I always like getting feedback (see my e-mail address below) and I received feedback from multiple sources after my last article, which dealt with CMDB federation.

CA called to let me know that the Aprisma product I referred to is still branded as Spectrum, which was its original name back before Cabletron spun it off in 1999 as part of Aprisma Management Technologies (which was acquired by Concord, which was acquired by CA in 2005). I stand corrected. Next, at a recent analyst event I encountered an analyst who was adamant that federation was another marketing ploy to siphon big bucks out of unsuspecting IT managers. Finally, I received an e-mail from a reader who wanted to know "what the heck federation means, anyway." I can't help the analyst, but hopefully this article will address the reader's question.

The idea behind federation, as it is emerging today, is the concept of linking multiple technologies for the purpose of scaling, providing a virtualized holistic system view, or both. It's actually a very old idea that predates technology. Think of the Confederacy in the American Civil War, which was essentially a coalition of states that banded together to become more powerful.

From the perspective of the CMDB, federation serves a similar purpose. The ITIL concept of a CMDB doesn't specify implementation details. And as time goes on and technology becomes increasingly complex, many vendors are finding that more and more information is needed to manage today's complex technology. The result is that, while ITIL focuses on CMDB Configuration Items (CI) as infrastructure elements and their relationships, today's CMDBs are also storing additional information that has become increasingly relevant over time. Since it isn't always practical to store widely diverse data such as change requests, licensing information and XML documents in a single enormous database, the idea of federation has emerged as a way to simplify information storage and access. For example, BMC's Atrium CMDB stores information relevant to the overall management suite, while BMC's Performance Assurance solution includes its own "extension" CMDB, with information relevant to capacity management.

The federation concept has also been extended to SOA registries and repositories. Registries contain a catalog of available services and their characteristics and enable service-to-service bindings. Repositories contain runtime policies and contracts and provide the basis for services to be tailored at runtime based on configurable metadata. However, many large enterprises have multiple registries, multiple repositories, and different business units might have products from different vendors. Registry/repository federation provides for both scaling and performance, as well as integration between business units. It is a key concept, especially for large enterprises.

Denise Dubie is senior editor with Network World.