ECommerce Infrastructure

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E-CommerceInfrastructure Security

• Lecture 2
• Protocols and Markup Languages
• Multi-Tiered Client-Server Architectures

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The Shatterer of Worlds

• Imagine a time without computers, the Internet,
  or E-Commerce
• How did we get here, and whats changed?

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The Internet Effect

• Communication
• Media
• How we work
• How we play
• A distributed world view

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Something Wicked This Way Comes

• Mainframe computing
• Desktop computing environment
• Ubiquitous/mobile computing

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The Circle of Life
Centralized computing
Desktop computing
Networked/distributed computing
ASPs(vive la dumb-terminal!)
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Agenda

• Internet History
• Protocols
• Markup Languages
• Multi-Tiered Architectures
• Security Overview

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Internet History

• Mid 60s
• State of the art was 110bps(2 words per second)
  networks
• 56kbps (550 times faster!)network of 12
  universities/organizations
• Sharing processors was the motivation

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Packet Switching

• Underlying technology of ARPAnet
• Cheaper than circuit switching networks
• Within the packets
• Address information
• Error control information
• Sequencing information
• No longer centrally controlled
• Designed for faults/attacks

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Reality Hits ARPAnet

• E-mail the first Net killer ap
• Communication is king!
• Others want in

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Letting Everyone In the Game

• TCP Transmission Control Protocol
• Used to route data correctly
• Others were developing networks as well
• How do you bring them all together?
• IP Internetworking protocol
• Creates a network of networks
• Thus, TCP/IP

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Then What?

• Businesses seize the golden goose
• There becomes an insatiable desire for
• Increased processor speed
• Increased bandwidth
• Network service providers
• Software

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Enter the PC

• Pioneered by Apple in 1977
• IBM (jumped in later in 1981)
• Creates the desktop mode
• Opens the door for the consumer

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What Was Necessary?

• What elements had to exist before the Web could
  explode as it has done in the last decade?

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What Was Necessary?

• Cheap computing
• Reliable, cheap network technology
• Service Providers
• Delphi, CompuServe, Prodigy, AOL, etc.
• Content
• Easy-to-use software!

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Why Now?

• Computing power is cheap
• People are increasingly mobile
• Browsers have come a long way
• Service providers make it easier
• Huge amounts of content
• Consumer bandwidth is increasing

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Protocols

• You should have had exposure to these in previous
  classes
• You need to know the following terminology so you
  can effectively build E-commerce web sites

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Protocol Terminology

• HTTP - Hypertext Transfer Protocol used for Web
  transmissions
• Client sends request
• Server responds with page/file
• Client closes session
• One request/response/close cycle for each file
  requested

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Protocol Terminology

• SMTP/POP/IMAP
• Used for E-mail transmissions
• FTP
• Used to control the transfer of files from one
  computer to another

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Protocol Application

• Why are protocols needed?
• Why standardize?
• Why have multiple protocols?

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Clearing a Display

• You need to write a network-based, terminal
  program that will run on any platform
• MAC, Unix, Windows, SunOS, etc.
• How can you clear the terminal?

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Clearing the Screen

• CLS in Basic/Dos
• PrintLn() x 25 (or 50) times in Pascal
• clear in UNIX
• Etc.

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Everything In Its Place

• Why should the author/programmer worry about
  implementation?
• Why not let each client machine worry about how
  to accomplish the desired task?
• Improves portability, reuse, etc.

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Enter Markup Languages

• Purpose is to mark documents with tags
• Tags are
• Device-independent
• Language-independent
• Represent properties/attributes of objects within
  a document

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HTML

• This should be review for you if youve taken the
  pre-reqs for these courses(and remember what you
  learned!)

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Hypertext Markup Language

• Subset of SGML (Standard General Markup
  Language)
• Utility of SGML
• Without some of the little-needed features

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Benefits of the HTML Approach

• Separates the content from the implementation
• For example, ltEMgt for emphasis (replacing the
  deprecated ltigt tag)

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Benefits of HTML (cont.)

• Language-independent
• Machine-independent
• Client-side processing

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HTML In ITSK3413/3423

• You should be able to quickly understand HTML
  when viewed native
• Use any authoring tool youd like
• Our goal is results, not specifics

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HTML You Should Know

• Alignment
• Text Formatting
• Graphics ( image maps)
• Links (internal external)
• Tables
• Forms
• Frames

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Our HTML Standard

• Well standardize on HTML 4.01 (the latest)
• All assignments must work in IE 5 or later
• Worry about browser conflicts and
  incompatibilities on the job, not here!

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Enough on HTML Just Do It!
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Multi-Tiered Architecture

• Two approaches well concern ourselves with in
  this course
• Two-Tiered
• Three-Tiered

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How does Web Communication Work?

• DNS Lookup first (distributed lookup)
• Handshake
• SYN from client
• SYN/ACK from server
• ACK from client
• Packets of info until request fulfilled

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The Two-Tiered Approach
TCP/IP
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HTTP Example Client Side

• Client requests page
• Client formats an HTTP request
• The request consists of
• Request line
• Request header
• Optional entity body

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Request Details

• Command (typically GET)
• Filename (requested)
• Protocol being used (client informs)
• Request header additional info as needed
• Entity body used to upload content

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HTTP Example Server Side

• Server responds
• Finds requested file
• Formulates response and sends to client
• Header
• Fields (informs client)
• Body (content)

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The Three-Tiered Approach
TCP/IP
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Additions in Three-Tiered Approach

• Client/Server interactions remain the same
• Additional backend needed
• Fulfill complex client requests
• Business logic
• Data storage
• ERP Enterprise Resource Planning
• Introduces a new interaction

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Server-Backend Communication

• Server analyzes client request
• Realizes it needs the backend
• Server requests a DB transaction with backend
• Backend formulates response and sends to server
• Server formats information into HTML
• Server sends information to client

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Thin Clients

• One approach is to rely upon the client as little
  as possible
• Assume only minimal processor/memory
• Assume minimal browser capability
• What might justify this decision?
• Why might you go a different route?

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Next Week

• Look at various Web servers
• Examine .NET architecture
• Security issues on client server
• Business models hosting options
• Cryptography

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Have a Great Weekend!
FIN