The most wide-spread wireless technologies are 3GPP cellular networking solutions (e.g., LTE-A) and IEEE WLAN solutions (e.g., WiFi). Traditionally, these two served distinct purposes. Cellular systems were commonly used for outdoor and long-range communication with limited data-rate, whereas WiFi networks provided short-range communication within residential and office environments. The operational distinction between these two technologies has (almost) disappeared within the past few years, encouraging a more seamless multi-RAT capability in 5G networks. In this poster, we illustrate and evaluate a full-stack and real-time implementation of a multi-RAT system, whose implementation will be publicly made available.