berkeley-helsinki summer course lecture #3: middleware architectures

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Berkeley-Helsinki Summer Course

Lecture #3: Middleware Architectures

Randy H. Katz

Computer Science Division

Electrical Engineering and Computer Science Department

University of California

Berkeley, CA 94720-1776

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Outline

• Middleware Definition and Functionality• Evolution of Enterprise Computing• Middleware Components• Commercial Middleware• Telecommunications Middleware• Summary and Conclusions

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Outline


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What is Middleware?

• Distributed software functionalities upon which applications and systems can be constructed

– E.g., Web-enabled access to databases

• Software that connects or “glues together” two otherwise separate applications, often across different computing platforms

– Transaction Processing Monitors– Distribute Computing Environments– Remote Procedure Call– Client-Server Architectures– Object Request Brokers– Services

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Middleware Functionality

• Transactions• Security• Management• Internet• Fault Management• Load Balancing

• Connectivity• Multiple Clients• Interface

Representation• Messaging• Publish/Subscribe• Java Execution

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Outline


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Evolution of Enterprise Computing

Private CorporateNetwork

Dedicated facilities/computer centers

Dedicated applications/3rd party DBMS

E.g., Oracle

Late-1980sInternal users

Limited customer/external access

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Private CorporateNetwork

Dedicated facilities/computer centers

Outsourced“Enterprise Resource

Planning” Appse.g., PeopleSoft, BAAN

1995Internal users

Limited customer/external access

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OutsourcedWeb Hosting

Dedicated FacilityOutsourcedERP Apps

1997Internal users

Internet

External Customers

Virtual Private Network

ISP Mesh

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Dedicated FacilityOutsourcedERP Apps

1997Internal users

Internet

External Customers

Virtual Private Network

ISPMesh

InternetServices

SearchCachingAdsEComm

Portal

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ApplicationsService Provider

1999

Customers

Content Delivery “Net”

3rd PartyFacilities Mgmt

Caching +Media Servers

InternetServices

SearchCacheAdsEComm


Portal

ISP Mesh

VPNs

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Outline


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Elements of Traditional Middleware

• Web applications infrastructure– Infrastructure for enabling distributed web- and Internet-related

applications

• Multi-agent systems– Infrastructure for enabling systems of cooperating independent agents

• Distributed object/component systems– Infrastructure for enabling interactions among distributed objects and

components (including three major approaches—DCOM, CORBA, and Java)

• Message-oriented middleware (MOM)– Infrastructure for message passing among distributed computing

elements

• Distributed database applications infrastructure– Infrastructure for distributed database applications

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Relevent Commercial Techologies

• Web Technologies– DHTML, XML, DOM,

HTTP-NG

• Agent Technology– Multiagent Systems

• Collaborative Apps– Notes

• Distributed App Building Blocks

– RPC & Java RMI

• Message-Oriented Middleware (MOM)

– IBM’s MQ series, Tibco’s “information bus,” Lotus Notes/Domino

• Distributed Object /Component-based Systems

– Microsoft’s COM, COM+, DCOM; OMG’s CORBA; and Java (Java Beans, Enterprise Java Beans, Javaspaces, Jini, etc.)

• Distributed DB Technologies

– XACT servers, ODBC & JDBC

Areas ofConcentration

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Architectural Framework for Enterprise Applications

Tools

HTML/ScriptingAuthoring

Rapid Applications Development

Component Creation

Team Development

UI/Navigation

Basic Dyn FormsNativehtml html

Business Process

Web Trans- Msg Script-Svr actions Queing

Integrated Storage

File Data- Mail OtherSys base Store Stores

DistributedOS

Environment

Management

Directory

Security

Networking

Base Services

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Network

Generic Enterprise Middleware Architecture

Client Enterprise Legacy

Web Server

Business Logic

XACT/DBMS

Computer Storage

UserInterface

Forms

PackagedApplications(SAP, Baan,PeopleSoft)

Old Apps &Data Sets

Network

Events

Connectors

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Distributed Systems Model

Client

Web browser

Web ServerWeb

Server

Appli-cation Server

Appli-cation Server

Appli-cationAppli-cation


DatabaseServer

DatabaseServer

1 2 3 4

• •

••

•

•

• •

•• •

•

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Client

Web

Market Segments in Tiered Systems

Database

Database

MOM

DB

DBM

OM

MOM

Web browser

Web ServerWeb

Server

Appli-cation Server

Appli-cation Server



DatabaseServer

DatabaseServer

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Market Segments in Tiered Systems

Client

CORBA

EJB

CO

M/D

CO

M

Java

COM/DCOM

CORBA

Java

CO

RB

A

EJB

EJB

EJB

EJB

JavaCORBA

COM/DCOM

COM/DCOM

CORBA

Java

COM/DCOM

CORBA

Java

EJB

Web browser

Web ServerWeb

Server

Appli-cation Server

Appli-cation Server


Appli-cation

Appli-cation

DatabaseServer

DatabaseServer

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Elements of Distributed Applications and Systems

• Collaborative Applications• Multiagent Systems• Component-Based Distributed Systems• Message-Oriented Middleware• Enterprise Application Integration• Distributed Database Application Infrastructure• Network Directories• Network Services

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Collaborative Applications: E.g., Lotus Notes

• Document-oriented, replicated, semi-structured “database”

– Asynchronous collaboration– Enhanced activity “awareness”

• Personal Information Management, Calendaring and Scheduling, People Locator, Expertise Locator, Distance Learning (“Learning Space”)

• Notes R5: improved performance, better database semantics (e.g., transaction logging)

• Built on top of “intelligent routing of mail”– High/medium/low priority of messages– Mail probes/server-to-server to determine QoS

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Multiagent Systems

• System of autonomous computations that cooperate or compete through message-oriented communications

• Individual agents attach to other objects to observe, react, control

• Intelligence, ability to adapt, learn, move usually assumed

• Decomposition of distributed apps into many, perhaps 1000's of, autonomous computations

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Component-Based Systems

• Delivers object-to-object, component-to-component, and application-to-application interoperability among distributed systems

– Objects: software constructs with state, behavior, identity, and well-defined interfaces

– Opaque units of independent production, acquisition, and deployment that interact to form a functioning system

• DCE, Java RMI, COM, DCOM, CORBA, ORB’s, object transaction servers, Enterprise Java Beans (EJB)

• E.g., BEA Systems (M3,WebLogic), Inprise (Visibroker), IBM (SOM object broker), Iona Technologies, Microsoft (DCOM), Sun (EJB)

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Alternative Object Architectures

• Java– Network-oriented programming language for mobile code– JavaBeans: Component Model for finding/composing Java applets– Java RMI: Client/server via remote method invocation– JINI: Network “Plug and Play,” Service Discovery Service

• COM/DCOM– Microsoft proprietary, not platform independent (Win/Win NT only)– Building blocks for all of the major desktop applications

• CORBA– Common Object Request Broker Architecture– Interface Definition Language (IDL) + APIs– Internet InterORB Protocol (IIOP) for client-server computing in CORBA

framework

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Message-Oriented Middleware

• Delivers interoperability between applications and middleware based on message exchange

• Includes message queuing engines (including push, multicast, event-driven processing, etc.) and application integration engines

• Uses broadcast techniques; senders need no knowledge of receivers, and the receivers need no knowledge of senders

• E.g., BEA Systems (MessageQ, Advanced Messaging System), IBM (MQ/MQ Integrator, Lotus Notes/Domino, Microsoft (Message Queue Server), Tibco (Information Bus)

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Enterprise Application Integration

• Data in Consistent Form• Distributing data to multiple legacy systems• Follow basic “business rules”• Business process automation• Update and enhance the functionality of

existing systems• Manage cross-application events and

functionality

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Event-Based Programming

Message structure• Transactional

Messages• Perishable Messages• Selection Criteria• Timers• Push or pull• Peeking or browsing• Message formats based

on XML

Events• Unsolicited

broadcasting/notification• Broadcasting• Anonymous

publish/subscribe• Sophisticated filters and

rules engines• XACT semantics are

trickier• Underlying technology is

evolving: reliable multicast, smart agents

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Event-Enabled Enterprise

• Business Events: semantically richBusiness Process: “Hire an employee”Business Goal: global control and visibility of business processes

• Access Control Lists (ACL) for security• Business Metrics: info revealed to the cockpit

– e.g., order status, orders by product, orders by customer, quote to ship, quote to bill, quote to cash time

• Stovepipe applications today• Event-oriented message and

connectivity/wrappers and connectors• Real-time analyzer/protocols and transformation

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Distributed Database-Application Infrastructure

• Delivers transaction management and inter-operability between applications and data sources

• Transaction servers (MTS and EJB), Object / Object-Relational, and Java-oriented Database Management Systems, Heterogeneous DB access

• E.g., BEA Systems (Tuxedo), IBM (DB/2, Java and JDBC), Microsoft (Transaction Server, SQL Server, OLE DB specification), Oracle (8i)

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Network Evolution

• VPNs as a business solution, not just for security

• Kinds of Services: Connectivity, Security, Scalability, Reliability

• Personalized Service Vision enabled by directory services

• Network DNA: Distributed Network Architecture

– Directory-enabled network– Policy-driven networking– Application-aware networking

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Outline


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Novell “Full Service Directories”

RealityLocationDynamic NamingAvailability

CommunityMembershipRelationshipsRoles

IdentityContact InfoCredentialsPreferences

• Distributed Name Services

• Centralized Indexed Search

• Loose Consistency Replication

• Fine-grained Discretionary Access Control

• Extensible Schema

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BEA End-to-End Architecture

BEA

OTM

Apps

EJB

Corba

BEA

TP

Monitor

Apps

Apps

AppsWebServer

BEAWeblogicAppServer

EJBApps

Servlets

HTMLPages

Databases

LegacySystems

IIOP

BEA Jolt

JDBC

JavaDesktop

MicrosoftDesktop(COM)

WebHTML

Enterprise JAVA APIs

Business Logic:Process, Workflow, Rules

Client Diversity JAVA App Server Network Resources

Management & Security

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Vitria’s Middleware Architecture

• Process Feedback• Process Analysis• Process Monitoring• Process Automation• Rules Processing• Data Transport

– Reliable Messaging– Event Messaging– Publish/subscribe

• Data Transform– Enterprise Integration

• Data Extract

• Analyzer• Automater• Communicator

– Channels– Names/QoS (reliable,

guaranteed, XACT, prioritized)

– Secure Channels (ACL on channels)

• Example Connectors– SAP R/3– Oracle– Custom

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Messaging(ObjectBus, ETX,

Rendezvous)

Connectivity(Connectors,

Message Broker)

Integration(Adapters, Content

Broker)

TIBCO Middleware Architecture

Presentation(Event Console)

SystemMonitoring

&Management

(Hawk)

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Java 2 Enterprise Edition

Tools Application Programming Model

Transactions

Messaging MailContainers

Con

nect

orsEJBs JSPs Servlets

Apple

tsJa

vaB

eans

Java 2 SDK, Standard Edition

CORBA RMI Database Naming/Directory

• Distributed Applications built from Beans• JSP: Java Server Pages (mixed HTML and Java code)

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Windows “DNA” Vision(Digital Nervous System)

Storage+

FSSQL

ServerXchg

COM+

MTS IIS MSMQWindowsServer

Storage+

FSSQL

ServerXchg

COM+

MTS IIS MSMQ

WindowsClient

Common:TransactionsSchedulingQueuing

Tra

nsp

are

ncy

Methods &Events

Replication

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Oracle 8i Architecture• Message brokering• Enterprise application integration• Security

– LDAP secure directory– SSL encryption– Application specific security policies– Roles in security

• Java in the DB• Queuing in the DB• Message broker with

transformation• Business process coordination:

new term for workflow• Business process modeling

• Reliable Queue w/ pub/sub• Rules-based• Message-broker: scalable

transformation engines• Async messaging critical for

application integration • Typed/structured messages• AQ: persistent queue in the DB,

available for business analyses• UML graphical editor for

workflow specification• Message types defined by

industries• Security

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Tivoli Enterprise Console

Event I ntegration Collects inf ormation you need and displays itall in one place

Whole picture f rom asingle console.

Cross-domain eventcorrelation

Helps you determine the actual cause ofproblems.

Concentrate on realproblems

Event Automation Automates corrective or preventativeactions

Automatically handletedious chores

GUI Rule Builder Create correlation/ automation rules with aneasy-to-use i/ f .

Develop business ruleswithout special skills

Notifi cation andEscalation

Expands visibility of problems; timeexpiration to promote severity ofsignifi cant events.

Sends e-mail, pop-ups,pages to right people.

Customizable eventgroups

Group events according to polices andpriorities

Manage resources inbusiness relevant way

Role-based delegation ofresponsibility

Delegate to operators based on role orexpertise.

Staff concentrates onrealm of responsibility

Centralized policy-basedconfi guration of adapters

Centrally define how adapters fi lter/ sendevents

Easy/ effi cient/ consistent confi guration

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Outline


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New Developments in Telecommunications

Middleware• User rather than enterprise-centric• Managing preferences, providing billing

infrastructure for services• Importance of device- and network-

independence, location-awareness• Examples:

– Microsoft Hailstorm– Sun ONE

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Microsoft Hailstorm

• “User-centric” Architecture, focused on support for the individual as opposed to the Enterprise or specific terminals or networks

– User control of information and data– Protection mechanisms for personal information: user-

consent necessary for personal information access, based on Passport authentication scheme

– Ease-of-use, personalization mechanism– Device/network-independent

• Multiple-Application and Service Cooperation– E.g., calendar, location, profile information

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Hailstorm Tenets

• User in control• Open access• Open process extensibility• Fair information practices:

– Notice: consumer notice of how information will be used

– Choice: regarding collection and distribution of personal information

– Access: to all information held about you– Security: protections built-in so no one else can

access your information without your consent

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Hailstorm Access Control

• Determine who or which services have access rights to their data

• Share data at will with any party;HailStorm will employ a strict opt-in platform for user’s data

• Revoke sharing/access privileges at will, providing a unique level of control not commonly available today on the Web

• Arrange for sharing that expires at a given time: system-managed, time-based data access revocation.

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Hailstorm Architecture• Defines identity, security, data models common to all

HailStorm services:– myAddress - electronic and geographic address for an identity– myProfile - name, nickname, special dates, picture– myContacts – electronic relationships/address book– myLocation – electronic/geographical location & rendezvous– myNotifications – notification subscription, management, & routing– myInbox - inbox items, e.g., e-mail/voice mail, including existing mail

systems– myCalendar – time and task management– myDocuments – raw document storage– myApplicationSettings - application settings– myFavoriteWebSites – favorite URLs and other Web identifiers– myWallet - receipts, payment instruments, coupons & other xact

records– myDevices – device settings, capabilities– myServices –services provided for an identity– myUsage – usage report for above services

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Sun ONE Architecture

• Open Network Environment (ONE) Motivation:

– Migrate from large, monolithic app systems/desktop-oriented client/server apps, to apps using a service-oriented application design

– App software broken down to constituent parts: smaller, more modular application components or services

– Exploit infrastructure software decomposed into discrete system services

– Modular service approach for great flexibility in system design

– Create new services by reassembling a few services into a new configuration

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What is a Service?

• App service: user or business activity, e.g., reading e-mail, getting a stock quote, authorizing a credit purchase, and procuring materials

• Sys service: system infrastructure & management functionality, e.g., storage, security, transactions, messaging, fault recovery

• Service exhibits following characteristics:– Provides interface that can be called from another

program – Is registered, can be located through service registry

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What is a Web Service?

• Web service exhibits following characteristics:

– Accessible over the Web– Exposes an XML interface– Is registered and can be located through a Web service

registry – Communicate using XML messages over standard Web

protocols – Web services support loosely-coupled connections

between systems

• Shared context: prerequisite to vision of transparent, dynamic interaction of widely distributed, heterogeneous Web services

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What is a Smart Web Service?

• Web service that understands situational context and shares context with other services

• Dynamic results based on who, what, when, where, why, e.g.,

– Service consumer's identity, individual, business, another Web service

– Consumer role at the time it invokes the service – Preferences consumer may have defined for this type of service – Security policies associated with the consumer of this service – Privacy policies associated with the consumer – Business policies associated with the consumer of this service – Physical location of the consumer – Type of client device being used to invoke the service – Past history associated with the consumer of this service or related

services – Service level agreements that exist between the consumer and

service provider

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Sun ONE Architecture

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Web Services Architecture

• Service Creation and Assembly: developer tools, assembly tools, policy tools, management tools

• Web Services: business services, service components• Service Integration: access to resources and other

services• Process Management: workflow, event processing• Service Container: run-time environment,

persistence, state management• Service Interface: connection, location, discovery,

communications• Service Platform: access to databases, directories,

messaging services, virtual machines, operating systems, hardware, storage

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Smart Web Services

• Smart policy coordinates activities according to policies associated with identity, context, roles

• Smart delivery aggregates, customizes, and personalizes service results based on context

• Smart process uses context to affect business service workflow

• Smart management ensures privacy, security, access rights based on specific situational context

– Service properly registered/locatable thru service registries – Appropriate pay-per-use or subscription agreements in place

and properly executed – Coordinate service provisioning and performs according to a

minimum QoS as determined by SLAs or other criteria – Obtain mgmt and runtime policies from smart policy facilities

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Standards Backplane

• Smart Delivery supports multiple clients using device-specific formats: HTML, XHTML, WML, VoiceXML.

• Service Container provides run-time environment for Web services; type depends on service host platform

• Smart Management: agents for devices; companies compete w/modular Web services for specific aspects

• Smart Process enable context-sensitive choreography; Change outcome of macro service by dynamically altering sequences of micro service invocations based on request context, e.g., geography, jurisdiction, maturity of the business relationship

• Smart Policy engine dynamically adapts processing, results according to rules considering user identity, auth levels, etc.

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Outline


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Summary and Conclusions

• Emergence of significant commercial middleware architectures: CORBA, now eclipsed by COM/DCOM (Microsoft), Java (Sun)

• New enterprise computing models based on Web presentation and Internet-based connectivity

• Focus of much of commercial middleware: integration of processing from Web to back-end database through event processing/format and protocol mediation

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Summary and Conclusions

• Newest proposals focus on user preference management, multi-access network and device access

• “Intelligent Services” and agent-based processing

• Whose proposals and technology will dominate?

– Computer industry proposals– Telecomm equipment industry proposals