Summary requests are first verified by the VerifyReq Triveni process, whose internal structure is illustrated in Figure 9. There are various types of summary requests, and each one has an associated internal IN_PRG flag that denotes that this particular type of request is currently in progress. The CheckReq Triveni process waits for summary requests, using the JavaTriveni Await construct. If some other request is in progress, i.e., the corresponding IN_PRG flag has been set by StartProcess, then the requesting party is asked to ``retry later.'' Otherwise, the request is started, i.e., the START event is emitted by CheckReq and the appropriate IN_PRG flag is set by StartProcess.
