Protocols for Remote Data Management in Intelligent Networks CS1

Abstract

The goal of this paper is to give a comprehensive description of the IN CS1 protocol on the SDF-SCF interface as defined by CCITT and ETSI. It explains what has been specified, how to use the existing standards and what are their necessary evolutions for later phases. After providing an overview of data management in CS1, the CCITT CS1 SDF-SCF protocol (i.e. the User Data Manipulation INAP ASE) is presented. The stress is especially put on the shortcomings of the recommendation in regard to the requirements of services such as UPT or VPN. We first explain why a Directory solution has been preferred to other approaches. Then we give an overview of the operations (Bind, Search, ModifyEntry) to be included in the Q.12xx recommendations. The underlying information model is briefly presented. The key concepts of this model are introduced (object orientation, hierarchical structure...), with a special attention to the aspects which impact the protocol (e.g.. attribute definitions, object naming ... ). Then each operation is presented with the protocol elements used to construct its argument and result (attribute value assertions, filters, scope ... ). The description of the operation procedures serves as a means for explaining how the Information Model description impacts the behaviour of the SDF when processing one of these operations. Security issues and their impact on the protocol are also dealt with. After having described the database operations, we show the simplifications brought to the X.500 Directory Access Protocol (DAP) (e.g. aliases, ciphering, ...) and the still outstanding issues (e.g. set-to default mechanism, permitted values,...) To clarify the use of the X.500 operations and to support the findings of ITU-T in regard to this choice, a set of realistic examples is provided, based on the UPT service description. It is an opportunity to show how complex requests can be formulated using a Search operation with a combination of scope and filter mechanisms or an ModifyEntry operation with multiple actions. Finafly we discuss the evolution of the SCF-SDF interface for CS2 and upwards. We show the limitation of this kind of interface for supporting inter-network signalling procedures. We try to provide the needed improvements of the SCF-SDF interface. We also open the discussion on data distribution and on the potential use of the Directory System Protocol (DSP) for supporting the SDF-SDF interface.