A Survey of Coap Congestion Control in the Context of 6Tisch Networks for Real-Time Applications

CoAP (Constrained Application Protocol) is a RESTful protocol standardized by the IETF and widely used for IoT applications. 6TiSCH (IPv6 over the TSCH (time-slotted channel hopping) mode of IEEE 802.15.4e networks provide deterministic communication and high reliability through TSCH which makes them suitable for real-time IoT applications. In the context of constrained networks, network congestion can have a severe impact on the performance of real-time IoT applications. This paper reviews state-of-the-art congestion control mechanisms for CoAP in the context of 6LoWPAN (IPv6 over Lowpower Wireless Personal Area Networks) and 6TiSCH networks, emphasizing their applicability to real-time applications. In addition, it identifies key gaps in existing techniques and offers insight into optimizing network protocols for constrained environments.