© Dr. Lixin Tao, 2000 1

Application Service Provider Model: Perspectives and Challenges

Lixin TaoDept. of Computer Science

Pace Universityltao@pace.edu

© Dr. Lixin Tao, 2000 2

Contents

ASP as service-based computing modelAdvantages of ASP computingASP challengesASP supporting technologiesASP challengesASP as first step towards network-centric computing and networked economy

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Two Industry Commercial Models

An application consumes resources to provide servicesThe end-users only care about servicesTwo major commercial models:

Service-basedResource/application based

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Two Industry Commercial Models ...

Service-based industries use comprehensive resource/service delivery network and application hosting; no expertise is needed from end-usersResource/application based model sells resources (generators) and applications, and end-users need expertise to turn resources and applications to services

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Resource/Application Based Model

Computer industry mainly sellhardware: resource generatorsoftware licenses

Users need to maintain infrastructureinstall and maintain applications

The model lacksresource sharingexpertise pooling

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Service Based Model

The model is based on standardization End-users don't need expertise in turning resources to servicesTelecommunications sell resources and services

Network bandwidthValue-added services

– Caller-ID, directory service, …

Utility industries mainly sell resources

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Service Based Model …The model enjoys

Resource sharingAmortization of infrastructure costExpertise poolingValue-added servicesService quality controlRich cost modelsStandardization of resources and main services

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Internet Enables Service-Based Computing Industry

Internet is becoming global service delivery networkWeb browsers become universal GUIInternet makes global distributed system integration possibleComponent technologies become key to control the complexities of distributed applications

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Application Service Provider Model

Most ISPs have become application service providersE-Commerce web sites are also examples of ASPASP is based on

Application hostingThin client and component technologiesComprehensive service/data delivery network

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ASP Model …ASP represents the beginning of commercially delivering computing as servicesThe ASP market is projected to grow rapidly over the next 3-5 years, from a very small base to over $20 billion in 2003, yielding a compound annual growth in excess of 80%ASP is still young, it needs significant breakthroughs in

network infrastructureComputing technologiesRental-based cost models and financial services

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Benefits of ASP

To service providersNo distribution costsNo user installationFewer illicit copyingInstant upgradesConsistent user baseUsage monitoringPotential constant revenue stream

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Benefits of ASP …

To usersLimitless choicesNo installation hassleNo compatibility issuesNo support overheadReduced downtime

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Benefits of ASP … Benefits of ASP

To investorsA high percentage of predictable, recurring revenue through competitive ASP operationsLeverage generated from a one-to-many solution modelAbility to sell high-margin, value-added services into the customer base

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Major Difficulties of ASP

Difficulty in securing client dataLimited performance due to limited bandwidth of the InternetLack of standardization of services

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ASP Supporting Technologies

ASP generalizes distributed computing to distributed system integrationASP enabling technologies turn existing client/server applications to ASP ones with minimal investment and inferior performance

Windows 2000 Terminal Services (WTS)Citrix

Component technologies are main tools to control complexities of ASP applications

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Objects vs Components

Object reuse based on inheritance implies the availability of application module source code Object reuse implies language dependencyMost companies don't like to release source codeA component is a binary module supporting a set a special properties for binary system integration

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A Reference Model for Distributed Components

Binary code integrationUniversal referenceNetwork interoperabilityIntrospectionCustomizabilityToolability

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Component Support System

NamingTradingLife cyclePersistenceEventTransaction……

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Major Component TechnologiesCORBA

Supported by industry consortium OMG representing over 800 companiesSupports heterogeneous platformsSupports all of our component properties except customizability and toolabilityAll Netscape web browsers have a built-in ORB supportEasy to support legacy codeSignificant progress in service standardizationUltimate goal is distributed system integration

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Major Component Technologies …

Enterprise JavaBean (EJB)Non-visual Java components running on serversSupports most properties of our ref. ModelOnly supports Java component integrationCORBA has become implementation technique of EJB RMI. EJB provides Java with friendlier user interfaceIntegration with CORBA makes EJB interoperable with components implemented in various languages on various platforms

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Major Component Technologies …

Microsoft DNABased on proprietary technology COM+ instead of open standardCOM+ = COM/DCOM + MTSBased on mature technologies for Windows applicationsClose integration with Windows applications

and IDEsMainly for Windows platform onlyLimited scalability

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ASP ChallengesScalability of ASP servers

Huge number of concurrent connections with states, unpredictable server workloadExisting solutions

– RAID disk array– Server clusters– Extensive caching– Non-preemptive scheduling

Our strategy– Formalism of scalability– Preemptive scheduling– State data management

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ASP Challenges …

Internet infrastructureReplace 32-bit IP addresses (IPv4) with 128-bit IP addresses (IPv6)With bandwidth 1012 b/s for optical fiber, communication delay is determined by router delays

– Electromechanical based mirror routing– Wormhole routing

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ASP Challenges …

MicropaymentCredit card is not practical for very small or vet large transactionsCurrent approaches under investigation include electronic money, virtual money, digital money, and smart cardsTo support distributed system integration, standards are needed to collect usage statistics, thus support microaccounting

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ASP Challenges …

SecurityCurrent solutions

– virtual private network (VPN)– Encryption– Server firewalls

Main difficulty is with careless or malicious acts of server center employeesKeep sensitive data on client site

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ASP Challenges …

Dynamic configurationMultiple clients may need different application configurationsNeither conventional client/server applications nor next-generation e-commerce application architectures currently support dynamic configuration

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ASP in Perspectives

Breaking ASP monopoliesPublic standardization of data formats of major applicationsPublic standardization of user interfaces of major applicationsOMG has provided successful examples

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ASP in Perspectives …Network-centric computing

Essence of distributed computing is to use networks to promote cooperative computing and specialized computingInternet is becoming new platform of global computing characterized by

– Component-based finer granularity– Global cooperation and specialization– Multimedia data– Binary integration– Mobil computing– Omnipresence in electrical/electronic devices

Networked economy characterized by integration of services