Dependability is a keyword within the recent discussion about the operation of Wireless Sensor Network (WSN) as a vital part of the ever-growing Internet of Things (IoT). However, while focusing on, e.g., reliable routing it is often neglected that the energy supply is an important factor to enable dependable WSN, and thus IoT operation. Using the example of the Routing Protocol for Low power and Lossy Networks (RPL) we will show that a high operational capability is often at the expense of energy resources. Nevertheless, we will also show that this issue can be mitigated. While the resilience of RPL has been verified in a plethora of existing evaluations, the impact of simple node resets on the energy efficiency has not been investigated so far. However, resets may happen for a variety of reasons which are stated in this work as well. Thus, in the first part of this paper we examine the energy costs of resets in a RPL network. We show that such temporary node failures can have a serious impact on the network’s total energy usage depending on failure location and topology. As resets are common in real WSNs this work reveals an important weakness of RPL which can even be exploited for attacks.

To mitigate this issue, in the second part of this paper we propose a hardening of RPL by maintaining a backup of the RPL state information in a non-volatile memory. Improvements as well as limitations of this approach and a mechanism for a seamless recovery are discussed and described in detail. Finally, the effectiveness and the characteristics of the proposed approach to harden RPL are evaluated extensively.

在最近关于无线传感器网络（WSN）的运行的讨论中，可靠性是关键字，它是不断发展的物联网（IoT）的重要组成部分。但是，在关注例如可靠的路由时，经常会忽略能源供应是实现可靠的WSN以及IoT运行的重要因素。以低功耗有损网络（RPL）的路由协议为例，我们将显示出高运行能力通常是以能源为代价的。尽管如此，我们还将证明可以缓解此问题。尽管RPL的弹性已在众多现有评估中得到验证，但到目前为止，尚未研究简单节点重置对能效的影响。但是，重置也可能由于各种原因而发生，在此工作中也有陈述。从而，在本文的第一部分中，我们研究了RPL网络中重置的能源成本。我们表明，这种临时节点故障会严重影响网络的总能耗，具体取决于故障位置和拓扑。由于重置在实际的WSN中很常见，因此这项工作揭示了RPL的一个重要弱点，甚至可以利用它进行攻击。

为了缓解这个问题，在本文的第二部分中，我们建议通过在非易失性存储器中维护RPL状态信息的备份来强化RPL。详细讨论和描述了此方法的改进和局限性以及无缝恢复的机制。最后，对所提出的强化RPL方法的有效性和特点进行了广泛的评估。