Experience with distributed objects in a portable and multithreaded library for a LAN/WAN gateway application

Design of a multithreaded, object oriented C++ class library for a simple LAN/WAN gateway application is described. The design supports both the algorithm used in various existing commercial products and another simple and enhanced algorithm. The design takes advantage of the inheritance and polymorphism properties of the object oriented paradigm, is based on Remote Procedure Calls (RPCs), and is expressed in terms of a portable, heterogeneous set of port objects. The multithreaded performance is modelled, and is compared to long duration observed values. RPC environments are becoming widespread, but their application-level performance characteristics are not well-understood. This experiment is one of the first such reported for object-oriented RPC environments. Instructive observations, based on this experience, about the library and concurrent RPC performance modelling technique are presented.