Abstract:
Low power and lossy networks (LLNs) consist of devices having limited bat1ery power, less memory, reduced processing capability. Wireless links between the devices are characterized by low data rate, high loss rate and instability. Despite several resource constraints, LLNs have emerged over the years as the first choice for remote sensing and data acquisition. RPL (Routing Protocol for low power and Lossy networks), is recently approved by Internet Engineering Task Force (IETF) as the standard routing protocol for IPv6-based LLNs. RPL uses a proactive routing approach and the sink or controller node within the network creates a Directed Acyclic Graph (DAG) of the network. RPL supports both point to point and point to multi-point communication to facilitate the data flows from nodes to sink and sink to nodes, respectively. As a result, each node has a path to the sink node and the sink has routing paths to all nodes within the network. In case of multiple sink nodes within the network, nodes attach themselves with the DAG of closet sink depending on the objective function used by RPL. In a multi-sink environment sink nodes can coordinate for evenly distributing the network load, increasing network life time, resource sharing and quick data collection. Cunently, RPL does not provide any coordination framework that can define message exchange between different sink nodes for enhancing the network performance. In this work, sink-to-sink coordination framework is proposed that utilizes the periodic route maintenance messages issued by RPL. The overall objective of this research is to enhance RPL so that in the presence of multiple static or mobile sinks within the network, the network load is distributed among sink nodes for achieving higher throughputs and longer network's life time.
