Patterns: Broker Interactions for Intra- and Inter-enterprise

74 Broker Interactions for Intra- and Inter-enterprise

4.2.4 Putting the pattern to use

This pattern can be observed in solutions such as:

򐂰 A retailer/wholesaler enabling external resellers to place orders to their

inventory management system.

򐂰 Extended value chain functions within e-Marketplaces that support

cross-enterprise processes such as demand planning and collaborative

design.

4.2.5 What's next

If you have determined that the Extended Enterprise business pattern can

provide an appropriate solution design for the application you are developing,

next select an Application pattern.

If the Extended Enterprise business pattern is not appropriate for your

development efforts, review the Business patterns to determine which pattern

best addresses your e-business needs.

4.3 Application patterns

The Extended Enterprise application patterns are presented here in order of

increasing flexibility and sophistication. As the Application patterns build on each

other, their capabilities and reliance on middleware increase, and they require

less application development effort. From the following Application patterns,

select the one that best fits your requirements:

򐂰 Exposed Direct Connection application pattern: Message/Call Connection

variations

򐂰 Exposed Broker application pattern: Router variation

򐂰 Exposed Serial Process application pattern: Also known as Managed

Public Processes

The diagram conventions shown in Figure 4-2 on page 75 are used to describe

these successful approaches in the following Application patterns.

Note: The Exposed Parallel Process application pattern is a further possibility,

but it is not currently being observed in the Extended Enterprise domain. It is

expected to appear at some later stage.

Chapter 4. Extended Enterprise pattern 75

Figure 4-2 Application pattern diagram conventions

Business and IT drivers

Table 4-3 and Table 4-4 summarize the business and IT drivers for the Extended

Enterprise application patterns and their variations.

Table 4-3 Business drivers

Business drivers

Exposed Direct Connection

Message variation

Exposed Direct Connection

Call variation

Exposed Broker

Router variation

Exposed Broker

Exposed Serial Process

Improve the organizational efficiency üüüüü

Reduce the latency of business events üüüüü

Support a structured exchange with

business partners

üüüüü

Support real-time one-way message

flows to partner processes

ü üüü

Transient data

Work in progress

Cached

committed data

Staged data

(data replication flow)

Application node

containing existing

code with no need

for modification for

this project or that

cannot be changed.

Read/write data

Read only data

Application node

containing new or

modified code

for this project.

A set of applications

whose characteristics

are unspecified. Only

the means with which

to interact with them

is specified.

A small solid circle indicates the initiating node.

A single arrow indicates that a response is not needed.

Double arrows indicate that a response is needed.

76 Broker Interactions for Intra- and Inter-enterprise

Table 4-4 IT drivers

Support real-time request/reply message

flows to partner processes

üüüü

Support dynamic routing of messages to

one of many target partners’ processes

üüü

Support dynamic distribution of

messages to multiple target partners’

processes

üü

Support shared public process flows with

partners

ü

IT Drivers

Exposed Direct Connection

Message variation

Exposed Direct Connection

Call variation

Exposed Broker

Router variation

Exposed Broker

Exposed Serial Process

Leverage existing skills üüüüü

Leverage the legacy investment üüüüü

Enable back-end application integration üüüüü

Minimize application complexity üüüüü

Minimize enterprise complexity üüü

Business drivers

Exposed Direct Connection

Message variation

Exposed Direct Connection

Call variation

Exposed Broker

Router variation

Exposed Broker

Exposed Serial Process

Chapter 4. Extended Enterprise pattern 77

QoS concerns

The following QoS concerns are of particular importance when working in the

Extended Enterprise domain.

Availability

High availability can be a particularly significant issue in the inter-enterprise

integration domain. It is important that careful availability management be used

to provide acceptable levels of customer service or, in some cases, to meet

contractual obligations regarding the availability of the application service being

provided.

Federation

To avoid overlap and inconsistencies in the implementation and management of

an inter-enterprise application integration scenario, it is crucial to clearly define

and agree to the responsibilities of each partner. In particular, agreed

mechanisms are needed for passing resource and user authentication and

authorization information between domains.

Performance

With inter-enterprise application integration, components of the end-to-end

solution are outside the enterprise boundaries and cannot be directly influenced.

As a client to an external application, it is difficult to control variables such as

response time, workload, and availability.

To minimize such dependencies, loosely coupled and reliable communications

should be considered.

Security

This topic includes a range of complex issues. To discuss each of them explicitly

is far beyond the scope of this book. For the purpose of this discussion, we

assume that the communication channel is secured by using firewalls as well as

proper authentication, authorization, and so forth.

In addition, we have to secure the exchange of the data itself. In the case of an

intra-enterprise scenario, it may be sufficient to use a trustworthy network. For

inter-enterprise communication, this is not longer valid. There is a need to protect

(encrypt) the data and be sure about the sender's identity (signature).

Important: This profile is intended as a very rough preliminary guide to QoS

concerns that differentiate this domain, suitable for high-level architectural

design. This is not a substitute for thorough analysis at a later design stage.