Download Powerpoint - Lyle School of Engineering

E-Commerce
Architectures
and Technologies
Rob Oshana
Southern Methodist
University
Agenda
• Business Models
• Business to Business and Business
to Consumer
• The beginning - Electronic Data
Interchange (EDI)
• Network Architectures
• Internet and Web Architectures
• E-Commerce Architectures
• Intranet, Extranet, Internet
• IBM E-Commerce Success Steps
Business to Consumer
Business to Business
Indirect supplier 1
Indirect supplier 2
Direct Suppliers
Transportation of Supplies
Corporation
Government
Manufacturer
Sales
Distribution
IT
Electronic
UPS/Fedex
Marketing
Financial Institution
Credit Card
Processing
Services
Store Front
Layered Architecture for
eBusiness
Electronic Commerce Applications
(Supply chain management, video on demand,
on-line marketing and advertising, home shopping)
Common Business Services Infrastructure
(security/authentication, electronic payment,
directories/catalog)
Messaging and information distribution infrastructure
(EDI, e-mail, HTTP)
Multimedia content and network publishing infrastructure
(HTML, Java, WWW)
Network Infrastructure
(telecom, cable TV, wireless, internet)
Vendor Centric Versus
Customer Centric
Customer A
Customer B
Vendor
Vendor Centric
Customer C
Customer D
Vendor A
Vendor B
Customer
Customer Centric
Vendor C
Vendor D
User
Buyer
Procurement
Server
Internal
External
Server
Browser
Intranet
Server
Internal
Intranet
Browser
Admin
Functional
Units
User
Production
Supplier
Other
Firewall
Server
External
Internet
Supplier
Functional
Units
connection
Use
r
Browser
Intranet
Web Architecture
Server
External
Server
Internal
The Web Commercial Community
Consumer
University
Software
Developers
Quicken
Online
resources
Search Engines
Simulations GDSS
Mutual
Fund DB
Bank
Online
Magazines
Web
catalogs
Payment System
Products on the Web
WebAd
Manager
Cybermediaries
Web compatible software
Virtual
Reality
Online
Services
Supplier
Delivery Service
Web
DBMS
Web-based Transactions
Web Business Community
Buyer
1. Select
product via
browsers.
Seller
3. Buyer pays by
credit cards
Browser
5. Ship
product
to buyer
2. Put selected
merchandise
into shopping
cart.
Web catalog
system
Payment
System
4. Authorization from
bank or credit card
company
Bank
1. Provide product
and pricing
information.
2. Update info
periodically.
ProductAd
Manager
Manages
product ad
etc.
Web Catalog
Product
Product
Components of the Web
DB
Web Browser
TCP/IP
based network
(HTTP)
Web Clients
1. Browser establishes
connection with server.
2. Browser issues request
to server.
3. Server sends a
response (page or
graphics)
4. Both browser and
server disconnect and
the transaction ends.
CGI
Web Servers
(web pages)
HTML describes
the contents of
each Web page
Content
Software
applications
Common
Gateway
Interface (CGI)
CGI defines how
external
applications can
interact with Web
servers
Business-to-Business
and Business-to-Consumer
Business-to-Business
• The selling of products and services
between corporations and the
automation of systems via
integration
• Typical players involved
– suppliers
– distributors
– manufacturers
– stores
Business to Business
• Most of the attention recently
focused on prominent well
established firms
– Cisco
– Dell
– Eliminate old-economy middlemen and
sell directly to business customers
Business-to-Business
• Most of the transactions occur
directly between two systems
– automation of the supply chain
– Supply Chain Management; the process
of tying together multiple suppliers of
goods to create a final product
• Daimler-Chrysler Corporation
– over 20,000 suppliers of parts
– SPIN B2B solution increased
productivity over 20% in first year
Business-to-Business
• Other forms of B2B E-Commerce
– Malls
• QVC; offers a common interface for buyers
to access different supppliers
• Buyers manage their own back end DBs
(product information)
• Helps retailers collaborate with worldwide
supply chain
• www.qvc.com
Business-to-Business
• Other forms of B2B E-Commerce
– Catalogs
• Used for purchases between companies
• Allow corporate buyers to search for
products based on features or price
• Single interface for individual sellers or
multiple sellers of similar products
• Benefits include
– ease of use
– flexibility
– easy updating
Key Themes for B2B
• B2B will be much larger than B2C
• The timing is now
• Exchanges will introduce
unprecedented market transparency
• B2B winners will establish platforms
that link deeply with customers (ehub)
• Many B2B business models will fail
• Buyers and Suppliers win
What Problems are We
Solving?
• Commerce is fragmented by
geography
• Most interactions between
businesses are complex and laborand information sensitive
• Supply chains are bloated with
excess inventory because of the
inability to see and plan for the right
mixes and volume of products
A Question of Transparency
• Price transparency
• Availability
transparency
• Supplier
transparency
• Product
transparency
Customer Feeding Frenzy:
e-retailers vie for $185
billion
• Latest consumer ecommerce forecasts estimate
at least a five-fold increase in
sales from 1999 to 2003.
Forrester Research issued the
most detailed - and
aggressive - outlook,
predicting $185 billion in U.S.
e-commerce sales by 2004.
Economic Spotlight: IT and Net
Industries Drive U.S. Economy
The U.S. Department of
Commerce has compiled
the latest analysis on the
impact of the information
technology and Internet
industries in "The
Emerging Digital Economy
II." Available at
www.ecommerce.gov, the
report shows these
industries contributed 29
percent of the nation's
economic growth in 1998.
The Economic Impact of E-commerce
Toy-giant Mattel will spend $50
million to launch an e-commerce
venture that the company says will
bring in $60 million this year, at
gross margins greater than those of
its traditional business. Sound
good? A report from the Organization
for Economic Cooperation and
Development policy group has
compiled over 150 pages of
economic reasons why governments
and businesses worldwide should
pay attention to the ramifications of
digital commerce.
The Economic Impact of E-commerce
“The Economic and Social Impact of
Electronic Commerce” report says
business-to-business sales will help drive ecommerce revenues to $1 trillion in the 2003
to 2005 time frame. Companies like Mattel
are taking advantage of the economic
efficiencies of e-commerce: low-cost
distribution, ordering and customer service,
improved productivity and tighter inventory
control. The OECD says the Net economy
will result in lower prices for consumers,
better information access and increased
competitiveness of small and midsize
businesses. It will also pave the way for a
true global trading community.
The Economic Impact of E-commerce
Equal access to e-commerce
benefits is critical to the Internet
Economy. Rich folks are more likely
to have Internet access than poor
folks in every country studied by the
OECD. The report warns of a
continuing worldwide shortage of
skilled technology professionals. But
an OECD analysis shows that, in the
U.S. at least, traditional retail and
information workers will have less to
fear from a digital marketplace than
their European counterparts.
B-to-B Forecasts
B-to-B Forecasts
But Gartner’s corporate focus
is understandable, given the
way b-to-b conversion
happens. “B-to-b gets
adopted in chunks,” says
Knight. “You’ve got entire
companies, entire supply
chains adopting e-commerce.
It’s like a snowball effect.”
Despite methodological and
definitional variations,
everyone agrees b-to-b will
be big: in the neighborhood
of $2 trillion in the U.S. by
2003, up from approximately
$100 billion in 1999.
Behind the Numbers:
The Mystery of B-to-B Forecasts
Revealed
One of the segments
expected to grow the fastest
is “e-marketplaces,” third
parties that bring together
multiple buyers and sellers
online. According to Gartner,
there were about 30 emarketplaces in January 1999
and 300 by December.
Forrester Research predicts
that by 2004 more than half of
all online b-to-b trade will be
marketplace-driven.
Online Population Spotlight:
Net Businesses Go Back to College
Every year, marketers spend millions of
dollars targeting college students just
entering their prime as consumers. Now
dozens of Net firms want in on the act.
Source: Student Monitor
Source: Cyber Dialogue
Geographic Market
Fragmentation
S
S
B
B
S
S
B
S
S B
B
Geography 1
B
S
B
B
S
S
B Premier
B
seller
S
Source: Morgan Stanley Dean Witter Internet Research
Premier
buyer
B
S
B
S
Geography 3
Geography 2
Enhanced Buyer and Seller
Discovery
S
B
S
S
S
S
S
B
S
S
S
Source: Morgan Stanley Dean Witter Internet Research
B
B
B B
B
B
B
The Implications
• Strong competitors
become dominant in
efficient markets
• Weaker competitors
get weaker
• Intermediaries at risk
• Suppliers become
more specialized
• Buyers
initiate/terminate
relationships more
easily
• Uniform prices
Time is Right for B2B
•
•
•
•
•
•
•
•
•
Infrastructure ready
Board room acceptance
Speed and simplicity
Lure of cost savings and
efficiency
Early adopters common
Year of evaluation behind
us
Buyers are getting equity
Vendors are pushing the
next thing
Well financed start ups
and a good economy
B2B - Past, Present, and
Future
• Phase 1 - Batch
EDI
• Phase 2 - Basic ECommerce
• Phase 3 Communities of
commerce
• Phase 4 Collaborative
commerce
Business-to-Consumer
• Interactions and transactions
between a company and its
consumers
• Focus is on selling goods and
services and marketing to the
consumer
• Dell, Amazon.com, eBay
Traditional vs Direct Selling
Chain
Supplier
Supplier
Manufacturer
Manufacturer
Distributor
Distributor
Wholesaler
Wholesaler
Reseller
Reseller
Customer
Customer
Business Models
Introduction to Business
Segments
• Consumer Retail
– businesses selling physical goods to an
individual end consumer
• Business-to-Business cataloging
– businesses with online catalogs selling
products to other businesses
• Information commerce
– businesses distributing digital goods
Segment Granularity, Market
Size, and Timing
• Segmentation because of focus
– concentrating on exactly those
elements that are essential to the
application or market
– not diverting effort towards those
elements that are either not needed or
not appreciated by the customer
Segment Granularity, Market
Size, and Timing
• Difficult to get right
– too broad => development resources
may not stretch across all necessary
features
– too narrow => market may not be large
enough to support the business
Segment Similarities and
Differences
• All have the need to attract
customers, present products,
assemble orders, do transactions,
accomplish fulfillment, and deliver
customer service
• Retail segment has more need for
merchandising capability
Segment Similarities and
Differences
• B2B have a greater need for payment
by purchase order and for approval
workflow
• Information commerce has a great
need for online fulfillment
Consumer Retail - Value
Proposition
• Ability to reach a global market
• Reduced marketing and selling
expenses
• Increased efficiency of operations
• Ability to target consumers more
precisely
• Ability to convey more accurate
product and availability information
Consumer Retail - System
Functionality
• Small shop
– static catalog and simple requirements
• Medium sized direct marketing
– product database and display templates
• Large Retailer
– Enterprise Resource Planning (ERP)
Attract - Advertising and
Marketing
• Advertising
– banners on popular sites
– e-mail newsletters
– listings on widely used search engines
• Expense for the retailer
• Revenue to a vendor in the
information commerce segment
Attract - Advertising and
Marketing
• Coupons
– internet-based digital coupons may
directly link to a transaction service
• Sales
• Promotions
• Frequent buyer programs
Attract - Advertising and
Marketing
• One-to-One marketing
– Internet removes geographical basis for
convenience
– price is always a difficult basis for
competition
– leaves quality of service
– knowing a lot about the customer helps
provide high quality service
Interact - Content
• Registration with Internet search
engines
• Printed hypertext links on traditional
menus, catalogs, and advertising
• Internet advertising on popular or
related sites
Act - Order Processing
• Shopping cart or order aggregation
function
– logical DB ot items considered for
purchase
• Order validation
– validation based on business rules
• Application of coupons or other
discounts
– affinity programs and quantity
discounts
Act - Order Processing
• Cross selling
– offer buyer additional merchandise
based on contents of shopping cart
• Calculation of sales and other taxes
– complex rule sets involving tax
classification of product, location and
tax status of buyer and seller
• Calculation of shipping and delivery
charges
– bundled into price or extra and different
forms
Act - Order Processing
• Presentation of the rolled-up order to
the buyer
– reduces downstream issues
• customer service
• return
• dispute handling
Act - Order Processing
• Electronic cash
– low transaction cost
• Microtransactions and tokens
– fractions of a penny transactions
• Transaction Aggregation
– charging multiple events by the batch
– taxi meter or charge up
• meter accumulates usage charges
– parking meter or pay down
• buyer prepays a lump sum
Act - Fulfillment
• Traditional channels for physical
goods
• On line for information commerce
• Downloading
– charge for the download itself
• appropriate for small downloads (unlikely to
fail)
– charge for access rights to the
download area
• access for a reasonable amount of time to
do all the downloads
Act - Fulfillment
– charge for a license key
• delivering the key and content separately
may be difficult
– planning for download failures
• Subscriptions; ongoing access
• Push Content; actively delivered by
the content service
React - Customer Service
• Key issues are the same
– I didn’t buy that
– I didn’t receive the delivery (or broken)
– I didn’t like what I received
– I was charged the wrong amount
– With E-Commerce technology ensures
that “I didn’t receive the delivery” is rare
Copy Protection and Rights
Management
• Digital content can be copied
• Don’t worry about it
• Make copying very difficult
– container technology or license keys
• Make tracing the thief easy
– register each copy (fingerprint or
watermark)
• Make paying for copies easy
– honest customers will use it
Electronic Data Interchange
EDI
• Inter-organizational exchange
– business documents
– standardized electrical form
– directly between computer applications
• purchase orders
• invoices
• material releases
– easy and inexpensive and structured
Industries that use EDI
•
•
•
•
•
•
•
•
Automotive
Retail
Chemical
Electronics
Petroleum
Metals
Paper and Office products
Still a relatively small percentage
(about 100,000 companies)
Key Aspects of EDI
• Utilization of an electronic
transmission medium (VAN)
• Use of structured formatted
messages
• Relatively fast delivery of electronic
documents (hours or minutes)
• Direct communication between
applications (rather than just
systems)
EDI costs
• Reaching a legal agreement
(lawyers!)
• Building and installing the EDI
system
• Modifying and interfacing with the
existing computer system
• Obtaining network services
• Testing and installation
• Reengineering of internal processes
• Training
EDI Costs
• Rate-of return analysis should be
done
– # transactions to amortize the cost
effectively
– turnkey systems payment about 36
months
• Cost shifting
– dominant purchaser
– better economies of scale
– smaller companies have higher
transaction cost
System Approach
• Single dedicated PC
• Group of computer performing many
related functions
• Individual modems or modem pool
• Server as the interface to outside
– other computers for business
applications
– dialup with a ISDN or dedicated link
Layered Architecture of EDI
EDI semantic
layer
EDI Standard
layer
EDI transport
layer
Physical layer
Application level services
EDIFACT business form standards
ANSI X12 business form standards
Electronic mail
X.435, MIME
Point to Point
FTP, Telnet
WWW
HTTP
Dial up lines, Internet
Information flow without EDI
Buyer
Purchase
request
initiated in the
organization
Seller
Finance
department
Finance
department
Bill
Payment
Purchase
department
Inventory
and
warehousing
Order
delivery
Paper
based
mailroom
Paper
based
mailroom
Receiving
department
Shipping
department
Product
delivery
Order
confirm
Sales
department
Manufacturing
department
Information flow with EDI
Buyer
Purchase
request
initiated in the
organization
Seller
Payment
details
Purchase
department
Finance
department
Finance
department
EDI
capable
computer
Billing
details
Purchase
order
delivery
EDI
capable
computer
Sales
department
Shipping
department
Manufacturing
department
Automated
order
confirmation
Inventory
and
warehousing
Receiving
department
Product
delivery
EDI Process
Network
Vendor
Buyer
receive
send
send ack
receive ack
EDI software
•
•
•
•
•
Application software
Message translator
Routing manager
Communication handler
Shrink wrapped software available
that provides many EDI functions
Communication approach
• Dial up is entry level
• Companies internal networks limit
who you can interact with (VAN)
• Lots of competition between
companies
• Internet is an appealing alternative
Open EDI
• Using the internet
• Cost of transferring messages is
cheaper on the internet
• More cost effective movement of
large files
– supplement purchase orders with
product descriptions, graphics, video
clips, etc
EDI across the Internet
• FTP
– login ID and password required for all
trading partners
– directory names and files name
agreement
• E-mail
– more secure
– less administration
– may not be able to handle large
documents
– SMTP treats EDI as printable text (use
MIME)
Challenges
• Internet security
– use encryption and digital signatures
• Not all VANs have connection to the
internet
– may not have staff/expertise to switch
– MIME formatted EDI headers cannot be
interpreted by VANs
• SMTP only supports negative
delivery notifications
– use functional acknowledgment
transaction
Network Architecture
Internet
Service
Providers
On-Line
Services
vBNS
Backbone
Internet
Society
Internet
Registry
Regional
Network
Internet
Registrar
Regional
Network
Modem
Modem
Satellite
link
Router
Internet
Provider
T3 line
Network
Access
Point
Regional
Network
Router
Backbone
Router
Ethernet Network
T1 line
Network
Access
Point
THE OPEN SYSTEM
INTERCONNECTION
(OSI) MODEL
Application
Layer
Presentation
Layer
Logical Flow
Network
User
Transaction
Services
Provides application services, such as distributed database
access and document interchange, to network users
Transaction
Services
Presentation
Services
Formats data for different presentation media and
coordinates resource sharing
Presentation
Services
Data Flow
Control
Synchronizes flow between end-points, correlates exchanges
and group related data into indivisible units
Data Flow
Control
Transmission
Control
Paces data exchange to match end-point processing capacity
and Enciphers user data, if needed security
Transmission
Control
Network Layer
Path
Control
Routes data in “packets” between source and destination and
controls traffic and congestion in the network
Path
Control
Data Link Layer
Data Link
Control
Transmits data reliably between adjacent nodes all along
any route
Data Link
Control
Physical Layer
Physical
Control
Connects adjacent nodes physically and electrically
Physical
Control
Session Layer
Transport Layer
Node B
Network
User
Physical Flow
Node A
Communications Network
Architectures
ISP Service Categories
Web Hosting
Services
Dial-up
Internet
Access
Dedicated
Internet
Access
Managed
Router
Services
VPN
Services
Security
Services
Wholesale
transit
Services
Colocation
Provider
Basic Network
• Regardless of the size of the ISP
network, basic components are the
same
– access devices
– data forwarding network elements
(routers)
– information servers
ISP Size
• Small ISPs
– modem pools (access concentrator)
• 24 modems connected to a local exchange
carrier (LEC) via a T1 or primary rate ISDN
• Larger ISPs
– add more Points of Presence (POP)
– increase density of current POP
– POP is a location where the service
provider is allowed to install equipment
• may be owned by somebody else
Internet Components
Regional Point of
Presence
Major Point of
Presence
Residential Subscriber
Backbone
Modem
Pool
Router
Routers
Backbone
Data
Routers
• Hardware and/or software that
determines the next network point to
forward a packet of data
• Connected to at least two network
pathways
• Determines which pathway to route
each information packet
– based on understanding of the state of
the networks
Current Internet Network
Architecture
Very High Speed Backbone
(operated by MCI)
Backbone
Network
Access
Provider
California
(PacBell)
Chicago
(Ameritech)
New York
(Sprint)
Washington
(MFS)
Internet
Access
Provider
Sprint
AOL
UUNet
Local
Access
Provider
Local
Local
Local
Local
Providers Providers Providers Providers
Local
Providers
End users
MCI
Home
Customers
AT&T
Small
Bsinesses
PSI
Local
Providers
Large
Government
Businesses
Internet Topology
• Home Users dial into a local access
provider using a PC modem
– use twisted pair existing telephone lines
– relatively slow
– businesses may choose faster access
• ISDN (Integrated Digital Systems Network)
• T-1 lines (1.544 Mbps)
• T-3 lines (45 Mbps)
Internet Topology
• All lines routed to a local access
provider
– users switched through the direct
connect access provider to the closest
network access point (NAP)
• These access providers have
proprietary, high-speed nationwide
communication networks
– these are the local access points
– also called Points of Presence (POP)
– allow access to Internet with phone line
Internet Topology
– POPs necessary to reduce toll charges
– Established in major cities (local call for
users)
– Modem pools and network interfaces
convert analog dial-up signals from
user into digital for more efficient
transport to the backbone
• POPs connected by high speed
telephone circuits to central hubs
• Hubs are connected to high-capacity
network backbone
Hardware in a POP
• Server Platform
– powerful system for multiple users (Sun
Workstation)
• Networking Infrastructure
– routers, terminal servers, switches
– provides POP to the internet
• Leased telecommunication lines
– from a local telephone company
Hardware in a POP
• Modems
– batch of modems to allow users to
access the IAP
– racks of single or digital modems
Structure of a Point of Presence
National
Independent
Backbone
Internet
T3
ATM
Switch
28.8 Kbps
or ISDN
connections
Fast
ethernet
ISDN
terminal
server
Inside a typical
point of presence
Distribution
router
USENET
server
T3
T1 connections
to customers
T1
Terminal
Server
56K connections
to customers
Analog
modems
9.6, 14.4, 28.8
Kbps
Dial up Access Connectivity
Residential
Subscriber
Public
Switched
Telephone
Network
ISP
Point of
Presence
(POP)
Internet
Backbone
Modem
Modem
Voice Switch
Router
Dial up Access POP
Modem
Web
Cache
Residential Subscriber
Major
Point of
Presence
Backbone
Voice Switch
Residential Subscriber
Router
Public
Switched
Telephone
Network
Regional
Point of
Presences
Router
Router
Backbone
Modem
Router
Web
Cache
Web
Cache
ISP dial up POPS are similar
• Access concentrator
– device that connects several modems
into a single chassis
• Access concentrator connected to a
colocated router across a LAN within
the POP (ethernet hub)
• Router connected through telecom
carrier to the ISPs IP transit provider
(or upstream POP)
Digital Subscriber Access
• xDSL
– asymmetric (most common)
– symmetric
– very high speed
• Typical deployment
– 1.5 Mbs from ISP to customer
– 128Kbs back channel
• Similar to dial up
– connectivity with modem or NIC
– DSL modems connect to PC with
ethernet
Digital Subscriber Line
Access Multiplexer
ISP Point of
Presence
Modem
Residential Subscriber
DSL
Access
Multiplexer
Internet
Modem
Modem
Residential Subscriber
Voice Switch
Router
Network Infrastructure for
Electronic Commerce
• The Internet
Architecture
• World Wide Web
–Concept and
Architecture
–Protocol
–Gateway interfaces
–Web extensions
Information Superhighway
Infrastructure
I-way—the network infrastructure for electronic
commerce
Network
Access
Equipment
Local On-ramps
Global Information
Distribution
Networks
Telecom-based
infrastructure
Consumer/
business
premises
equipment
Cable TV-based
infrastructure
Wireless
infrastructure
Commercial on-line
infrastructure
Backbone
communications
and satellite
networks
Internet Access Providers
• Telco companies—long distance
telephone companies who
traditionally focus on large business
users and are now moving into
consumer access market (e.g. AT&T,
MCI, Sprint)
• Cable companies—access providers
for home users via cable modems.
May bundle Internet with other
services (e.g. Time Warner, TCI)
Internet Access Providers
• Online companies—companies that
package a range of information and
Internet access for a monthly fee via
local telephone number (e.g. America
Online, CompuServe, Microsoft
Network)
• National independents—for-profit
entities that offer connectivity
services nationwide or
internationally
Internet Access Providers
• Targets business users and other
smaller providers who do not have
resources to provide widespread
coverage (e.g. PSI, UUNET)
• Regional—nonprofit university
affiliated enterprises that forming
strategic alliances with larger players
(e.g. SURAnet, NEARnet).
Internet Access Providers
• Local service providers—small
businesses operate in one physical
location and offer services within a
single metropolitan area.
Internet Architectures
ISP Service Categories
Web Hosting
Services
Dial-up
Internet
Access
Dedicated
Internet
Access
Managed
Router
Services
VPN
Services
Security
Services
Wholesale
transit
Services
Colocation
Provider
Basic Network
• Regardless of the size of the ISP
network, basic components are the
same
– access devices
– data forwarding network elements
(routers)
– information servers
ISP Size
• Small ISPs
– modem pools (access concentrator)
• 24 modems connected to a local exchange
carrier (LEC) via a T1 or primary rate ISDN
• Larger ISPs
– add more Points of Presence (POP)
– increase density of current POP
– POP is a location where the service
provider is allowed to install equipment
• may be owned by somebody else
Internet Components
Regional Point of
Presence
Major Point of
Presence
Residential Subscriber
Backbone
Modem
Pool
Router
Routers
Backbone
Data
Dial up Access Connectivity
Residential
Subscriber
Public
Switched
Telephone
Network
ISP
Point of
Presence
(POP)
Internet
Backbone
Modem
Modem
Voice Switch
Router
Dial up Access POP
Modem
Web
Cache
Residential Subscriber
Major
Point of
Presence
Backbone
Voice Switch
Residential Subscriber
Router
Public
Switched
Telephone
Network
Regional
Point of
Presences
Router
Router
Backbone
Modem
Router
Web
Cache
Web
Cache
ISP dial up POPS are similar
• Access concentrator
– device that connects several modems
into a single chassis
• Access concentrator connected to a
colocated router across a LAN within
the POP (ethernet hub)
• Router connected through telecom
carrier to the ISPs IP transit provider
(or upstream POP)
Digital Subscriber Access
• xDSL
– asymmetric (most common)
– symmetric
– very high speed
• Typical deployment
– 1.5 Mbs from ISP to customer
– 128Kbs back channel
• Similar to dial up
– connectivity with modem or NIC
– DSL modems connect to PC with
ethernet
Digital Subscriber Line
Access Multiplexer
ISP Point of
Presence
Modem
Residential Subscriber
DSL
Access
Multiplexer
Internet
Modem
Modem
Residential Subscriber
Voice Switch
Router
Common Internet Access
Methods
Type of Internet Access
Protocol
Speed
Dial-up(shell account):
Easy and inexpensive, but
cannot use Netscape.
Terminal
9.6, 14.4
Emulation Kbps
Cost
$6-$20 / month,
unlimited usage
Dial-up IP: Full access to
SLIP, PPP
Internet, but more complex to
configure and set up
14.4 Kbps
28.8 Kbps
Digital dial-up (ISDN):
PPP
Not widely available, and has
problems with procurement
and installation.
64, 128 Kpbs $30-$300 / month
+ installation
1 cent/minute
Leased line: High-speed
dedicated link, but can be
expensive if not used
frequently
56 Kbps
1.544 Mbps
(T1)
IP
$20 / month for 20
hours, $1-$2 / hour
thereafter
$2500
$10K+$1500 /
month
The Web Enterprise
Extranet
Suppliers
Distributors
Enterprise
Banks
Intranet
Electronic
Storefront
Logistics
Provider
Business
Intelligence
• Knowledge
Management
• Internal
Communicati
on
• Project
Management
Customer
Services
Internet
Information
Dissemination
Components of the Web
Databases
Web Browser
TCP/IP
based network
(HTTP)
Web Clients
1. Browser establishes
connection with server.
2. Browser issues request
to server.
3. Server sends a
response (page or
graphics)
4. Both browser and
server disconnect and
the transaction ends.
CGI
Web Servers
(web pages)
HTML describes
the contents of
each Web page
Content
Software
applications
Common
Gateway
Interface (CGI)
CGI defines how
external
applications can
interact with Web
servers
Worldwide Web (WWW)
• The most popular Internet service
(since 1993)
• WWW documents are linked to other
documents by means of a
technology called “Hypertext”
• The Web essentially contains an
unlimited number of documents
using a variety of media.
• When browsing Web resources, you
decide how to navigate through the
documents.
Worldwide Web (WWW)
• Web functions: view multimedia
documents, download files, e-mail,
discussion groups, run programs
interactively, buy and sell goods and
services.
• Middleware that operates on top of
the Internet to support a community
of users and applications
Worldwide Web (WWW)
• WWW makes hypermedia available
on the Internet in what has evolved
into a global information system.
• Web users can access corporate
information by using Web gateways.
The World Wide Web
(WWW)
• Web access to non-Web resources is
provided through Web gateways
– Web access to relational databases is
provided through “relational gateways”
that serve as translators and mediators
between Web browsers and relational
database managers.
The World Wide Web
• Organizations can standardize on
Web browsers for end-user access to
all applications. The same Web
interface can be used for
applications that cross company,
industry and country boundaries.
• Java is a programming language
designed to work on the Web. Its
application components run on the
Web browser site, hence
implementing the first-tier C/S
applications.
Conceptual View of WWW
UNIX
Macintosh
Web Browser
(X Mosaic)
Web search
tools
HTTP
Web Browser
(Netscape)
PC
Web Browser
(Microsoft)
HTTP
HTTP
URL://http//seas.smu.edu/faculty.html
Web Site www.shoes.com
• Web server (program)
• HTML documents
• Gateway for Database Access
databases
Web Site cs.um.edu
• Web server (program)
• HTML documents
• (Faculty.html, courses.html)
Why is the Web appealing?
1. All Web applications and
technologies are standards-based =>
eliminate the need to port to multiple
platforms to reach new markets
2. Web technologies are
client/middleware/server applications
=>users can readily utilize
distributed computing resources
Why is the Web appealing?
=>minimize need for end users to
frequently upgrade existing
hardware, OS or network
infrastructures
3.New Web-based applications are
maturing quickly
=>Web technology may replace
functionality of many current
desktop and platform-centric
applications of today.
Key Concepts of the WWW
• Global hypertext publishing—a
seamless world in which all online
information are accessed and
retrieved in a consistent and simple
way.
• Universal readership—a universal
user interface can be used to read a
variety of documents.
Key Concepts of the WWW
• Client/server interaction; Web can
grow without any centralized control
• Web provides a way to interconnect
computers running different
operating systems and display
information created in different
media formats.
Protocol
• Greek; protocollon (leaf of paper
glued to a manuscript) is a special
set of rules for communicating
• Exist at several levels in a
telecommunications connection
• Often describe an industry or
international standard
Protocols
• Protocol stacks—a set of rules for
inter-computer communication that
has been agreed upon and
implemented by many vendors,
users and standard bodies.
• Two architectures: Open System
Interconnection (OSI) and
Transmission Control Protocol
(TCP).
Protocols
OSI
Application
Layer
Presentation
Layer
Application or
process Layer
Session Layer
Transport Layer
Hot-to-host
transport Layer
Network Layer
Internetwork (IP)
Data Link Layer
Network Interface
Physical Layer
Physical Layer
TCP
OSI Protocol Stack
Application
Layer
Application messages
Presentation
Layer
Encyphered or compressed
Session Layer
Session messages
Transport Layer
Multiple packets
Network Layer
Packets
Data Link Layer
Frames
Physical Layer
Bits
TCP/IP
• TCP; uses a set of rules for
exchanging messages with other
internet points at the information
packet level
• IP; uses a set of rules to send and
receive messages at the Internet
address level
• Others
– HTTP
– FTP
TCP/IP
• Basic communication language or
protocol of the Internet
• Also used for intranets and extranets
• Setup with direct access to the
Internet requires copy of TCP/IP
program
• Two layers
– TCP; manages the assembling of a
message or file into smaller packets
that are transmitted over the Internet
TCP/IP
– IP; handles the address part of each
packet so that it gets to the right
destination
• gateway computers on the network checks
address to see where to forward the
message
• packets re-assembled on the other end
• Uses the client/server model of
communication
TCP/IP
• Communication is primarily point to
point
• Connectionless
– freed network paths
TCP/IP
• Upper layer protocols often ties to
TCP/IP as a suite
– HTTP
– FTP
– SMTP
TCP Protocol Stack
FTP
HTTP
TELNET
SNMP
TCP
MBONE
UDP
IP
(ICMP, IGMP)
Internet Addressing
Physical layer
Physical wiring
Sender
01100101
10001101
11011000
01010111
Receiver
TCP/IP
TCP
126.119.6.4
IP packets
126.119.6.4
Checksum
Packet order
Destination
address
Sender address
Amount of time before discarding
126.119.6.4
01100101
10001101
11011000
01010111
WWW Middleware
• Web sites: provide the content that
is accessed by Web users. Usually
managed by content providers.
• Web server: a program (a server
process) that receives calls from
Web clients and retrieves Web pages
and/or receives information from
gateways.
WWW Middleware
• Web browsers: The graphical user
interfaces that clients use to wander
through the Web sites.
• Uniform Resource Locator (URL): A
string of characters that uniquely
identifies a resource. Used to locate
resources in WWW.
WWW Middleware
http://seas.smu.edu/faculty.html
HTTP
request
initiated
Name of machine
running the Web
server
Name of the file on the
machine cs.um.edu
WWW Middleware
• Hypertext Markup Language (HTML): a
language that tags the text files for display
at Web browsers
– Through HTML, users can flip through Web
documents in a manner similar to flipping
through a book or catalog.
• Hyperlinks: hypertext links that provide a
path from one document to another.
• Hypertext Transfer Protocol (HTTP):
application-level protocol designed for
Web users
– establishes connection with the Web server
specified in the URL, retrieves the document
and closes the connection.
Generic Web Gateway
Interfaces
Web Browsers
HTTP
Web
Site
Web Server
Web Content
(HTML Pages)
Web Gateway
Non-Web
Content
Web gateways bridge the gap between Web browsers and
the corporate applications and databases.
Types of Web gateways:
• Dedicated relational database gateway
• Common Gateway Interface (CGI)
• Java-based gateway
Standalone Server
A Dedicated Relational
Database Gateway
Web Browsers
Response 5
in HTML
Web
Site
1 Request
Web Server
4
1)
1
2)
SQL Gateway
3)
3
2
Relational Database Manager
4)
5)
A specialized standalone
server can be developed
to behave as a gateway.
Every call received by the
server performs a
gateway function:
Dedicated DB gateway
receive SQL calls from a
Web browser.
Sends SQL statements to
target databases.
Receives results of SQL
query.
Build HTML pages from
results.
Send results back to Web
browsers
CGI Gateways
• CGI gateway is a program that
resides on the Web server
• The program can be a script (e.g.
Perl script) or an executable program
(e.g. a C++ program)
• Hyperlinks to this program are
included in HTML documents
– When the user clinks on the hyperlink,
The gateway URL is passed to the Web
server which locates the program in the
/cgi-bin/ directory and executes it
– Results sent back to the Web browser.
CGI Gateways
Web Browsers
Results
Web
Site
Query
Web Server
CGI
Gateway
Single
Step
CGI
Gateway
Two
Step
Web Content
(HTML Pages)
Application
E.g. DBMS
CGI Gateways
HTML
Web page
Web
Browser
(5) User
receives reply
Web Server
(1) User enters
information
(2) Sends
message to
CGI
program
(4)
Construct
reply to user
CGI
program
CGI
program
3) Process
message
(May call other
programs)
Application
Common Gateway Interface
• Generic interface between serve and
gateway programs.
• Specifies how data are sent to and
returned from gateway programs.
• Sending:
– environment variables e.g.
REMOTE_ADDR, QUERY_STRING,
REMOTE_HOST etc.
– data from clients (from standard input)
Common Gateway Interface
• Returning:
– Results that the server can process
– I.e. A HTML Web page with in HTML
format.
– Server displays this Web page on the
Web browser, which the user reads.
CGI Program Construct
Directory where Perl is located
#!/usr/bin/perl
#program.pl -- name of program
May invoke another program to
break down the input string into
meaningful attributes and values <Read input from client>
Generate a reply HTML
Web page
Process data
:
:
print “Content-type: text/html\n\n”;
<HTML Web page codes>
Java-Based Gateway
Web Browser
(Java Compliant)
Applications
Java Applets
Java
Applets
Web
Site
Request
Web Server
Java Powered
Pages
• Gateway distributes
code of the target
application and sends it
to the Web client where
it executes.
• Access to remote
application and
databases can be
invoked indirectly from
the browser.
Example:
Java applet asks the
user to query and sends
it to a remote
application or database.
Java and Java Applets
• Java is an object-oriented
programming language similar to
C++ developed by Sun Microsystem.
• Java supports user interactions with
Web pages.
• Java applets are small Java
programs embedded in Web pages
Java and Java Applets
• These Java Web pages (along with
Java applets) are downloaded to the
Web client and make the Web
browsers a powerful tool by enabling
user interactions.
• A Java application is a complete
standalone application that uses text
input and output
Java and Java Applets
• Java applets are not standalone
applications and run as part of a
Java-enabled browser (e.g. Hot
Java).
• Clients need a Java-enabled browser
to run Java-powered pages.
Examples: HotJava, Netscape 2.0
and higher
Java Characteristics
•
•
•
•
•
Simplicity
Object Orientation
Distributed
Robust
Architectural
Neutral
•
•
•
•
•
Portable
Interpreted
High performance
Multithreaded
Dynamic
Advantages:
• Network traffic reduction -- Java applets execute on the
client side and thus do not suffer from the issues of network
traffic between the Web client and Web server.
• Plug-and-play Java applets -- Java applets once built can run
on many machines. They also have access to a wide range
of libraries.
Downloading and running Java
applets
The Java browser load process
consists of the following steps:
• User selects and HTML page.
• Browser locates the page and starts
loading it. While loading, it starts to
format text.
• It loads graphics if indicated by IMG
or FIG tags in HTML.
Downloading and running Java
applets
• Java applets are indicated by an
APPLET tag
• Example
<APPLET CODE=myapplet.class
WIDTH=100 HEIGHT=100>
</APPLET>
Downloading and running Java
applets
• Browser loads the indicated class
and other needed classes.
• Java-”enabled” browsers also keep
local classes that may be used by the
applets.
• After the applet has been loaded, the
browser asks it to initialize itself
(init() method) and draw a display
area that is used for input/output.
Multimedia Web Extensions
• Virtual Reality Modeling Language
(VRML)
– An object-oriented 3-D protocol that
enables the creation of interactive 3-D
environments on the Internet.
– Applications: virtual reality applications
like molecular modeling, flight
simulation, computer-aided product
design
Multimedia Web Extensions
• RealAudio
– Streaming audio—sound files are
played as they are being downloaded.
– Applications: live and rebroadcast
music and audio
– Streaming video—towards video
online?
• Internet/Web-based telephony
– E.g. Cool Talk—communication across
the Internet with full duplex sound.
– Applications: cheap phone calls,
shopping, customer service over WWW,
Communications Network
Architectures
THE OPEN SYSTEM
INTERCONNECTION
(OSI) MODEL
Application
Layer
Presentation
Layer
Logical Flow
Network
User
Transaction
Services
Provides application services, such as distributed database
access and document interchange, to network users
Transaction
Services
Presentation
Services
Formats data for different presentation media and
coordinates resource sharing
Presentation
Services
Data Flow
Control
Synchronizes flow between end-points, correlates exchanges
and group related data into indivisible units
Data Flow
Control
Transmission
Control
Paces data exchange to match end-point processing capacity
and Enciphers user data, if needed security
Transmission
Control
Network Layer
Path
Control
Routes data in “packets” between source and destination and
controls traffic and congestion in the network
Path
Control
Data Link Layer
Data Link
Control
Transmits data reliably between adjacent nodes all along
any route
Data Link
Control
Physical Layer
Physical
Control
Connects adjacent nodes physically and electrically
Physical
Control
Session Layer
Transport Layer
Node B
Network
User
Physical Flow
Node A
Communications network architectures. The OSI model is recognized as an
international standard. IBM’s SNA is the leading network architecture for
mainframe-based telecommunications networks.
E-Commerce Architectures
Electronic Commerce
Architecture
Client Browser
WWW Server Functions 3rd Party Service
Local or
company
specific data
Information
Retrieval
Digital
library of
document/
data servers
Mosaic/WWW
browser
Data and
transaction
management
Third party
information
processing
tools/services
Browser
extensions
Secure
messaging
Electronic
payment
servers
A typical E-Commerce architecture
Back End
Relational
Database
Web/Commerce Servers
Document
Management
Payment
System
Imaging
Proprietary
ERP
Web Clients
Web Clients
• Web client (perspective of merchant)
• Browser (perspective of customer)
• Examples
– Mosaic
– Netscape Navigator
– Internet Explorer
Web Server/Commerce
Server
Web/Commerce Servers
Commerce
Server S/W
Web
Server S/W
HTTP
TCP/IP
Web Clients
Web Server Software
SITE SERVER COMMERCE
SITE SERVER
FRONT PAGE
OPTION PACK/IIS
SERVICE PACK 3
NT SERVER
Back End Servers
Back End
Web/Commerce Servers
Web Clients
Back End Systems
•
•
•
•
SQL
DB2
Oracle
ERP
– PeopleSoft
– SAP
Clustered Servers
Web/Commerce
Servers
Web Clients
Router
Clustering
Real-time Updates
Replicated Servers
Web/Commerce
Servers
Web Clients
Router
Replication
Scheduled Updates
Common Internet Access
Methods
• Dial-up
– Easy and inexpensive
– Protocol; terminal emulation
– Speed; 9.6, 14.4 Kbps
• Dial-up IP
– full access to internet but more complex
to configure and setup
– Protocol; SLIP, PPP
– Speed 14.4, 28.8 Kbps
Common Internet Access
Methods
• Digital dial-up (ISDN)
– procurement and installation
– Protocol; PPP
– Speed; 64, 128 Kbps
• Leased Line
– high speed dedicated link
– Protocol; IP
– Speed; 56 Kbps, 1.544 Mbps (T1)
Point-to-Point Protocol
• Protocol for communication between
two computers using a serial
interface
– PC connected by phone line to a server
– ISP provides customer with PPP
• server responds to requests
• pass request on to internet
• forwards requested Internet responses back
to you
• Uses IP
• Layer 2 (data link layer)
Point-to-Point Protocol
• Packages PC’s TCP/IP packets and
forwards them to the server where
they can then be put on the Internet
• Full duplex protocol
– twisted pair
– fiber optic
– satellite
• High Speed Data Link Control (HDLC)
for packet encapsulation
Point-to-Point Protocol
• Can handle asynchronous as well as
synchronous communication
• Can share the line with other users
• Generally preferred over SLIP (Serial
Line Internet Protocol)
Another Configuration
Front End
Back-end
databases
Web/Commerce
Servers
Internet
Software
HTTP
Protocols
TCP/IP
Router
Internal Credit
Verification
System
Internet
Protocols
TCP/IP
External Web
Clients
Replication
Internal Web
Clients
Firewall
A Typical Configuration
Front End
Back-end
databases
Web/Commerce
Servers
Internet
Software
HTTP
Protocols
TCP/IP
Router
Internal Credit
Verification
System
Internet
Protocols
TCP/IP
Internal Web
Clients
External Web
Clients
Firewall
Merchant Server - Physical
View
Merchant Server
Financial
Network
Internet
Buyer
with
Browser
Catalog
and order
Database
Merchant Server - Logical
View
Catalog
Data
Order
Data
Catalog Page
Static Content
Generation
Web Server
Credit Card
Order
Capture
Forms
Secure Electronic Transaction
(SET) Architecture
Merchant Server
with SET module
Interchange
Network
(mastercard,
Visa, etc
Internet
Buyer with browser
and SET wallet
SET
payment
gateway
Open Market Commerce
Architecture: Physical View
Catalog servers
with secure link
Financial
Network
Internet
Shared
transaction
server
Buyer with browser
Shared Transaction
Engine
Customer
Data
Order
Data
Payment
Data
Data Management
Catalog Server
Catalog DB
(Items,
Pricing)
Catalog Application
SecureLink
Web Server
Customer
Management
(Registration,
Profiles)
Order
Capture
(Order
Form)
Order
Completion
(Tax,
shipping)
Payment
Processing
(SET,
Purchase
Order)
Web Server
Web Server
Internet
Fulfillment
and
Customer
Service
Open Buying on the Internet
(OBI) Business Purchasing
Process
Browse
Request
Approve
Fill
Receive
Pay
OBI Architecture
Catalog Browse/Buy
Order Status Query
Requisitioner
Profile Information,
Pending orders
View/Update
Buying
Organization
Order creation
and approval
Payment Validation
Supplier
Corporation
Payment Vehicle
Authorization
Clearance
Payment
Authority
OBI Transaction Flow
Buyer home page
(with list of suppliers)
Seller catalog
1. Requisitioner
selects supplier
2. Requisitioner browses
catalog and orders
Requisitioner
5. Buyer approves
requisitioners order
3. Catalog routes
order to OBI server
4. Seller sends OBI
request to buyer
Buyer OBI
server
(approvals, etc)
6. Buyer sends
complete OBI order to seller
7. Seller routes order
for fulfillment and
payment
Seller
OBI server
Seller
fulfillment
systems
Intranets and Extranets
The Web Enterprise
Extranet
Suppliers
Distributors
Enterprise
Banks
Intranet
Electronic
Storefront
Logistics
Provider
Business
Intelligence
• Knowledge
Management
• Internal
Communicati
on
• Project
Management
Customer
Services
Internet
Information
Dissemination
Intranets
• A private network that is contained
within an enterprise
• May consist of many interlinked local
area networks and also use leased
lines in the wide area network
• Typically includes connections
through one or more gateway
computers to the outside Internet
Intranets
• The main purpose of an intranet is to
share company information and
computing resources among
employees
• An intranet can also be used to
facilitate working in groups and for
teleconferences.
Intranets
• An intranet uses TCP/IP, HTTP, and
other Internet protocols and in
general looks like a private version of
the Internet
• Can send private messages through
the public network using tunneling
– public network with special
encryption/decryption and other
security safeguards to connect one part
of the intranet to another
Intranets
• Larger companies allow users within
their intranet to access the public
Internet through firewall servers
– that have the ability to screen
messages in both directions so that
company security is maintained
• When part of an intranet is made
accessible to customers, partners,
suppliers, or others outside the
company, that part becomes part of
an extranet
Internet vs. Intranet
Internet
• A large collection of TCP/IP networks that
are tied together through network
interconnectivity such as routers and
gateways.
• Computers on the public Internet have
publicly known Internet Protocol (IP)
addresses that are used to exchange
information over the public Internet.
Internet vs. Intranet
Intranet
• TCP/IP networks used by corporations for
their own business, especially by
exploiting Web technologies.
• Use the same technology as the public
Internet.
• Any applications and services that are
available on the public Internet are also
available on the Intranets.
Intranet Benefits and
Drawbacks
Benefits
• Easy to publish internally
• Low cost since most organizations already
have TCP/IP networks.
• Corporate users can easily access
information on internal Web sites.
• Low maintenance and easy upgrading since
information resides in only one place—the
Web server
• Easy to scale the computing resources
upwards or downwards.
Intranet Benefits and
Drawbacks
• Easy software distribution through Web
browsers.
Drawbacks
• Collaborative applications for Intranets are
not as powerful as those offered by
traditional groupware.
• Short-term risk since Web programming
technology is still relatively new.
• Less back-end integration since
applications are separate unlike
groupware.
Intranet Architecture
Corporate Intranet
Clients
Legacy
systems
Public/
External
WWW
Users
Firewall
Intranet
Databases
E-mail
servers
Web
servers
Extranet
• An extranet is a private network that
uses the Internet protocols and the
public telecommunication system to
securely share part of a business's
information or operations with
suppliers, vendors, partners,
customers, or other businesses
• An extranet can be viewed as part of
a company's intranet that is extended
to users outside the company
Extranet
• An intranet that is partially
accessible to authorized outsiders
• Provides various levels of
accessibility to outsiders
– intranet resides behind a firewall and is
accessible only to people who are
members of the same company or
organization
• Must have a valid username and
password, and your identity
determines which parts of the
extranet you can view.
Extranet
• It has also been described as a "state
of mind" in which the Internet is
perceived as a way to do business
with other companies as well as to
sell products to customers
• The same benefits that HTML, HTTP,
SMTP, and other Internet
technologies have brought to the
Internet and to corporate intranets
now seem designed to accelerate
business between businesses
Extranet
• An extranet requires security and
privacy. These require firewall server
management, the issuance and use
of digital certificates or similar
means of user authentication,
encryption of messages, and the use
of virtual private networks (VPNs)
that tunnel through the public
network
Extranet
• Companies can use an extranet to:
– Exchange large volumes of data using
Electronic Data Interchange (EDI)
– Share product catalogs exclusively with
wholesalers or those "in the trade"
– Collaborate with other companies on
joint development efforts
– Jointly develop and use training
programs with other companies
Extranet
– Provide or access services provided by
one company to a group of other
companies, such as an online banking
application managed by one company
on behalf of affiliated banks
– Share news of common interest
exclusively with partner companies
Extranet
• An extension of an enterprise’s
Intranet to its business partners.
• Benefits:
– Leverage existing investment in
technology since most companies
already have their documents online
and Internet access.
– Extranet applications developed to
Internet standards are virtually
guaranteed to work with Web browsers
Extranet
– Extranet applications can be
customized to individual partners.
Furthermore, the applications are
accessible on a 24-hour basis,
improving customer satisfaction.
• Issues:
– Security and access privileges
– Web site management and maintenance
Extranet Architecture
Enterprise
intranet
Banks
N
Contractors
N
Email
Broadcast
Discussion
room
rd
3 party
cybermediary
IS
Search
engine
N
Product
catalog
extranet
N
Suppliers
N
Manufacturer
N
Distributor
N
Retailers
Purchasing
system
Legend
Intranet
Extranet
Internet
Web
browser
Firewall
Firewall
servers
N
Product Info
Purchasing
System
Chat
rooms
Direct-toconsumer
Virtual
community
N
N
N
Consumer
Consumer
Consumer
Internet, Intranet, Extranet
• Internet refers to outward-facing
systems, with little or no connection
to any other internal systems
• The Internet is the public, global
network of networks which is based
on the Internet Protocol (IP) and
related standards
• Designed to provide a standard
means of interconnecting networks
(any system can communicate with
any other system)
Internet, Intranet, Extranet
• It operates as a confederated
network of networks (an "internet"),
and offers universal accessibility
Internet, Intranet, Extranet
• Intranet refers to inward-facing or
staff-facing systems
• A private application of the same
internetworking technology,
software, and applications within a
private network, for use within an
enterprise
Internet, Intranet, Extranet
• May be entirely disconnected from
the public Internet
– usually linked to it and protected from
unauthorized access by security firewall
systems
Internet, Intranet, Extranet
• An intranet has two fundamental
functions
– provide secure, customized access to
relevant, up-to-date information found
in transaction systems
– let users act on that information by
managing how it flows through process
systems
Internet, Intranet, Extranet
• An extranet is a use of
Internet/intranet technology to serve
an extended enterprise, including
defined sets of customers or
suppliers or other partners
• Typically behind a firewall, just as an
intranet usually is
• Closed to the public (a "closed user
group"), but is open to the selected
partners, unlike a pure intranet
Internet, Intranet, Extranet
• More loosely, the term may apply to
mixtures of open and closed
networks.
• Extranet refers to the marriage of
these two otherwise separate
systems into a single, seamless
system — a market-facing system.
IBM’s Ten Success Factors
for E-Business
• 1. E-business is as much about
business vision as technology
• 2. Key to a successful E-Business
transition is making your E-Business
priorities the same as your business
priorities
• 3. When you move to E-Business, it
pays to move quickly
• It pays to integrate E-Business with
your core operations from the start
IBM’s Ten Success Factors
for E-Business
• 5. Scalability, availability, and
security are not optional
• 6. Customer knowledge is everything
on the web
• 7. The key to transforming any major
process is to identify all the
subprocess
• 8. It pays to overbuild for traffic you
do not expect
IBM’s Ten Success Factors
for E-Business
• 9. A vital component of E-Business is
a way to manage the performance of
all your systems, networks, and
applications - as a single enterprise
• 10. Plan for change - tomorrow will
be different
So What is
Distributed
Computing?
Distributed Computing
• Computing is said to be "distributed"
when the computer programming and
data that computers work on are spread
out over more than one computer, usually
over a network
• Computing prior to low-cost computer
power on the desktop, was organized in
centralized "glass houses" (so-called
because the computers were often shown
to visitors through picture windows)
Distributed Computing
• Modern enterprises are using a mix
of desktop workstations, local area
network servers, regional servers,
Web servers, and other servers
Distributed Computing
• A popular trend has been clientserver computing which is simply the
view that a client computer can
provide certain capabilities for a user
and request others from other
computers that provide services for
the clients
– (The Web's HTTP protocol is an
example of this idea.)
Client/Server Computing
What is Client/Server
Computing
The client–server model consists of three parts:
• client - the active component that initiates a request
• server - the passive component that returns a service
• network - the media that enable the transmission of
requests and services
Server /Client
Client
Server
What are the Models of
Client/Server Computing?
• The key is the leverage of
computing power between
Clients and the Server
 How much work or how many functions are to be
handled by the client versus its server
Major Components in
Client/Server
• User Interface (I/O functions - Thin
Client, WWW, Phone)
User Interface
(e.g., Browser, I/O routines)
Functional Process (Business Rules)
Functional Obj.
(e.g., Stored procedures/Triggers)
DBMS (for data access and retrievals, networking, services)
Data Mgmt
(e.g., DB2, Oracle,
SQL/Server)
Major Models for Client/Server
Three-Tier Model
• Client requests its service via some
pre-compiled modules (COM) to
interact with data access software on
the server
Client
Agent
(COM)
Server
Component Object Module
(e.g., precompiled stored procedures)
3 Tier Client/Server
“Desktop” - Compound Documents, Controls, Scripting
H
T
T
P
C
O
M
Mid-Tier - HTTP, Biz Objects, Active Server Pages, Scripting
C
O
M
SNA
etc...
CORBA
Third-Tier - Databases, Legacy Data
Three-Tier Client/Server
Model Data Mgmt
Communication
Network
DB Server
Client
Functions
User
Interface
(e.g.,
Browsers)
Function Server
A New Trend in Object-oriented
Client/Server - N-tier Model
N-tier Architecture
First tier
Client Interface
2nd-tier
Business COM
3rd-tier
Business COM
x-tier
Business COM
Database Server
Mail Server
Gateway Server
DNS Server
Back-end-tier
System Server
Distributed Computing
• Most popular distributed object
paradigms
– Common Object Request Broker
Architecture (CORBA)
– Distributed Component Object Model
(DCOM)
– Java/Remote Method Invocation
(Java/RMI)
CORBA and ORBs
CORBA
• Common Object Request Broker
Architecture
• Brokers requests for services from
objects that may reside elsewhere on
a network
• Provides location independence
• Provides vendor and language
interoperability
CORBA
• Everything in the CORBA
architecture depends on an Object
Request Broker (ORB)
– acts as a central Object Bus over which
each CORBA object interacts
transparently with other CORBA objects
located either locally or remotely
CORBA
• Since CORBA is just a specification,
it can be used on diverse operating
system platform
– mainframes
– UNIX boxes
– Windows machines
– handheld devices
• As long as there is an ORB
implementation for that platform
CORBA Architecture
• Object Request Broker (ORB) is
the most important component
• Object Services are the low-level
services that must be available
on all platforms in a distributed
system (e.g., lifecycle)
CORBA Architecture
• Common Facilities are the
commonly-found services in
particular distributed systems (e.g.,
email, print queuing)
• Application Objects are the highlevel applications themselves (e.g.,
spreadsheets, word processors,
programmable controllers)
CORBA Architecture
CORBA
Applications
CORBA
Domains
CORBA ORB
CORBA Services
CORBA
Facilities
Object Request Broker
• A CORBA Object Request Broker
(ORB) is the middleware that
establishes the client-server
relationship between objects
• Using an ORB, a client object can
invoke a method on a server object
that can be on the same machine or
across a network
Object Request Broker
• The ORB intercepts the call and finds
an object that can implement the
request, pass it the parameters,
invoke its method, and return the
results
• CORBA, like SQL, provides both
static and dynamic interfaces to its
services
Object Request Broker
• The client does not have to know the
object's location, its programming
language, its operating system, or
any other system aspects that are
not part of an object's interface
• Also, the client and server roles are
dynamic: an object on the ORB can
act as either client or server,
depending on the occasion
Communicating via ORBs
Local Host
Remote Host
Java
Interpreter
or Browser
Request
Request
Object
Implementation
Client
Applet
ORB
Distributed Computing with
CORBA
• The client application does not need
to know whether the object resides
on the same computer or on a
remote computer elsewhere on the
network
• The client application needs to know
only two pieces of information
– the object's name
– how to use the object's interface
Distributed Computing with
CORBA
• The ORB takes care of the details
– locating the object
– routing the request
– returning the result
Features and Benefits
• Each object encapsulates the details
of its inner workings and presents a
well-defined interface, reducing
application complexity
• The CORBA approach also reduces
development costs, because once an
object is implemented and tested, it
can be used over and over again
Features and Benefits
• CORBA's platform independence lets
you run and invoke the object from
any platform; you can run an object
from the platform that makes the
most sense for that object
• CORBA's language independence
lets you reuse existing code and
leverage your existing programming
skills
Features and Benefits
• CORBA is based on an open,
published specification
• Implemented on and supported by
numerous hardware and operating
system platforms
• CORBA Java objects are portable
– build objects on one platform and
deploy them on any other supported
platform
Features and Benefits
• Interoperability. CORBA objects are
fully interoperable because they
communicate using the Internet
Inter-ORB Protocol (IIOP)
• Software bridges enable
communications between CORBA
objects and objects developed using
Microsoft's DCOM technology
Features and Benefits
• Modularity. CORBA objects interact
via interfaces
– developers can modify objects without
breaking other parts of the application
– Changing an object's implementation
does not affect other objects or
applications because that object's
interface stays the same
Features and Benefits
• Compatibility. CORBA protects your
investment in existing systems
– You can encapsulate a legacy
application, module, or entry point in a
CORBA IDL wrapper that defines an
interface to the legacy code
• Security. CORBA provides security
features such as encryption,
authentication, and authorization to
protect data and to control user
access to objects and their services
CORBA Environment
Source: Netscape
CORBA in a Three Tier
Architecture
Source: Netscape
Example
• Parcel-tracking application
• Suppose an Internet user wants to
track delivery of a package
• From a browser, the user enters a
URL that points to the delivery
company's Web server
Source: Netscape
Example
• The server uses HTTP to send a Web
page to the user
– that page contains an embedded Java
applet, which is the client component of
the parcel-tracking system
• So far, nothing is different from a
traditional HTTP Web transaction
Example
• Next, the user enters a parceltracking number into the appropriate
field in the Java applet
• Using the client-side ORB, the applet
then generates and sends an IIOP
message across the network, looking
for a specifically-named server
object that can obtain the status of
the parcel
Example
• The ORB on the server with the
appropriate parcel-tracking object
picks up the message and invokes
the object's status-finding method
• Through the server ORB, the object
then generates another IIOP
message looking for an object on a
legacy system that contains all the
parcel company's data
Example
• Upon obtaining the last request
through its ORB, the mainframe
containing the data-tracking object
determines that status of the parcel
from its database
• The mainframe returns an IIOP
message with the information to the
server object
Example
• The server then routes the
information-again with IIOP and the
ORBs-to the Java applet running on
the client, which displays the results
to the user
Example
Source: Netscape
COM
• COM (Component Object Model) is
Microsoft's framework for developing
and supporting program component
objects
• It is aimed at providing similar
capabilities to those defined in
CORBA
COM
• COM provides the underlying
services of interface negotiation, life
cycle management (determining
when an object can be removed from
a system), licensing, and event
services (putting one object into
service as the result of an event that
has happened to another object)
• COM includes COM+, DCOM, and
ActiveX interfaces and programming
tools
COM Principles
• Rigorous Encapsulation
– Black box -- no leakage of implementation
details
– All object manipulation through strict
interfaces
• Polymorphism
IUnknown
– via multiple interfaces per class
IDispatch
– “Discoverable”: QueryInterface
IRobot
COM
Object
COM Architecture
Client
COM
run time
Security
provider
COM
run time
Security
provider
RPC
Inprocess
Protocol stack
LPC
Component
RPC
Protocol stack
Local
DCOM networkprotocol
Source: Microsoft
Remote
COM Runtime Architecture
Flexible and extensible
Pluggable Transports
Proxy
TCP, UDP
SPX,IPX
Net BUI
HTTP
“Falcon”
COM Runtime
COM
Client
Server Machine
COM Runtime
Client Machine
Other
Component
Source: Microsoft
Component

The COM Architecture
A scalable programming model
In the same
process
Client
Component


Client Process
On the same
machine


Fast, direct
function calls
Client
COM
Component
Fast, secure IPC
Across machines

Server Process
Secure, reliable
and flexible
DCE-RPC based
DCOM protocol
Client
Server Machine
Client Machine
DCE
COM RPC COM
Source: Microsoft
Component
DCOM
• DCOM which is often called 'COM on the
wire', supports remoting objects
• A DCOM server is a body of code that is
capable of serving up objects of a
particular type at runtime
• DCOM server components can be written
in diverse programming languages like
C++, Java, Object Pascal (Delphi), Visual
Basic and even COBOL
DCOM
• As long as a platform supports COM
services, DCOM can be used on that
platform
• DCOM is now heavily used on the
Windows platform
COM/DCOM
Lets ActiveX components run anywhere
Client
Server
COM
COM
Object running
on client
Remote object on
any server
Object running
on client
Source: Microsoft
COM and DCOM
Sun Solaris (Sparc) 2.5
HP/UX
COM
COM
RC
COM
Client
DCOM
Q3’97
Q4’97
Digital Unix 4.0 (Alpha)
RC
COM
Q3’97
Digital Open VMS
IBM MVS 5.2.2 (OS390)
Siemens Nixdorf SINIX
COM
COM
Q1’98
IBM OS/400
COM
H1’98
H1’98
Linux 2.0 (Intel)
H1’98
IBM AIX
COM
COM
BETA
COM
Q4’97
SCO UnixWare
H1’98
Source: Microsoft
COM
H1’98
Architecture Overview
Containers
ActiveX documents
Internet Explorer
ActiveX
HTMLcontrols
Windows
VRML Shell
HTML
VRML
RealAudio
Office
Binder MPEG
Word
Shockwave ODBC
Visio
Mosaic
ActiveX
scripting
MicroGrafx
Services
URL resolution
HTTP, FTP
Hyperlinking
History
Favorites
Visual Basic
Basic
Visual
Script
Script
Code download
JavaScript
and security
REXX
PERL
COM+
• COM+ is an extension of COM
• COM+ is both an object-oriented
programming architecture and a set of
operating system service
• It adds to COM a new set of system
services for application components while
they are running, such as notifying them
of significant events or ensuring they are
authorized to run
COM+
• COM+ is intended to provide a model
that makes it relatively easy to create
business applications that work well
with the Microsoft Transaction Server
(MTS) in a Windows NT system
COM+
• It is viewed as Microsoft's answer to
the Sun Microsystems-IBM-Oracle
approach known as Enterprise
JavaBeans (EJB)
• Among the services provided by
COM+ are:
– An event registry that allows
components to publish the possibility of
an event and other components to
subscribe to be notified when the event
takes place
COM+
– The interception of designated system
requests for the purpose of ensuring
security
– The queueing of asynchronously
received requests for a service
Technology Scenario
COM+
MTS
COM
COM+ Services:
Events
Security
Load
Balancing
Queued
Components
In Memory
Database
Compensating
COM+Resource
Manager
caring, sharing
Administration
A
environment for your
components
MTS Services:
Transactions
Resource Pooling
Security
Administration
The Model
Tools Support
Multi-Language
Discovery (QI)