Patterns: Extended Enterprise SOA and Web Services

Chapter 13. Exposed Router runtime pattern: SOA profile 389

13.2 Design guidelines

In this section, we analyze the business requirements and apply Patterns for

e-business to determine the appropriate runtime pattern for the solution. We then

discuss the various design options available to us in implementing the solution

and also look at the product mappings.

13.2.1 Analyze business requirements

The business scenario requires the replenishment order request from the

Warehouse application to be forwarded to, at most, one of the multiple partner

Manufacturer applications and services. This requires moving the routing rules

from the individual applications within the enterprise to the integration

middleware component.

The benefits of moving the routing logic out to the integration middleware

component are:

򐂰 It allows the integration of multiple, diverse partner applications.

򐂰 It provides routing services, relieving the source application from being aware

of the target application.

򐂰 The use of a central router minimizes the impact of changes in location of the

target application.

The solution also needs to support the definition of trading partner profiles

delineating preferences, entitlements and contacts.

13.2.2 Selecting a pattern

We use the Patterns for e-business to determine the appropriate Runtime pattern

to apply to this scenario.

Described here is a step-by-step approach used to navigate the Patterns for

e-business asset catalog:

1. Business pattern

We select the Extended Enterprise business pattern because the given

scenario requires interactions between the business processes in the

Warehouse and Manufacturer systems that reside in separate enterprises.

2. Application pattern

Because the source application (Warehouse) initiates an interaction that is

forwarded to, at most, one of many partner (Manufacturer) applications, we

choose the Router variation of the Broker application pattern as shown in the

Figure 13-2 on page 390.

390 Patterns: Extended Enterprise SOA and Web Services

Figure 13-2 Exposed Broker application pattern:: Router variation

3. Runtime pattern

The selection of the application pattern provides us with the possible runtime

patterns for the proposed solution. Because this solution requires building an

SOA infrastructure, we select the SOA profile to customize the solution to the

SOA environment.

Figure 13-3 on page 391 shows the level 0 decomposition of the SOA profile of

the Exposed Router runtime variation, mapped on to the Exposed Router

application variation.

Partner B

Partner A

Inter-

enterprise

Zone

Enterprise

Demilitarized

Zone

Enterprise Secure Zone

Partner Zones

Source

Application

Router

Rules

Target

Application

Target

Application

Partner C

Target

Application

R/O

Router Rules

Chapter 13. Exposed Router runtime pattern: SOA profile 391

Figure 13-3 Exposed Router runtime pattern = SOA profile

13.2.3 Analyze design options

This section discusses the architectural decisions that we made and their

implementation options for the given business scenario using the Exposed

Router runtime variation.

Most of the design decisions made in the previous chapters, also apply to the

Router interactions:

򐂰 “Architectural decision: integration options” on page 163 discusses the use of

Web services to integrate with the external partner services.

򐂰 “Architectural decision: implementing an ESB” on page 244 discusses the

service integration bus component of WebSphere Application Server is used

to implement the ESB.

򐂰 “Architectural decision: Maintaining an audit trail” on page 246 discusses the

Exposed ESB Gateway component handles the auditing aspects of the

interactions with the extended enterprise.

Inter-enterprise

Zone

Enterprise

Demilitarized Zone Enterprise Secure ZonePartner Zone

App Server/

Services

App Server/

Services

Network

Infrastructure

ESBESBESB

Domain FirewallDomain Firewall

Exposed

ESB

Gateway

Protocol FirewallProtocol Firewall

Connector

App Server/

Services

App Server/

Services

<Service Consumer>

App Server/

Services

<Service Provider>

Directory

& Security

Services

Router

Rules

Source

Application

Exposed Broker: Router variation

Target

Application

Partner A

Target

Application

Partner B

Target

Application

Partner C

R/O

Router Rules

392 Patterns: Extended Enterprise SOA and Web Services

There are also additional design decisions that are specific to this scenario,

which are discussed in the following sections.

Architectural decision: implementing the Exposed ESB

Gateway

Table 13-1 summarizes the requirement for the Exposed ESB Gateway

component and looks at the various alternatives that are available.

Table 13-1 Architectural decision: implementing the Exposed ESB Gateway

Decision title The most suitable operational topology

Issue or Problem statement Product selection for implementing the Exposed

ESB Gateway component that satisfies the

following requirement:

1. Provides a controlled and secured access to

external services.

2. Partner profile management.

Assumptions None.

Motivation Keeping in mind that ITSO Good has plans to

expand and enter into agreements with some more

partner Manufacturers. The ability to support

different business protocols such as EDI,

RosettaNet, and AS1/AS2 could prove to be a

differentiating factor.

Alternatives 1. Web services gateway component of the

WebSphere Application Server Network

Deployment V6.0.

2. WebSphere Partner Gateway.

Decision The WebSphere Partner Gateway is used to

implement the Exposed ESB Gateway component.