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Sun Java Enterprise System Deployment Planning White Paper 

Chapter 4
Designing the Logical Architecture

This chapter discusses a process for creating a logical architecture and provides an example of the process using a set of use cases representative of those found in a communications deployment for a medium-sized enterprise.

The logical architecture identifies the Java Enterprise System components (and their dependencies) that provide the software services needed to meet the business goals of a deployment. Typically, use cases developed during the technical requirements phase indicate which software services are required. However, the information on software services can often be obtained directly from the business requirements derived during the business analysis phase.

The logical architecture, together with system requirements determined during requirements analysis, represent a deployment scenario. The deployment scenario is the basis for designing the deployment architecture. The following figure shows the relationship of the logical design phase to the business analysis, technical requirements, and deployment design phases.

Figure 4-1  Logical Design in Relation to Other Deployment Planning Phases

Diagram showing the relationship of the logical design phase to the other phases.[D]

This chapter contains the following sections:


Deployment Planning Example

To help illustrate the deployment planning process, this section introduces use cases for an example deployment based on the communications needs of a typical medium-sized enterprise. This example deployment continues in later chapters of this white paper to illustrate various steps of deployment planning.


Caution

The use cases, logical architecture, deployment architecture, and design specification for the example deployment are simplified versions of steps in a deployment planning process.

The example has been simplified for illustrative purposes. The design for the example is incomplete and has never been built or tested. Do not use the example as a blueprint for any deployment you are planning.


The example deployment begins with a set of use cases that are derived from typical business requirements for a communications deployment. The following table summarizes these use cases.

Table 4-1  Use Cases for Example Deployment  

Use Case

Description

#1
Single sign-on

From Web browser, user logs on to system (username/password) to access enterprise services, which could be any of the following:

  • Custom Portal Web page
  • Web-based e-mail page
  • Calendar interface
  • Secure Web page

#2
Open personal portal screen

From Web browser, user navigates to personal portal screen.

#3
Through portal, user checks e-mail

From portal interface, user checks for new e-mail messages.

#4
Through portal, user checks secure web page

From personal portal interface, user checks a secure project status page.

#5
Through portal, user checks calendar

From portal interface, user checks daily appointments.

#6
Manage calendar

From Web-based calendar client, user schedules appointments.

#7
Manage e-mail

From e-mail client, user reads and sends e-mail.

From these use cases, you can derive the services needed for the logical architecture, as described in following sections.


Java Enterprise System Services

Design of the logical architecture begins with an analysis of the use cases, which should help you determine the services required for the deployment. Using your knowledge of Java Enterprise System and previous design experience, lay out an initial logical design of Java Enterprise System components that provide the services identified by the use cases.

When laying out the components, consider the logical flow of data within the system and the dependencies between the components that provide the services. Your logical design should reflect these dependencies, which impact the flow of data between components in the design.

The following figure shows components provided with Java Enterprise System. Use this figure with Table 4-2 to understand the interdependencies of Java Enterprise System components. In general, components at the bottom of the figure provide support to components above them.

Figure 4-2  Java Enterprise System Components

Diagram showing the relationship among the components of Java Enterprise System.[D]

The following table lists the actual interdependencies among Java Enterprise System components.

Table 4-2  Java Enterprise System Component Interdependencies  

Java Enterprise System Component

Provides Support To

Depends On

Application Server

Identity Server
Portal Server

Message Queue

Calendar Server

Portal Server (for calendar channel)

Directory Server
Identity Server (for single sign-on)

Messaging Server (for Calendar Server e-mail notification service)

Directory Proxy Server

None

Directory Server

Directory Server

Administration Server
Calendar Server
Directory Proxy Server
Identity Server
Instant Messaging
Messaging Server
Portal Server

None

Identity Server

Portal Server

If configured for single sign-on:

Calendar Server
Instant Messaging
Messaging Server

Directory Server
Application Server or Web Server

Instant Messaging

Portal Server

Directory Server

Message Queue

Application Server

Directory Server (optional)

Messaging Server

Calendar Server

Portal Server (for messaging channel)

Directory Server
Web Server
Identity Server

Portal Server

Secure Remote Access

Directory Server
Application Server or Web Server

If configured to use Portal Server Channels:

Calendar Server
Messaging Server
Instant Messaging

Secure Remote Access

None

Portal Server

Web Server

Identity Server
Portal Server

None

For example, to lay out the Java Enterprise System components for the example communications deployment, analyze the use cases listed in Table 4-1. The following table lists the components directly required for the deployment, as indicated by the use cases.

Table 4-3  Java Enterprise System Components to Support Example Use Cases  

Java Enterprise System Component

Use Cases

Portal Server

#1 Single sign-on

#2 Open personal portal screen

#3 Through portal, user checks e-mail

#4 Through portal, user checks secure web page

#5 Through portal, user checks calendar

Calendar Server

#1 Single sign-on

#5 Through portal, user checks calendar

#6 Manage calendar

Messaging Server

#1 Single sign-on

#3 Through portal, user checks e-mail

#7 Manage e-mail

You also need to determine which Java Enterprise System components are needed to support the components listed in Table 4-3 above. The following table lists these additional components.

Table 4-4  Additional Components to Support Example Use Cases

Java Enterprise System Component

Support Provided

Identity Server

Provides support to Portal Server.

Provides single sign-on support to Calendar Server and Messaging Server.

Directory Server

Provides support to Identity Server and Portal Server.

Application Server or
Web Server

Provides support to Identity Server and Portal Server. (Identity Server and Portal Server must run inside a web container.)


Logical Architecture for the Example Deployment

Figure 4-3 below shows the layout of components for the example deployment, indicating user entry points to the deployment. The figure places the service requiring the most support (Portal Server) at the top and lists supporting components beneath it, roughly reflecting the dependencies between the components (as described in Table 4-2). The figure does not depict the component providing the web container to support Portal Server and Identity Server because this dependency does not reflect the flow of data in the deployment.

Figure 4-3  Java Enterprise System Components in a Logical Architecture

Depicts the services in the logical architecture for the example deployment, showing their relative relationship.[D]

Data Flow for the Example Deployment

Study the use cases to determine the logical flow of data between services in the logical architecture, and indicate this flow in the layout. The flow of data between the services in a system plays an important role when sizing for performance and availability, as described in Sizing a Planned Deployment.

The following figure depicts the flow of data for the example deployment. The data flow is determined from the use cases for the deployment as well as the Java Enterprise System service dependencies.

Figure 4-4  Logical Flow of Data for the Example Deployment

Depicts the flow of data between the components in the logical architecture.

Figure 4-4 calls out the data flow that satisfies both use cases 1 and 2. This data flow represents the following:

The remaining data flows in Figure 4-4 are similarly derived from the use cases and server dependencies.


Deployment Scenario

The completed logical architecture design and the system requirements derived during requirements analysis constitute the deployment scenario. The deployment scenario is the starting point for designing the deployment architecture, as explained in Chapter 5, "Designing a Deployment Architecture."



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