Inter-operability and distributed application platform design

Interception is the process which creates and inserts the appropriate gateways when a binding between a client and a server is established across domain boundaries. The inserted gateways can perform the required transformations in the case of technical differences, the checking and vetting in cases where administrative boundaries are necessary, and the monitoring where auditing is required. The paper introduce a model of interception and then shows how it can be used to explain the implementation alternatives which face system and application integrators who are concerned with inter operability between different distributed platforms. The paper then looks in detail at one application of interception, namely that of passing interface references through domain boundaries. In particular the structure of interface references required to facilitate the different implementations, and the role of binding in this process are explained. The implications of implementing the different approaches on the design of distributed platforms are then discussed. This paper provides a model which explains the issues discussed in the OMG CORBA Universal Networked Object (UNO) proposal [UNO 95], as well as discussing some of the issues which are not tackled by the proposal.