Quality of service differentiation for smart grid neighbor area networks through multiple RPL instances

The Smart Grid (SG) optimizes the existing power grid with a reliable and secure SG Communications Network. For uplink data traffic, the Neighbor Area Network (NAN) segment's size and converge-cast traffic can be addressed with the Routing Protocol for Low Power and Lossy Networks (RPL). Additionally, a broad range of SG applications, such as monitoring, control and automation applications, have been proposed in order to achieve the anticipated SG goals. These applications, each possessing different Quality of Service (QoS) requirements such as bandwidth, latency, reliability and security, will require traffic prioritization and differentiation. Generally, QoS is addressed through queue scheduling mechanisms or prioritized channel access at the Medium Access Control (MAC) layer. In this paper, extensions to the standard MAC level QoS techniques are explored with an emphasis on network layer QoS mechanisms. Specifically, the effectiveness of multiple instances of the RPL network graph, built upon differing objective functions, for QoS differentiation is investigated. To that effect, three variants of RPL, standard RPL, multi-instance RPL (RPL-M) and multi-instance RPL with prioritized channel backoffs (RPL-M+) along with two distinct traffic classes have been examined as data traffic rate and composition was varied.