1. An operational support system comprising: an application programming interface; and a plurality of software modules organized in hierarchical layers, the modules including program instructions that, when executed, invoke a module configured in an adjacent lower layer of the plurality of hierarchical layers and provide functionality to a module in an adjacent upper layer of the plurality of hierarchical layers, the modules being callable from the application programming interface, wherein the plurality of modules include a data access module, a data cleansing module and a workflow module, the data access module including program instructions that, when executed, retrieves and standardizes data from a plurality of data sources, wherein the data access module removes duplicates received from the data sources, the data cleansing module including program instructions that, when executed, provide information to identify a discord from among the plurality of data sources, the workflow module including program instructions that, when executed, automate provisioning activities of an enterprise and provide exception handling during execution of the provisioning activity, wherein the data access module, the data cleansing module and the workflow module are each callable from the application programming interface, the application programming interface identifying functions of the data access module, the data cleansing module, the workflow module and the plurality of data sources.