Section 16.4. Lessons Learned, Benefits, and Perspectives

16.4. Lessons Learned, Benefits, and Perspectives

The SOA implemented at Credit Suisse is now firmly established within the enterprise and is considered to be a major success. The main benefits experienced can be summarized as follows:

Reuse of services. The business services are used across applications. Although the average reuse factor is only 1.6 when taking into account all services, some business services are used by up to 12 applications. The low average factor is mainly due to the fact that many services are currently used by a single application. Because services are built as soon as there is a single user, it can take some time before a second user materializes. Reuse is driven by the centralized repository containing the service interfaces and detailed documentations.

More efficient application development. Due mainly to the reuse of services, application development has been accelerated considerably. Usually, when a new application is under development, 75 to 80 percent of the required services are already available in the repository. This improves time-to-market of new solutions dramatically and also offers significant cost savings for the development process.

Increase of collaboration. Another benefit consists of the increased collaboration between the business unit developers and the programmers implementing the core business applications. It was also observed that experienced PL/1 programmers, who had become demotivated over the years, participated actively in the development process.

However, these benefits were not achieved without hard work. For one thing, there was continuous uncertainty regarding the approach taken with the integration architecture. This included, for example, complaints that CORBA was too resource-intensive, too complex, and too slow. This objection was not broad-based, however, and the consistent support from top management overcame it.

There was also a critical stage when the Information Bus threatened to fall victim to its own success. As more users accessed the applications built on top of the CSIB, performance, reliability, and availability became indispensable. Again, having management backing and sufficient budget helped to overcome problems during this critical phase.

It also transpired that the decoupling, which had been achieved for internal integration, did not necessarily suffice for external integration, which posed even more demanding requirements on the degree of decoupling.

Finally, the strict bottom-up approach applied throughout the development of the SOA will probably be complemented by top-down considerations in the future. This included more systematic decisions concerning reuse and more specific targets for service developers. One idea is to reduce the overhead for the development of services that might never be reused. Another aspect is the identification of "missing" services, even if they are not immediately needed by an application.

Credit Suisse stresses four main SOA aspects that were crucial to its success:

• Interfaces

• Processes

• Management commitment

• Solid technology

Evidence for the success of the Credit Suisse SOA-based integration architecture is based on the fact that the concepts and methodologies initially developed for the synchronous information bus could be reused one-to-one when introducing the asynchronous event bus. Furthermore, the implementation of the Bulk Integration Infrastructure is also based on the same foundation. This demonstrates that both the concepts and the methodology actually produced the desired results and that they are independent from the underlying technology.

References

[Ha03] Hagen, C. Integrationsarchitektur der Credit Suisse. Enterprise Application Integration - Flexibilisierung komplexer Unternehmensarchitekturen. GITO-Verlag, Berlin, 2003.

[FMP99] Froidevaux, W. S. Murer and M. Prater . The Mainframe as a High-Available, Highly scalable CORBA Platform. International Workshop on Reliable Middleware Systems, October 1999.

[KM99] Koch, T. and S. Murer . Service Architecture Integrates Mainframes in a CORBA Environment, 3rd IEEE conf. on Enterprise Distributed Object Computing, September 1999.