GROWTH OF THE INTERNET
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INTERNET ARCHITECTURE
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• Switches:
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INTERNET CONCEPTS: PROTOCOLS
• TCP/IP protocol:
– Collection of rules for formatting, ordering, and error-checking data sent over the Internet. – Designed by Kahn & Cerf in 1974; became ARPANET standard in 1984.
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NETWORKS, INTERNET, AND WEB
• Computer network:
– A set of interconnected computers linked via wireline or wireless means for sharing data/resources among each other.
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CLASS OBJECTIVES
• 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 history and use of markup languages on the Web, including SGML, HTML, and XML • How HTML tags and links work on the World Wide Web • The differences among internets, intranets, and extranets • Internet connection options, including cost and bandwidth • Internet2 and the Semantic Web
Learning Outcomes
At the end of the lecture, you should be able to: • • Differentiate Web Server Hardware and Software from E-Commerce Identify the desirable features of web servers, popular Web server programmes, and other software that works with Web server software to accomplish the basic operations of a Web site
• Transmission Control Protocol (TCP):
– Rules that define how messages are broken into packets for transmission over the Internet. – Also controls reassembly of packets at the destination nodes.
• Internet:
– A WAN connecting computer networks across the globe.
• World Wide Web:
– A subset of computers on the Internet running the HTTP protocol.
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– Before transmission, messages are broken down into small pieces called packets (packetization). – Each packet is affixed with the address of the destination computer (addressing). – Packets travel independently from source to destination via a series of switches/routers connected the Internet. – Packets are reassembled at destination back into original message.
• E-mail communication:
– Requested by e-mail clients such as Microsoft Outlook. – Responded by e-mail servers such as Microsoft Exchange.
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INTERNET CONCEPTS: C/S ARCHITECTURE
• Client/server architecture:
– All computers connected to the Internet are treated equally (peers). – Computers request services/data from each other; requesting computers are clients, responding computers are servers. – Clients and servers are processes, not machines.
INTERNET CONCEPTS: NODES
• Routers:
– Computers that connect internal networks to the Internet. – Requires specialized hardware and software that support Internet routing protocols and TCP/IP stacks.. – Network access points (NAP) and routers used by local ISPs to control access to Internet. – Computers that manage packet traffic on the Internet. – Use routing algorithms to decide which path to use to forward packets to destination. – Requires specialized hardware and software.