INCREASING THE PORTABILITY AND REUSABILITY OF PROTOCOL CODE

Deploying protocols is an expensive and time-consuming process today, One reason is the high cost of developing, testing, and installing pro tocol implementations. To reduce this difficulty, protocols are develo ped and executed within environments called protocol subsystems, and p rotocol software is often ported instead of being coded from scratch, Unfortunately, today a variety of protocol subsystems offer a plethora of features, functionality, and drawbacks; the differences among them often reduce the portability and reusability of protocol code, and th erefore present barriers to the deployment of new protocols, In this p aper, we consider differences in subsystems and their effect on the po rtability and reusability of protocols and protocol implementations. W e then propose two different approaches, each optimized for a differen t situation, that allow protocol code implemented in one subsystem to be used without modification within other subsystems, and thus reduce the barriers to protocol deployment, We relate our experiences designi ng, implementing, and measuring the performance of each approach using , as a baseline, an AppleTalk protocol stack we have developed.