position policy for consultation gives that the administration collaboration can be performed when either one of the two rules PDP6 Rule1 and PDP6 Rule2 applies. As part of the behavior of the admin- istration collaboration, the consult administrator role, which is bound to the TelesvcDsk composite role, then triggers the evaluation of policy rule PDP5 Rule1 by sending the StartConsultation message to the consultant role, which is bound to the DoctorT composite role. The administration collaboration runs in parallel to the call collaboration as the doctor will need to look up information in the patient journal and record patient status and test Service Delivery Platforms PDP6_Rule1 T: ! (RegistrationOK consult administrator, consulter) PESM consultation C: True, consult administrator.onLine, consultant.AvailableForConsultation PDP5_Rule1 G: consult administrator. T: ? (StartConsultation, consult administrationComplete, administrator, consultant) consultant.adminUseComplete C: True, consultant. AvailableForConsultation, PDP6_Rule2 consulter.registered T: ! (RegistrationOK, G: Consultant.TalkedTo(Callee), consult administrator, External) consulter.TalkedTo(Caller) C: True, consult administrator.onLine, consultant.AvailableForConsultation G: consult administrator. administrationComplete, consultant.adminUseComplete dcp (caller -> consultant, dap (administrator -> consult administrator, callee -> consulter : call adminUser -> consultant) : administration Figure 5.9 Global PESM diagram for the consultation collaboration. results during the entire consultation by communicating with the electronic tele- consultation service desk. The call collaboration can be performed when the policy rule PDP5 Rule1 applies, that is, when the trigger has been received and the condition part of the policy rule is true. The semantics of UML diagrams are stated informally in the UML standard. As the PESM is an extension of the UML 2.x modeling language, there may be ambiguities that may lead to different interpretations of the meaning of 