Abstract: A modular data network protocol conformance test system is designed to make distinct the key functionality that is required in protocol conformance testing such that the system can be reused across different platform testing, protocol testing, and network topology. As a result, in its current design, it can be used to test devices as distinct as cable modems, routers, and tag-switching routers. Consequently, the system has a packet generation module that generates send packets for transmission to the UUT (unit under test) and that analyzes the receive packets from the UUT. A separate network handling module transfers the send packets to and acquires the receive packets from the UUT.