1C.WattersFeb 2001

Web Architectures

Designing for the Web

multi-multi-multi-multi-multi

Multi-client – PC, Mac, Unix, wireless, …Multi-server-platform – PC, Mac, Unix, watch,…Multi-tier – layers of software componentsMulti-threaded – concurrent processingMulti-component – CORBA, COM, javabeans,…Multi-database – Oracle, Ingres, Access, …Multi-cultural – North American, European, African, ….

Objectives

Examine current web 3-tier client/server architectures

Look at some basic E-commerce architectures

Client-Server model and Tiered Architectures

Late 1980’s

Replace centralized mainframe architectures

1-Tier Architecture Processing(a)

MainMainFrame

File Server Configuration(1-Tier (b))

FileServer Files

1.Ask for file2.File

3.Process

4. Return File

Client-Server Architectures

Provide responses rather than file downloads for local processing

Message basedServes many more users

simultaneouslyTiers

2-tier 3-tier N-tier or multi-tier

Client/Server Processing

Client

Server

Data

1.request

2.Process request

3.response

2-Tiers

Middle Tier

Implementation Strategies TP monitors (transaction processing monitors) Message servers Application servers ORB (CORBA) Object Request Broker

Functions Queuing Application execution caching

Why bother?

Scalable Number of users Number of transactions

Flexible Drop applications onto different

servers Keep sophisticated applications

independent of server

Fatness in Clients

Where do you want the processing ??

Fat client Application and processing on client Download application and every update

Thin client Application and processing on server More traffic

Some Design Examples

Shopping cartB2CB2B

Shopping Cart (B2C)Client Tier (applet/javascript)

Validate format of credit card numberDo “what-if” calculations

Middle Tier/ Middleware (java/perl)Create catalog for displayMake purchase

Data Tier (Oracle, Ingres, Access, etc)Query inventory for selection of itemsUpdate inventory after sale

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B2B Architecture

B2C E-commerce

Consumers

B2B E-Commerce

BusinessCustomers

Supplier’sProducts Catalog

Customer’sOrder Information

Supplier’sElectronic Mall

As a 3-Tier Architecture

Supplier GUI Customer GUI

Make quote Order Create Catalog

TakeOrder

Oracle

UI

Tier

App

Tier

Data

Tier

Internet based EDI

InternetWeb

server

EDIserver

database

database

EDI legacy applications

Browser

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Peer-to-peer

Each party has the same capabilitiesTypically each party is a client-serverExamples Napster – MP3 file sharing Gnutella – file sharing IBM APPN

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Peer-to-peer on the Internet

Transient internet network in which users use the same application to communicate and share access to their hard drivesAdvantages Don’t have to move files to central

server

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How to make this work on the Internet

Create an applicationEverybody downloads the applicationExecute applicationsConnections Gnutella model – enter known IP address Napster model – enter Napster IP

address

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Napster and Gnutella

MP3Central serverServer collects dataServer as switch for downloads

Other filesNo central serverDirect IP connectionsHorizon of 1000

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GarageSale Samples Client 1.1

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RECAP

Internet activity is client/server based

MultiTier architectures provide flexibility

Peer-to-peer is here!