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Electronic Commerce COMP3210: 

Electronic Commerce COMP3210 Dr. Paul Walcott

Contents: 

Contents Part I The Internet and the World Wide Web (WWW) Part II Internet Protocols and addressing Packet-Switched Networks Part III Intranets and Extranets Internet Connection Options

The Internet and the World Wide Web (WWW): 

The Internet and the World Wide Web (WWW) The Internet and the world wide web fuelled the growth of e-commerce In this section of the course we will investigate the origin and structure of the Internet

What Is the Internet?: 

What Is the Internet? The Internet is a large system of inter-connected networks that span the globe The Internet allows communication by e-mail, the reading of on-line newspapers, academic journals and books, the joining of discussion groups, participation in simulations and games as well as downloading software The Internet allows businesses to market and sell products and services

What Is the World Wide Web (WWW)?: 

What Is the World Wide Web (WWW)? The world wide web (WWW) is a subset of the computers on the Internet that connect in a certain way, making their content accessible to each other The WWW includes an easy to use standard interface facilitating ease of use

Origins of the Internet: 

Origins of the Internet In the early 1960s the US department of defense began investigating ways of creating networks of computers that coordinate and control nuclear weapons This network was to withstand attack, so that even if part of it was down it will continue to function This network was to have no central control These new networks required multiple channels to send information (leased lines inadequate)

Origins of the Internet (II): 

Origins of the Internet (II) In 1969 the advanced research agency (ARPA) used this network model to connect four computers This network was called ARPANET During the 1970s and 80s the academic community contributed to this network In the late 1980s this network became the internet

Uses of the Internet: 

Uses of the Internet In 1972 e-mail was created and used by the military and research communities In 1979 the user’s news network (Usenet) was created allowing users to post and read articles (newsgroups) In 1989 the national science foundation (who funded the internet) allowed two commerce mail services, MCI mail and CompuServe In 1990s people worldwide began using the Internet for many purposes including commerce

Internet Growth: 

Internet Growth In 1969 ARPANET (the Internet) connected 4 computers In 1990 the Internet connected 300,000 In 1995 the intranet was privatised The structure was based on four network access points (NAPs) operated by different telecom companies in the US As the Intranet grew, more NAPs were added

Internet Growth: 

Internet Growth The NAPs began selling Internet access rights to large customers Internet service provides (ISPs) sold on the service to small businesses and individuals Growth in Internet hosts rose from under 10 million in 1995 to over 180 million in 2004 Millions of people now use the Internet Billions of dollars change hands from the sales of products and services Estimated number of Web sites is 40 million and billions of web pages

The World Wide Web (WWW): 

The World Wide Web (WWW) The world wide web (or web) is software that runs on machines connected to the Internet The network traffic generated by the web is greater than e-mail, file transfers and other data traffic The web is based on two concepts Hypertext and graphical user interface

Hypertext: 

Hypertext In 1945, Vannevar Bush wrote an article in Atlantic Monthly about a system, called Memex, that would store all a person’s books, records, letters and research results on microfilm Microfilm and indexes would then be used to quickly access this information

Hypertext (II): 

Hypertext (II) In the 1960s, Ted Nelson described a similar system He incorporated a page linking system called hypertext In 1989, Tim Berners-Lee developed the code for a hypertext server A hypertext server is a computer that stores files written in hypertext markup language (HTML) and allow other computers to read it

HTML: 

HTML HTML is a language that includes a set of tags attached to text These tags describe the relationship between text elements A hypertext link (or hyperlink) points to another location in the same or another HTML document (that might be stored on the same or another computer)

Graphical Interfaces for Hypertext: 

Graphical Interfaces for Hypertext Web browsers Allow users to read HTML documents and navigate through them Present an HTML document in a graphical user interface (GUI) In 1993 the web browser Mosiac was developed, later Netscape Navigator and Internet Explorer were developed

Packet-switched Networks: 

Packet-switched Networks A LAN (local area network) is a network of computers in close proximity A WAN (wide area network) network of computers are connected over greater distances Early WANs used leased lines Single path between caller and receiver This is known as circuit switching

Packet-switched Networks (II): 

Packet-switched Networks (II) Messages are broken down into small pieces called packets and are labeled electronically with their origin, sequence and destination addresses Each packet may take a different path The destination computer puts the packets back together in the correct order

Routing Packets : 

Routing Packets Computers that decide how best to forward on a packet to its destination is called a routing computer The actual programs which contains the rules are called routing algorithms These programs apply their routing algorithms to information they have stored in routing tables

Routing Packets (II): 

Routing Packets (II) This information includes lists of connections that lead to particular groups of other routers Which connections to use first Rules for handling instances of heavy packet traffic and network congestion The network devices that move packets from one part of a network to another are called routers

Routing Packets (III): 

Routing Packets (III) When a company connects to the Internet it must connect at least one router to routers owned by other companies that make up the Internet The Internet backbone are a set of routers that handle packet traffic along the Internet’s main connecting points These are very large computers that can handle more than 50 million packets per second A router connected to the Internet always has more than one path to direct packets

Internet Protocols (I): 

Internet Protocols (I) A protocol is a collection of rules for: Formatting, ordering and error checking data that is sent across a network e.g. The protocol might indicate when a sending device has completed sending data The ARPANET network used the network control protocol (NCP) It was based on an open architecture which later became the Internet

Internet Protocols (II): 

Internet Protocols (II) Four key rules used by ARPANET were: Independent networks (e.g. A LAN or WAN) should not require internal changes in order to be connected to the network Packets that do not arrive at their destination must be resent from their source network Router computers act only as receiving and forwarding devices; They do not retain information about the packets they handle No global control of the network exist

Routers: 

Routers The Internet uses routers to isolate each LAN or WAN (mentioned earlier) Each WAN or LAN can use their own protocol for packet traffic within the LAN or WAN The router moves the packets onto the Internet in its standard format

TCP/IP: 

TCP/IP The Internet uses two main protocols (developed by Vicent Cerf and Robert Kahn) Transmission control protocol (TCP) Controls disassembly of message into packets at the origin Reassembles at the destination Internet protocol (IP) Specifies the addressing details for each packet Each packet is labeled with its origin and destination

Internet Protocol version 4 (IPv4): 

Internet Protocol version 4 (IPv4) Uses a 32 bit number to identify each computer Called the IP address (4 billion addresses) IP addresses uses the dotted decimal notation, e.g. 0.0.0.0 or 255.255.255.255

Internet Protocol version 6 (IPv6): 

Internet Protocol version 6 (IPv6) Set to replace version 4 Changes the format of the packets Removes unused fields Uses 128 bit number (2^128 addresses) Eight groups of 16 bits e.g. CD18:0000:0000:AF23:0000:FF9E:61B2:884D To simplify zeroes may be removed CD18:::AF23::FF9E:61B2:884D

IP Addresses: 

IP Addresses IP addresses are assigned by: American Registry for Internet Numbers (ARIN) North America, South America, the Caribbean and sub-Saharan Africa Reséaux IP Européens (RIPE) Europe, Middle East and the rest of Africa Asia-Pacific Network Information Centre (APNIC) Asia-Pacific area

Domain Names (I): 

Domain Names (I) To make Internet addresses easier to remember an alternative, domain names, was provided which used words Domain names May have two or more groups separated by a period, e.g. www.cavehill.uwi.edu Edu – an education institution Cavehill and uwi – the computer’s name www – part of the world wide web Not all computers follow this convention, e.g games.yahoo.com

Domain Names (II): 

Domain Names (II) The rightmost part of the domain name is called the top-level domain (or TLD), e.g. .edu, or .com also Country domains e.g. .bb In 2000 seven new general TLDs were added: .aero – air transport industry .biz – businesses .coop – cooperatives .museum – museums .name – individuals .pro - professionals

Uniform Resource Locator: 

Uniform Resource Locator The combination of the domain name and the protocol name is called the uniform resource locator (URL) E.g. http://www.yahoo.com http is the protocol www.yahoo.com is the domain name

Hypertext Transfer Protocol: 

Hypertext Transfer Protocol The hypertext transfer protocol (HTTP) was developed by Tim Berners-Lee in 1991 Client Web Server Request sent to Web server Response sent with files (one for each Web page, image, sound clip etc.)

Electronic Mail Protocols (I): 

Electronic Mail Protocols (I) Client server model used Organisation has an email server devoted to handling email Stores and forwards email messages Individuals uses email client software to read and send email (e.g. Microsoft Outlook, or Netscape Messenger)

Electronic Mail Protocols (II): 

Electronic Mail Protocols (II) Simple Mail Transfer Protocol (SMTP) Specifies format of mail messages Post Office Protocol (POP) tells the email server to: Send mail to the user’s computer and delete it from the server Send mail to the user’s computer and do not delete it from the server Ask whether new mail has arrived

Electronic Mail Protocols (III): 

Electronic Mail Protocols (III) Interactive Mail Access Protocol (IMAP) Newer than POP, provides similar functions with additional features e.g. can send specific messages to the client rather than all the messages A user can view email message headers and the sender’s name before downloading the entire message Allows users to delete and search mailboxes held on the email server

Electronic Mail Protocols (IV): 

Electronic Mail Protocols (IV) The disadvantages of POP You can only access messages from one PC The disadvantage of IMAP Since email is stored on the email server, there is a need for more and more expensive (high speed) storage space

Intranets and Extranets: 

Intranets and Extranets An Intranet is an interconnected network (internet) that does not extend beyond the organisation that created it An extranet is an intranet that has extended to include specific entities outside of the organisation, e.g. business partners, customers or suppliers Extranets can replace faxes, telephones, email and overnight carriers, at a lower cost

Intranets: 

Intranets Low cost distribution of internal corporate information Based on client server model Intranets use Web browsers, internet-based protocols including TCP/IP, FTP, Telnet, HTML and HTTP Distributing paper is often more expensive Intranets can also be used to provide software updates and patches, which update users computers automatically – using scripts

Extranet: 

Extranet Networks that connect companies with suppliers, business partners and authorised users Each user has access to the databases, files and other information stored on computers connected to the extranet Fedex changed from an Intranet to Extranet for package tracking on their Web site

Public and Private Networks: 

Public and Private Networks A public network is any network available to the public, e.g. Internet A private network is a private (e.g leased) line between two computers Leased line is a permanent connection between two points line is always active (unlike telephone connection) The advantage is security (only the two parties can connect to the network) The disadvantage is the cost due to the scaling problem: to connect 5 pairs, 5 lines are required

Virtual Private Networks (I): 

Virtual Private Networks (I) A VPN is an extranet that uses public networks and their protocols to send sensitive information using IP tunneling IP tunneling creates a private passageway through the public Internet that provides secure transmissions

Virtual Private Networks (II): 

Virtual Private Networks (II) VPN software encrypts the package content and places it into another packet (encapsulation) The outer packet is called an IP wrapper The receiving computer decrypts it using the (VPN software) The connection is ‘virtual’ since it is only temporary, it is created when information needs to be transmitted A VPN is an extranet, but not every extranet is a VPN

Internet Connection Options: 

Internet Connection Options ISPs provide several ways to connect to the Internet Voice grade telephone lines Broadband connections Leased lines Wireless The major distinguishing factor is bandwidth (the amount of data that can be transferred per unit of time)

Bandwidth and Connections: 

Bandwidth and Connections Symmetric connection: provides the same bandwidth in both directions Asymmetric connections: provide different bandwidths for either direction Upstream bandwidth (upload bandwidth): the amount of information that can travel from the user to the Internet in a given amount of time Downstream bandwidth (download or downlink bandwidth): the amount of information that can be transferred from the Internet to the user in an amount of time

Voice-grade Telephone Connections: 

Voice-grade Telephone Connections Most common way to connect to ISP Modem (analog) connected to telephone lines POTS (plain old telephone service) 28 to 56Kbps Digital subscriber line (DSL) protocol Does not use a modem Uses a piece of network equipment similar to a network switch Integrated services digital network (ISDN) first used DSL protocol suite in 1984 More expensive, but offers bandwidth of 128Kbps – 256Kbps

Broadband Connections (I): 

Broadband Connections (I) Connections that operate at speeds higher than 200Kbps are considered broadband One of the latest is asymmetric digital subscriber line (ADSL) Bandwidths from 100-640Kbps upstream and from 1.5 to 9 Mbps downstream For businesses a high-speed DSL (HDSL) is available 768Kbps of symmetric bandwidth

Broadband Connections (II): 

Broadband Connections (II) Cable modems (connected to the same broadband coaxial cable that serves a television) Upstream bandwidth of 300Kbps to 1 Mbps and downstream bandwidth of 10Mbps

DSL v Cable: 

DSL v Cable DSL is a private line with no competing traffic Cable connections bandwidth change with the user load (number of subscribers using the service) Problems Web users in rural areas often do not have cable access and have limited telephone access (low cost voice-grade lines, rather than data-grade lines) thus bandwidth is limited (<14Kbps)

Leased-Line Connections: 

Leased-Line Connections Large firms with a large amounts of Internet traffic can lease lines from telecommunication carriers Various technologies are used; classified by the amount of telephone lines they include: DS0 (digital signal zero) carries one digital signal (64Kbps) T1 (or DS1) carries 24 DS0 lines (1.544Mbps) Fractional T1 (128Kbps and upwards) T3 (or DS3) carries 30 T1 lines (44.736Mbps) Connections more expensive than POTS, ISDN and DSL

Wireless Connections: 

Wireless Connections Satellite Bluetooth Wireless Ethernet (Wi-Fi) Fixed-Point Wireless Cellular Telephone Networks

Satellite: 

Satellite Satellite microwave transmissions Customer placed receiving dish in yard Download bandwidth of around 500 kbps Maximum upload bandwidth of 150kbps Self installation makes cost lower

Bluetooth: 

Bluetooth One of the first wireless protocols Operates reliably over 35 feet and can be part of up to 10 networks of eight devices each (personal area networks, or PANs) Bandwidth of 722kbps Good for wireless printing

Bluetooth Advantages: 

Bluetooth Advantages Bluetooth technology consumes very little power Bluetooth devices can discover each other and exchange information automatically (e.g. a user can print to a printer on a network without logging on)

Wireless Ethernet (Wi-Fi) (802.11b): 

Wireless Ethernet (Wi-Fi) (802.11b) Most common wireless on LANs Bandwidth 11Mbps at 300 feet A computer with a Wi-Fi network can communicate with a wireless access point (WAP) to become a part of the network

Wireless Ethernet Advantages: 

Wireless Ethernet Advantages Wi-Fi devices can roam, i.e. shift from one WAP to another without user intervention Increasingly WAPs are becoming available in public places, e.g. airports

Wireless Ethernet Developments: 

Wireless Ethernet Developments In 2002 an improved version of Wi-Fi, called 802.11a was introduced The 802.11a protocol is capable of transmitting at speeds up to 54Mbps 802.11a is not compatible with 802.11b Later in 2002, the 802.11g protocol was introduced which is compatible with 802.11b devices and has speeds of 54Mbps In 2004-2005, 802.11n expected (320Mbps)

Fixed Point Wireless: 

Fixed Point Wireless Uses a system of repeaters (transmitter-receiver devices) to forward a radio signal from the ISP to customers Users’ antennas are connected to a device that converts radio signals to Wi-Fi packets which are sent to their computers

Cellular Telephone Networks: 

Cellular Telephone Networks In 2003, about 500 million mobile (cell) phones worldwide Originally slow data communication (10 kbps – 384kbps) Third generation cell phones Up to 2 Mbps

Cellular Telephone Networks (I): 

Cellular Telephone Networks (I) Cell phones send and receive messages using the short message service (SMS) protocol Some cell phones include Web browser which provide web access, email, short message service Companies also sell Internet access through their cellular networks Fixed fee plus charge for amount of data transferred Business potential of mobile commerce Companies are identifying the kinds of resources individuals might want to access (and pay for) using wireless devices

Definitions: 

Definitions A computer network is any technology that allows more than one computer to be connected together