SDL: meeting the IoT challenge

SDL 2010 offers excellent support for modelling, simulating and testing systems of communicating agents. However, it is not perfectly adapted to meeting the specific challenges presented by the Internet of Things (IoT). Three areas that pose a challenge are considered, and language adaptations that aim to address the specific needs of IoT systems developers are explored. The first challenge concerns signal delay or signal loss on crowded networks. Signals in SDL 2010 are by default delayed by an indeterminate duration, but a facility to model delays that depend on network traffic would be desirable. A modification is proposed to enable this. The second concerns undesirable interactions with external IoT systems. SDL 2010 supports modelling of a system within an environment populated by multiple agents. It also allows modelling of multiple interacting subsystems. However, it would be useful to be able to model interactions with external agents in a way that supported identification of threats to reliability, privacy and security of an IoT system. An adaptation of channel substructures, a construct that was dropped from SDL 96, is proposed to facilitate this. The third and final challenge concerns the signal handling by multiple recipients. Different approaches to supporting this are considered with a view to further investigation to determine their desirability