The SAE Aerospace Information Report AIR5315 - Generic Open Architecture (GOA) defines "a framework to identify interface classes for applying open systems to the design of a specific hardware/software system." JAUS Service (Interface) Definition Language defines an XML schema for the interface definition of services at the Class 4L, or Application Layer, and Class 3L, or System Services Layer, of the Generic Open Architecture stack. The specification of JAUS services shall be defined according to the JAUS Service (Interface) Definition Language document.