Using Polymorphic Types to Structure Flexible Protocol Stacks

A new approach to structuring layered protocols using polymorphic service access points and type inheritance between protocol machines is presented Polymorphic service access points facil itate the exible instantiation of protocol machines containing the minimal functionality required by an application The type inheritance structure is induced by a vertical partitioning of the upper layers of the ISO Reference Model resulting in a non monolithic protocol stack that supports concur rent object oriented applications such as Actor systems The results presented represent a modest contribution to the research and practice of advanced protocol development The type structures in troduced demonstrate to software engineers particularly those developing layered systems software that object oriented programming techniques facilitate and enhance the implementation of layered architectures In addition the results presented provide justi cation for object oriented language designers that polymorphic and extensible type structures are useful for e ciently implementing layered communication protocol architectures