While an in-depth understanding of the inner workings of BIS is not necessary for the successful implementation and use of web services, it is useful to understand the steps the request and response messages go through during the processing of a single web service request. More information about particulars can be found in the reference manual for Xcentrisity Business Information Server.
A BIS server is composed of two cooperating processes: a request handler running under the control of an HTTP server (IIS or Apache), and a service program, programmed in COBOL, running under the control of the Xcentrisity service engine, which is very similar to the AcuCOBOL-GT runtime. A third process is also involved: the web client agent.