VH has not delivered a response on the srecRequest in time. This information is delivered to A-EVH in a devRepCnf. 7. The response is a localPDU from B-MEH. The A-MEH checks the localPDU to see to which operation it refers. In this case it is a srecREQ. 8. The A-MEH determines which of the two possible responses of a REQUEST- class operation the ASP is. 9. The response is a srecConfirm, that includes a globalSDU. The A-MEH col- lects all information elements and delivers them to the A-EVH in a devRepCnf. 4.5 Implementing Network Service Interfaces 10. The response is a srecRefuse. No globalSDU is included, but there might be parameters that explain the refusal. The A-MEH collects all information ele- ments and delivers them to the A-EVH in a devRepCnf. The next mapping example is the global synchronous send-operation ssend- REQUEST, see Fig. 4.24: A-EVH A-MEH gevOrd(ssendReq(globalSDU,...) createLocalPdu(ssendReq(...)) T1=timer-value sendRec(in B, T1, localSDU;out r resp) Case resp time-out devRepCnf(timeOutRepCnf(...)) Case localPDU not ssendREQ -> Case ASPtype Confirm -> devRepCnf(ssendCnf(...)) Refuse -> devRepCnf(ssendRef(...)) Fig. 4.24 An implementation of the use of ssendREQUEST The global receive operation recC_REPORT would be implemented as in Fig. 4.25. A-EVH A-MEH locRec(in B, localSDU) Case localPDU not recC_REP -> -> Case ASPtype RepCnf -> devRepCnf(recRepCnf(globalSDU)) RepRef -> devRepCnf(recRepRef(...)) Fig. 4.25 An implementation of the use of recC_REPORT The global unconfirmed synchronous sendORDER would be implemented as in Fig. 4.26. A-EVH A-MEH gevOrd(sendOrder(globalSDU,...) CreateLocalPdu(sendOrder(globalSDU,...) -locSend(in B, localSDU) Fig. 4.26 An implementation of the use of sendORDER 4 Physical Network Modelling As a final example, Fig. 4.27 shows the implementation of the global uncon- firmed sendOffer (remaining global send and receive operations, see Fig. 3.28, are left for the reader to implement). A-EVH A-MEH locRec(in B, localSDU) Case localPDU not sendOFFER -> -> devRepCnf(sendO