Section 15.1. Project Scope


15.1. Project Scope

The scope of Winterthur's SOA introduction is mainly defined by the requirements of innovative business-driven projects and the need to reuse existing mainframe applications.

15.1.1. BUSINESS IMPACT

The first pilot project to be implemented within the SOA was wincoLink, an interactive customer service of Winterthur Leben, the life insurance branch of Winterthur. It provided corporate customers with online access to all contracts and contained direct information about, for example, vested benefits. It also supported changes of contract information, such as the inclusion of new employees in a corporate contract or a change to address data.

wincoLink was chosen as the pilot project because it not only was restricted to the passive browsing of static content but also involved user interaction. This provided Winterthur with the prestigious benefit of offering the first interactive life insurance Internet application. In addition, wincoLink promised significant cost-saving potential because it reduced Winterthur's customer support by enabling customers to access and change contract information directly, avoiding the need to go through Winterthur staff. In addition, wincoLink increased customer satisfaction because the online content available for inspection was always up-to-date.

Finally, wincoLink offered the advantage of a restricted user group, namely corporate customers, which could be enlarged step by step. It was thus possible to increase the support organization and the necessary processes incrementally, while extending the user group in a parallel manner. In fact, the wincoLink project turned out to be ideal for collecting experiences associated with the SOA without any major risks.

15.1.2. TECHNOLOGY IMPACT

The focus of Winterthur's SOA is on the integration of existing host applications. One of the major incentives for the new architectural approach was the soaring cost for maintaining monolithic applications on the mainframe computer. In addition, Winterthur wanted to add new "sales" management channels to their IT infrastructure, in particular through the Internet and Intranet in order to make their applications and solutions widely available.

In Winterthur's SOA, a service is defined as a set of operations granting access to a simplified business context or to enterprise information in the form of core business entities. Winterthur distinguishes three types of services (the terminology used for this distinction is Winterthur's):

Domain-specific business services.[1] These services belong to a defined domain, using the domain-specific model to manage enterprise information. The focus is on reusing functionality related to core business entities. These services are implemented within the domain service layer that in return provides core business functions grouped by domains such as partner, product, contract, or claims. This function is subsequently reused across several applications, protecting the enterprise data by ensuring that business rules are correctly applied.

[1] According to the terminology used in this book, these would be basic services.

Services implementing business processes.[2] These services orchestrate domain specific processes from different domains in order to provide functionalities and composite information for a single business activity. Business activities are the defined atomic steps within a business process. The focus is on providing a functional, simplified business process. Reuse, however, is not the main issue at this layer. Instead, these services are implemented within the application layer and are responsible for providing the business-process context to the domain service layer. In other words, this layer acts as a facade to combine and extend services to implement the business functionality described by use cases. This layer is accessed by the presentation layer that enables the user to interact with the system.

[2] According to the terminology used in this book, these would be intermediary services, mostly facades.

Technical services. Technical services provide functionalities related to security or system management, including configuration, user administration, printing, and code services. These are based at different technical layers and are not described further in this case study.

In addition to these services, there are also application frontends, which, according to Winterthur's terminology, belong to the presentation layer:

Presentation layer. This layer contains GUI application, which are mostly HTML based (i.e., accessible using standard web browsers).

Figure 15-1 shows the 3-tier architecture used by Winterthur (a more detailed architecture will be presented later in Section 15.3). This logical layering of the architecture, which is more or less standard for current Enterprise Systems, distinguishes between a presentation layer, an application layer, and the domain and data layers and is not to be confused with physical deployment. These layers are distributed according to non-functional requirements using one of the patterns illustrated in Figure 15-2.

Figure 15-1. Winterthur's N-tier architecture.


Figure 15-2. Example patterns for layer distribution.


The initial implementation of the SOA and e-Platform focused mainly on offering reusable domain services on the mainframe computer. Its main purpose was to allow the applications to be implemented in the application layer and to use standardized interfaces to access data and functionality on the host.

As we explain in more detail later on, CORBA was used to implement the domain services. Extensions of the e-Platform that include the necessary standards, processes, tools, and guidelines toward EJB, asynchronous messages and Web services are currently being defined.

Figure 15-3 shows the services landscape of Winterthur with six top-level domains and their respective sub-domains. Winterthur uses these domains to structure their services and define degrees of decoupling. Whereas services within a sub-domain are not necessarily completely decoupled, there are no dependencies between services from different domainsthat is, decoupling is complete across domain boundaries.

Figure 15-3. Winterthur's Non Life Applications (NLA) services landscape 2003.


One reason for this "mixed" approach is that decoupling is both costly and risky at times. It is therefore reasonable to place an initial limit on the degree of decoupling and choose a rather coarse-grained structure, as illustrated by the top-level domains in Figure 15-3. These top-level domains constitute the main application groups offered by Winterthur and provide a clear intermediate structure for which service contracts and application frontends can be designed.

According to the SOA philosophy underlying Winterthur's e-Platform, services provide given functionality as coarse-grained operations. To capture this functionality, technology-independent service contracts are established. These contracts are published in a repository and contain interface definitions and descriptions of data elements used. From the SOA's point of view, services are completely defined by these contractsthat is, a service constitutes a black box with respect to all internal aspects of the service implementation and is not visible in the contract.

This black box approach allows a rather effective decoupling of clients and servers in addition to the transparent location of service implementations.

Currently, 66 services are in production, another 21 are under development, 26 are in the test phase, and 3 additional services are planned for the near future. Every service contains one to three operations.



    Enterprise SOA. Service-Oriented Architecture Best Practices
    Enterprise SOA: Service-Oriented Architecture Best Practices
    ISBN: 0131465759
    EAN: 2147483647
    Year: 2003
    Pages: 142

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