Enforcement of server commitments and system global constraints in SOA-based systems

Under Service oriented architecture (SOA), a system - such as an enterprise - consists of multiple heterogeneous servers (service providers), which may be distributed over a wide area of network, and may be managed under different administrative domains. One of the goals of this work is to enable the system as a whole (i.e., the enterprise) to impose global constraints on the interactive behavior of the various heterogeneous servers. Moreover, individual servers typically make explicit or implicit commitments to their clients regarding the services they provide. Such commitments may include such things as privacy policies, and SLAs, as well as run-time promises to reserve certain merchandise for a specified time period. But the SOA methodology provides no guarantees to clients that the commitment made by a given server would actually be satisfied. Our second goal is to enforce certain types of commitments made by servers, provided that these commitments conform to the global constraints imposed by the system at large. Our technique employs LGI-based middleware to enforce stateful policies, and does not require any change of the conventional SOAP-based protocol, the UDDI server, or the programs employed by servers and their clients.