E-Commerce Infrastructures

Internet and Web Technologies

Learning Objectives (1/2) Growth, and structure of the

Internet Private and public networks Internet infrastructure Developing applications for the Web Limitations of Web technologies and

how to address them

Learning Objectives (2/2) Internets, intranets, and

extranets Options for connecting to the

Internet Future developments: High

speed networks, the Semantic Web, mobile networking

Technology Overview Technical foundations of e-commerce:

Computer networks including the Internet. Computing devices (clients and servers)

running operating systems, database managers, web

servers, application servers, encryption software, security software, multimedia creation and viewing software, and the graphical user interface

The Internet

Hardware• The hardware that connects the

computers together • The hardware that connects the

networks together Internet protocols. Rapid change in these technologies

requires businesses to be flexible.

Packet-Switching

The Internet uses packet switching Files are broken down into packets

that are labeled with their origin, sequence, and destination addresses.

This fact has very important consequences for both the performance and the security of e-commerce systems

Routing

The programs on these routers use ‘routing algorithms’ that call upon their ‘routing tables’ to determine the best path to send each packet.

When packets leave a network to travel on the Internet, they are translated into a standard format by the router.

These routers and the telecommunication lines connecting them are referred to as ‘the Internet backbone’.

Between seller and customer there are several other actors who have a role to play

Routing Packets

Internet Protocols

The open architecture has four key rules that have contributed to the success of the Internet.

• 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; they do not retain information about the packets that they handle.

• No global control exists over the network.

Another look at Domain Names

Domain names identify who you are (or else establishes your corporate identity)

.com .biz means you are a business .org means “not for profit” .uk means you are in the UK CNN.com displays your trade name Trademark law applies (Domain name wars)

This has implications for e-commerce with regard to customer assumptions about you

It costs!

Web Page Delivery

Hypertext Transfer Protocol (HTTP) is the set of rules for delivering Web pages over the Internet

HTTP uses the client/server model• The client opens an HTTP session and sends a

request to a server• The server returns an HTTP response

message which contains data. After this, they forget about each other – this

has very significant implications for Web (and e-commerce) application development.

Email

Email is also transferred over the Internet. Email also depends on intermediate systems

to move from one place to the other Email is send to a specific address (is this

the same as knowing it gets to a particular individual?)

Email = Identity (is this true?) Email is related to corporate entities (via the

name system NOT DNS)

Web Markup Languages

Web pages are marked with tags to indicate the display and formatting of page elements

They create static pages Useful for developing Uis HTML, XML and the like

Web Markup Languages

Programming Languages

Scripts embedded in HTML can execute programs on client computers that display those pages in the browser

Scripts at the server can do complex processing and produce advanced content

Language frameworks like J2EE and .NET can be used to develop full blown interactive applications (more on this next time)

Persistence Cookies

Data stored at the browser Programmatically controlled by the server

Hidden HTML forms URL re-writing

http://www.amazon.com/exec/obidos/detail/-/0415097762/104-6915588-4331902

Intranets and Extranets

Intranet• An intranet is an interconnected network (or

internet – small “i” intended) that does not extend beyond the organization that created it

• Intranets are an extremely popular and low-cost way to distribute corporate information

• An intranet uses Web browsers and Internet-based protocols (including TCP/IP, FTP, Telnet, HTML, and HTTP) and often includes a firewall

Intranets and Extranets

Extranet• Extranets are intranets that have

been extended to include specific entities outside the boundaries of the organization (business partners, suppliers, etc.)

• An extranet can be a public network, a secure (private) network, or a virtual private network (VPN).

Intranets and Extranets

A public network is any computer or telecommunications network that is available to the public

A private network is a private, leased-line connection between two companies that physically connects their intranets to one another

A VPN extranet is a network 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’

Internet Connection Options The Internet is a set of interconnected

networks Large firms that provide Internet access

to other businesses are called Internet Access Providers (IAPs) or Internet Service Providers (ISPs)

Connectivity Overview

The most common connection options that ISPs offer to the Internet are telephone, broadband, leased-line, and wireless

Bandwidth is the amount of data that can travel through a communication line per unit of time

Bandwidth can differ for data traveling to or from the ISP

Voice Connections

The most common way to connect to an ISP is through a modem connected to your local telephone service provider

POTS uses existing telephone lines and an analog modem to provide a bandwidth of 28-56 Kbps

ISDN uses the DSL protocol suite to offer bandwidths between 128-256 Kbps

Suitable for consumer (implications for design of e-commerce sites)

Broadband Connections

Connections that operate at speeds of greater than 200 Kbps are called broadband services

ADSL uses the DSL protocol to provide bandwidths between 100-640 Kbps upstream and 1.5-9 Mbps downstream

Cable modems provide transmission speeds between 300 Kbps-1 Mbps from the client to the server and a downstream rate as high as 10 Mbps

Satellite microwave transmissions handle Internet downloads at speeds around 500 Kbps

Suitable for SMEs

Leased-Line Connections

Large firms can connect to an ISP using higher-bandwidth connections that they can lease from telecommunications carriers

A T1 (E1) line operates at 1.544 Mbps and a T3 (E3) line operates at 44.736 Mbps

Expensive – usually can be afforded only by larger business

Internet Options

Wireless Connections

Many researchers and business managers see great potential for wireless networks and the devices connected to them

The term m-commerce (mobile commerce) is used to describe the kinds of resources people might want to access using devices that have wireless connections

Cellular vs. WLAN

Internet2

Internet2 is an experimental test bed for new networking technologies that is separate from the original Internet

200 universities and a number of corporations joined together to create this network

It has achieved bandwidths of 10 Gbps Internet2 promises to be the proving ground

for new technologies and applications of those technologies that will eventually find their way to the Internet

Grid computing Computing as utility Grid as in the “electric grid” Computation, storage, processes Scientific applications currently Look at planet-lab.org