Packet Ordering Functions in Low-power Wireless Deterministic Networks

Industrial Internet of Things applications need strict Quality of Service guarantees, including when they use wireless networks. While existing standardization efforts, such as Deterministic Networks (IETF) and Delay Tolerant Networks (IEEE), have focused mainly on wired networks, more recent activities address wireless networks, like the Reliable and Available Wireless (RAW) Working Group of the IETF. By duplicating packets over multiple paths, it is possible to improve availability and reliability, but at the potential expense of more out-of-order packets. Existing reordering algorithms, including two recently standardized by the IETF, are not always well suited to wireless networks. We propose a new reordering algorithm and simulate a 6TiSCH wireless network to compare its performance with the existing ones. We also extend existing Network Calculus bounds on the reordering timer to obtain path-dependant values that can reduce the average latency.