The Pitfalls of Distributed Protocol Development: Unintentional Interactions between Network Operations and Applications Protocols

The internet today is not as transparent as was envisioned at its inception. While most of the responsibility for handling advanced communications functions remains concentrated in the end systems, we are deploying more sophisticated processing inside the network. Applications and application-level protocols such as end-to-end security and congestion control can interact in unexpected ways with network based functions such as proxies, address translators, packet filters, and nodes that perform traffic shaping and differentiated services functions. In this paper we review several recent examples of these types of interactions and extract from these examples a sense of the basic protocol functions that cause potentially harmful interactions. Currently the mitigation of these interactions has to be addressed on a case by case basis in each development effort. We suggest possible formal remedies that, if accepted as part of the protocol development process, can improve the probability that protocol interactions are handled correctly. We also propose the creation of a diagnostic capability that can assist an application user or administrator in locating the cause of an applications failure without exposing the network to denial of service attacks inherent in the use of automatically generated network management response messages