Service oriented architectures (SOA) and service oriented philosophy of software are a successful methodology of the development of complex software systems. Large software vendors usually use the nine layer SOA reference model developed by OASIS group.
The model prefers the top-down development of SOA and the development form scratch in rather big bang style. The developed systems tend to be quite expensive, they require a lot of staff trainig and imly netrivial changes of organizationa structure.
This paper deals with the development of SOA in bottom-up style. The development uses specific (architectural) services applied as adapters of services, integrators of composite services, brokers, enabling effective mock-up prototypes, etc.
It is shown, that various variants of architectural services can be obtained by simple modifications of a universal service. It enables agile variants of SOA developments.
The resulting system has many features of Petri nets known from the theory of parallel systems.