Towards a Common Interface for Underwater Acoustic Modems

Commercially available underwater acoustic (UWA) modems are configured and operated through manufacturer-specific interfaces. This hinders the underwater communications community, because users must learn an entirely new interface for each type of modem. In this paper, we propose the first steps towards a Common Control Interface (CCI) for UWA modems. In terms of a popular networking conceptual model, the CCI consists of a data plane and a control plane. For both the data plane and control plane, the UWA CCI specifies the physical and data link layers be based on the Ethernet protocol. The higher layers of the control plane are responsible for configuration of the modem, and are specified through the definition of a management application programming interface (API) consisting of a Javascript Object Notation (JSON) over Hypertext Transfer Protocol (HTTP). The higher layers of the data plane are responsible for translating from the wired-side networking domain to the UWA networking domain, and are left for future discussion. Having vendors implement a common interface would allow users to reuse applications across modems. Designing the interface on widely used standards with mature tools would simplify the development process of new applications targeting acoustic modems. To demonstrate the interface, we developed software to abstract away the current serial interface of an acoustic modem and instead present the UWA CCI to the user. The prototype is tested on an inexpensive single board computer (SBC) and is tailored to a Woods Hole Oceanographic Institution (WHOI) Micro-Modem, but can be extended to support more modems.