Federating Traders: An ODP Adventure

In this paper we propose a model of decentralized federation of traders. Each component trader manages its own set of federated traders. A federation contract is used to document the agreement between two federating traders. The importer's portion of the federation contract forms an import contract that states the service types available in the remote trader. The exporter's portion of the federation contract forms the corresponding export contract that states the extent of allowed access of a remote trader to the local trader's database. The contracts also contain mapping functions for requests and results, to be expressed in a canonical form for communication between traders. There are two protocols: one for a user with its trader and another for a trader with another trader in the federation. A user has access only to the protocols of its local trader. We present our model using the ve viewpoints of ODP, and demonstrate the need to recursively apply the ve viewpoints to engineering mechanisms of a system. We learn that there is a need for a third-party security mechanism and a separate type management function in ODP. We also discover that transparency does not imply secrecy. Finally, our experience con rms that while separation and location can be made transparent, autonomy and incremental change cannot be made completely transparent in an Open Distributed Processing environment. Keyword Codes: C.2.0; C.2.4