Modeling of business processes as Autonomous Agents. The unit of actions is a Service Process, which consists of a set of operations according to a defined sequence - Sequential and parallel control flow constructs - Transaction support - Custom correlation of messages - Flexible handling of exceptions - Dynamic service referral - Contracts to agglomerate services 1.1 XLANG Pros - Defined as an extension to WSDL - Availability of complicated control structures and exception handling 1.1 XLANG Cons - Does not enable exporting activities of individual services as part of the workflow - Does not explicitly handle recursive composition of Web Services - Relies on the ambiguous outgoing operations of WSDL - Does not address lifecycle for individual services 1.1 XLANG and the pi-calculus One of the most interesting features of XLANG is the support for explicit exception handling and compensating transactions. Compensating transactions are a crucial emering pattern in the scenario of Service Oriented Computing. Compensation triggering, as implemented by the Microsoft XLANG engine BizTalk, has been modelled with the pi calculus in {link:http://www.cs.unibo.it/~laneve/papers/biztalk.pdf} . 2005-08-02 14:34:47.525 2004-09-13 11:28:46.94