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Defining Enterprise Architecture

Bina Ramamurthy

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Introduction

We will describe a general framework for an enterprise architecture.Goals are not specific to a particular application but to the enterprise as a whole.Automation, streamlining, flexibility, workflow driven applications are some of the features we will focus on.

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Topics for discussion

General characteristicsBusiness system hierarchyIntegration infrastructure modelNetwork modelWorkflow modelAn enterprise integration scenarioSummary

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General Characteristics

Distributed computingComponent-based applicationsEvent-driven systemsLoose coupling of business functionsDecision support systemsWorkflow managementInternet access and personalization of interfaces

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Distributed systems

Scalability: it should be possible to accommodate increased number of user, increased number of transactions, or expand the scope of functionality.It should be possible to add servers, and sites without any major changes to the basic design of the architecture or applications.It should accommodate diverse computing platforms with proper use of interoperability standards and middelware.

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Component-based applications

Should support component-based applications.Components are sharable, replaceable building blocks.This is essential to be able to adapt quickly to the changing business needs and technology opportunities.Sun’s Enterprise Java Beans (EJB), CORBA component model (CCM) and Microsoft’s COM+.

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Event-driven process

Businesses are driven by events: an order is placed, a shipment is received, a machine fails, a person is hired.Processes must be streamlined.When a problem requiring management attention occurs in production, appropriate manager should be notified immediately. This requires a change in the design of systems and the way they interoperate. (Project 1: IncidentWeb)

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Loose coupling

Traditional: large, monolithic solutions.Desired: highly coherent focused solutions linked through the transfer of transactions in an asynchronous mode of communication.Messages queues are used for comm.Loose coupling allows for independently developed applications to interact without concern about time, internal information format, and technology.

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Decision Support Systems(p.48,49)

Enterprise integration architecture must support decision makers with these information: Current status Exceptions (system and business-based) Historical records Relevant knowledge

Currently business exceptions (what we call incidents in project1) are not recognized by systems, but rather by humans.

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Business Exceptions

Events requiring human intervention, shifts in key business indicators, violations of policies, or deviations in variables that exceed defined limits should be treated as business exceptions.Automated business processes and rules should determine immediately who should take action and with what priority.

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Project1 1. Define at least four business exceptions

(incidents).2. Define limits or exceptional conditions that

will trigger these exceptions.3. Decide who and which applications should be

“notified” about the exceptions. You may use email (mail api), messaging (message queues) or simple method invocation to implement this.

4. Define what remedial actions should be taken.5. For the cheapbooks.coms: possible

exceptions can be “out of stock”, and “denial of service”.

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Business Process Automation

Traditionally: documents were source of input and reports were produced as outputs.Current business involve interactions between humans as well as humans and computers.Business process automation: workflow management post a “work list” to a person or application. Delays can be monitored, action item can be brought to attention based on a priority.Controls can be applied to make to sure exceptions are given proper attention and actions receive proper authorization.

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Integration Infrastructure Model (fig.3.2)

LegacySystem

Adapter

Message Queue

EnterpriseCOTSApplication

DistributedComponentBased systems

Decision SupportSystem

MainControl/TransApplication

Enterprise Infrastructure

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Workflow Process Model

Business processes drive the operation of a business.Examples: (enterprise level) fill customer order, get (trivial) approval on a form.Workflow: process definition, process system, activity, requester, personal work list, resource assignment facility, process manager, process interoperability.

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Figure 3.4 Workflow Process Model

Process A instance

Process B instance

Requester

Process manager

Resource AssignmentFacilities

Personal Worklist

Process A Definition

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Component-based model

We will look at it in the context of J2EE and EJB next week.

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Enterprise Scenerio

Figure 3.8Customer, sales portal, customer representative, billing service, order processing, customer relationship manager, accounting, archives, management information, exceptions, purchasing, warehouse, supplier, carrier, shipping, carrier.. Back to customer.

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Summary

Enterprise systems: processes, applications, application components, messaging, exceptions and notification.We looked workflow model.We will look into component model later.

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Topics of Discussion

State the main ideas you’ll be talking about

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Topic One

Details about this topicSupporting information and examplesHow it relates to your audience

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Topic Two

Details about this topicSupporting information and examplesHow it relates to your audience

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Topic Three

Details about this topicSupporting information and examplesHow it relates to your audience

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Real Life

Give an example or real life anecdoteSympathize with the audience’s situation if appropriate

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What This Means

Add a strong statement that summarizes how you feel or think about this topicSummarize key points you want your audience to remember

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Next Steps

Summarize any actions required of your audienceSummarize any follow up action items required of you