| 摘要 |
<p>When implementing services compiled of service independent building blocks (SIB) in an intelligent network, the SIB parameters to be relayed in computer instructions are replaced with a global data structure, whereby no parameters at all are transferred in the instruction call. Having no parameters means that each SIB receives the parameters it needs from one global variable. The global variable is visible to all SIBs, whereby each individual SIB fetches the parameters it requires from it. As regards some SIBs it is rather certain that they will remain unchanged and thus really service independent, but for some there is no such certainty, and for this reason the SIBs may be divided logically into two groups: assisting and performing SIBs respectively. Parameters of the performing SIBs are not relayed in the sub-programme call, but in one or several global data structure variables. The global variable is some data structure which is suitable for the purpose and in the fields of which the assisting SIBs place their information and from the fields of which the performing SIBs fetch the information they need. In the placing and fetching of information reference is made to a field of the data structure with the aid of an unambiguous field identifier. In addition, use of the information is conditional so that the information will be used only if the information differs from a certain initialisation value. In this way it is ensured that the building blocks (SIB) to be used in the implementation of telecommunication services in an intelligent network are service independent.</p> |
