The IoT requires software architectures that are able to deal with a large amounts of information, queries, and computation, making use of new data processing paradigms, stream processing, filtering, aggregation and data mining, all of this sustained by communication standards such as HyperText Transfer Protocol (HTTP) and Internet Protocol (IP). In contrast, due to the nature of IoT objects, very low power consumptions are required so any object can plug into the Internet while being powered by batteries or through energy-harvesting. Energy is wasted by transmission of unneeded data, protocol overhead, and non-optimized communication patterns; these need to be taken into account when plugging objects into the Internet. Existing Internet protocols such as HTTP and Transmission Control Protocol (TCP) are not optimized for very low-power communication, due to both verbose meta-data and headers, and the requirements for reliability through packet acknowledgement at higher layers, which hinders the adaptation of existing protocols to run over that type of networks. In order to interconnect as well as Internet-connect several IoT devices e.g., RFID, sensors, etc.), machines, a low power, highly reliable, and Internet-enabled communication stack is needed.
Starting in 2003, various IEEE and IETF standardization bodies started putting together a framework to the communication protocols of the emerging IoT systems. in detail, the 6LoWPAN, ROLL and CoRE IETF Working Groups have defined protocols at various layers of the Low power and Lossy Networks (LLNs) protocol stack, including an IPv6 adaptation layer, 6LoWPAN, a routing protocol, RPL and a web transfer protocol, CoAP . This protocol stack so far has been used with IEEE802.15.4 low-power radios, whose limitation in mesh-networking conditions has become apparent only recently. To overtake such limitation, the IEEE802.15.4e standard has been published in 2012 as an amendment to the IEEE802.15.4-2011 Medium Access Control (MAC) protocol. Three different operative modes have been defined in the IEEE802.15.4e standard. Among them, the Timeslotted Channel Hopping (TSCH) mode is the latest generation of ultra-lower power and reliable networking solutions for LLNs. At its core is a medium access technique which uses time synchronization to achieve ultra low-power operation and channel hopping to enable high reliability. Its core technology is similar to the one used in industrial networking technologies such as WirelessHART and ISA100.11a, resulting in comparable performance. However, unlike these industrial protocols, IEEE802.15.4e TSCH focuses on the MAC layer only. This clean layering allows for TSCH to fit under an IPv6 enabled protocol stack for LLNs and IoT applications.
A new Working Group called 6TiSCH has been recently formed within the IETF with the aim to link IEEE802.15.4e TSCH capabilities with prior IETF 6LoWPAN and ROLL standardization efforts and recommendations. In detail, it aims to (i) define an open standard-based architecture (very closed to the one adopted by the IoT6 project), re-using existing protocols when possible, and to (ii) face networking and routing issues, among many others. 6TiSCH will highlight best practices, and standardize the missing components to achieve industrial-grade performance in terms of jitter, latency, scalability, reliability and low-power operation for IPv6 over IEEE802.15.4e TSCH.