12.2 Relationship to Previous Versions of CORBA

   The ORB Interoperability Architecture builds on Common Object Request Broker Architecture by adding the notion of ORB Services and their domains. (ORB Services are described in Section .2, “ORBs and ORB Services,? on page 13-3). The architecture defines the problem of ORB interoperability in terms of bridging between those domains, and defines several ways in which those bridges can be constructed. The bridges can be internal (in-line) and external (request-level) to ORBs.

   APIs included in the interoperability specifications include compatible extensions to previous versions of CORBA to support request-level bridging:

• A Dynamic Skeleton Interface (DSI) is the basic support needed for building request-level bridges. It is the server-side analogue of the Dynamic Invocation Interface and in the same way it has general applicability beyond bridging. For information about the Dynamic Skeleton Interface, refer to the Dynamic Skeleton Interface chapter.

• APIs for managing object references have been defined, building on the support identified for the Relationship Service. The APIs are defined in Object Reference Operations in the ORB Interface chapter of this book. The Relationship Service is described in the Relationship Service specification; refer to the CosObjectIdentity Module section of that specification.