The Service Domain and service operation specifications define the main features and characteristics that are likely to apply in the significant majority of deployments. BIAN recognizes that when the BIAN standards are applied there will be variations and specializations required to align to legacy systems and to reflect differences due to factors such as geopolitical differences, the scale/type of enterprise, and the level of sophistication to the required solutions. As the content of the standard is expanded BIAN will define standard categories for these variations and implement mechanisms that can be used to select and filter as necessary.