Holodeck B2B has a layered architecture. At the core of the solution is the Apache Axis2 framework which is used for basic SOAP processing. The Axis2 framework is extended by the Holodeck B2B Core layer which provides the ebMS functionality as specified in the ebMS V3 and A4 specifications. Around the Core layer is an interface layer (the API) which provides access to Holodeck B2B from external applications.
As the layers of this architecture are strictly decoupled using defined interfaces this architecture allows for easy extension and modification.