LTE-Wi-Fi radio level interworking is realized by employing traffic steering from IP layer or PDCP layer of LTE eNodeB protocol stack to Wi-Fi protocol stack. The challenges associated with radio level interworking architectures such as reliability, fine granularity in traffic steering, and minimizing out-of-order packet delivery for maximizing link aggregation benefits are not well addressed by IP and PDCP layer interworking architectures. LTE-Wi-Fi radio level interworking at RLC layer (LWIR) is a promising integration architecture which not only addresses the above mentioned problems but also improves the interworking benefits significantly. We have designed and implemented an LWIR prototype system using OpenAirInterface (OAI) as LTE network and Cisco Access Point/Atheros device with Hostapd as Wi-Fi network. In this work, we demonstrate the aggregation benefits of using LWIR architecture by employing byte level traffic steering across LTE and Wi-Fi links. © 2019 IEEE.