The Service Component Architecture (SCA) is a set of specifications that describe a model for building applications and systems using a Service-Oriented Architecture (SOA). WS-BPEL processes can be used as SCA components.
The OASIS SCA/BPEL Technical Committee works to advance the SCA WS-BPEL Client and Implementation (BPEL C&I) model, which specifies how SCA component implementations for SOA can be written using BPEL.
SCA is based on the idea that business function is provided as a series of services, which are assembled together to create solutions that serve a particular business need. These composite applications can contain both new services created specifically for the application and also business function from existing systems and applications, reused as part of the composition. SCA provides a model both for the composition of services and for the creation of service components, including the reuse of existing application function within SCA compositions.