This work describes the integration of the hard real-time IP/UDP stack rtludp-0.1.1 into the Real- time Ethernet Device Driver (REDD)[1] of the free real-time Linux distribution RTLinux. The current implementation of REDD misses a high-level communication protocol as it is present for non real-time TCP/IP. A high-level communication protocol is essential for high-level applications and middleware (e.g. for using REDD for a publisher/subscriber protocol[2]). This paper describes the design decisions in inte- grating rtludp-0.1.1 into REDD, analyzes the impact of the layering of the communication protocol on the bandwidth and the latency by means of benchmarks, and points out some ideas for future development.