Multi-robots systems require dedicated tools and models for their design and the deployment. Our approach proposes service-oriented architecture that can simplify the development and deployment. In order to solve the problem of neighbors and service discovery in an ad-hoc network, the fleet robot needs a protocol that is able to constantly discover new robots in its coverage area. To this end we propose a robotic middleware, SDfR, that is able to provide service discovery. This protocol is an extension of the Simple Service Discovery Protocol (SSDP) used in Universal Plug and Play (UPnP) used in dynamic networks generated by the mobility of the robots. Even if SDfR is platform independent, we propose a ROS (ROS, 2014) integration in order to facilitate the use. We evaluate a series of overhead benchmarking across static and dynamic scenarios. We also present some use-cases where our proposal was successfully used.