Abstract—The adoption of new hardware and software architectures will make future generations of pervasive devices more flexible and extensible. Networks of computational nodes will be used to compose such systems. In these networks tasks will be delegated dynamically to different nodes (that may be either general purpose or specialized). Thus, a mechanism to verify the reliability of the nodes is required, especially when nodes are allowed to move in different networks. In this context, the reliability of nodes is determined by their ability to execute the tasks assigned to them with the promised performances. This paper proposes a protocol to evaluate the reliability of the different nodes in the network, thus providing a trusting mechanism among nodes which can also manage the soft/hard real-time constrains of task execution. Some simulation results are also shown to help describing the properties of the protocol.