Each IN service can be thought of as a particular combination of elementary telephone functions, such as playing a message, outpulsing certain new digits, sending a certain ISUP message, and so forth. The services illustrated in this document can be thought of as "pre-packaged" combinations of these elementary functions.
But sometimes the pre-packaged services are not sufficient: some variation is desired.
Suppose the Coast Guard needs to vary their PVN routing instructions based on the phase of the moon, because when there are high tides they have to monitor certain stations more carefully. Certainly this was not forseen in the PVN service!
This is the role of the SCE. Each elementary telephone function is called a Service Independent Building Block or SIB. The SCP can implement any set of instructions based on SIBs, and the SME can handle the data base.
The Administration uses the SCE to create the new service for the Coast Guard based on the lunar calendar. This operation is a bit like modifying routing tables in an electronic switching system.
Perhaps a better analogy it that it is like using a spreadsheet with a long list of built-in functions, or like creating a data base using a sophisticated tool with a query language. In all these cases, the "programming" is done in a high-level "language" and the actual executable code (in the SCP and SMS) is not touched.
Italtel Societa' Italiana Telecomunicazioni Spa
Claudio Chiarenza, BUCT BPM
Comments to author:Claudio.Chiarenza@settimo.italtel.it
Contact for Information: Claudio Chiarenza - BUCT BPM
All contents copyright (C) 1995.Italtel S.p.a. All rights reserved. Revised: August 30, 1995