Tactical wireless and mobile networks are the primary networking infrastructure in the Global Information Grid (GIG) to provide end-to-end connectivity to the warfighters at the tactical edge. The highly dynamic nature of tactical edge networks raise a number of challenging issues related to data transport and service delivery in the tactical environment. To address some of these issues, DoD waveforms have increasingly leveraged layer 2 link information to make smart cross-layer multihop routing decisions. Although there has been some measure of success in providing higher end-to-end data delivery, the lack of standard interfaces between the radio and router have led to interoperability issues in environments with a heterogeneous mix of radio systems. As a result, there has been increased desire to standardize radio-to-router interfaces (R2RIs) as a means to separate radio and router functionality and to allow greater interoperability between systems. In this article, we examine three R2RI protocols currently being vetted through the Internet Engineering Task Force and currently integrated or under consideration in DoD radio systems (RFC 5578, R2CP, and DLEP), and identify their current use and applicability in the tactical edge. Furthermore, we identify some challenges in implementing any R2RI scheme into emerging systems.