The recent bloom of Internet of Things (IoT) and its prevalence in many security-sensitive environments made the security of these networks a crucial requirement. Routing in many of IoT networks has been performed using the routing protocol for low power and lossy networks (RPL), due to its energy-efficient mechanisms, secure modes availability, and its adaptivity to work in various environments; hence, RPL security has been the focus of many researchers. This paper presents a comprehensive study of RPL, its known attacks, and the mitigation methods proposed to counter these attacks. We conducted a detailed review of the RPL standard, including a recently proposed modification. Also, we investigated all recently published attacks on RPL and their mitigation methods through the literature. Based on this investigation, and to the best of our knowledge, we introduced a first-of-its-kind classification scheme for the mitigation methods that is based on the techniques used for the mitigation. Furthermore, we thoroughly discussed RPL-based intrusion detection systems (IDSs) and their classifications, highlighting the most recently proposed IDSs.

Routing Attacks and Mitigation Methods for RPL-Based Internet of Things

A–Z survey of Internet of Things: Architectures, protocols, applications, recent advances, future directions and recommendations

The emergence of the Internet of Things (IoT) and its applications has taken the attention of several researchers. In an effort to provide interoperability and IPv6 support for the IoT devices, the Internet Engineering Task Force (IETF) proposed the 6LoWPAN stack. However, the particularities and hardware limitations of networks associated with IoT devices lead to several challenges, mainly for routing protocols. On its stack proposal, IETF standardizes the RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) as the routing protocol for Low-power and Lossy Networks (LLNs). RPL is a tree-based proactive routing protocol that creates acyclic graphs among the nodes to allow data exchange. Although widely considered and used by current applications, different recent studies have shown its limitations and drawbacks. Among these, it is possible to highlight the weak support of mobility and P2P traffic, restrictions for multicast transmissions, and lousy adaption for dynamic throughput. Motivated by the presented issues, several new solutions have emerged during recent years. The approaches range from the consideration of different routing metrics to an entirely new solution inspired by other routing protocols. In this context, this work aims to present an extensive survey study about routing solutions for IoT/LLN, not limited to RPL enhancements. In the course of the paper, the routing requirements of LLNs, the initial protocols, and the most recent approaches are presented. The IoT routing enhancements are divided according to its main objectives and then studied individually to point out its most important strengths and weaknesses. Furthermore, as the main contribution, this study presents a comprehensive discussion about the considered approaches, identifying the still remaining open issues and suggesting future directions to be recognized by new proposals.

Routing Protocols for Low Power and Lossy Networks in Internet of Things Applications.

Mobile ad hoc networks provide a promising opportunity for the applications requiring instant networking in the resource constraint, multi-hop wireless environment. Routing protocols are the backbone of such networks to enable the routing under dynamic circumstances. Ad hoc on-demand distance vector routing protocol (AODV) is the predominant reactive routing protocol designed for mobile ad hoc networks (MANETs). It provides good performance in terms of hop count, packet delivery ratio, and control overhead in the network. AODV has an extensive research spectrum. Many variants of the protocol have been proposed by the researchers to achieve performance improvements and to address the variety of challenges. As there are hundreds of AODV related extensions, a systematic illustration is worth to present. In this review paper, we elaborate on the core of the protocol and discuss the evolution, its variants, extensions, and the applied concepts for improving the protocol. We have surveyed the broad domain of AODV extensions and have classified them based on the various criteria, e.g., quality, reliability, energy, security, and routing strategies, etc. This paper brings out the concept, design objective, research trends, and the current advancements in the research carried out for AODV improvement. Paper also summarizes various aspects of the research trends and portrays performance metrics, input parameters, applicable domains, and the adopted strategies for improving the protocol.

Recent advancements, review analysis, and extensions of the AODV with the illustration of the applied concept

The recent increase of connected devices has triggered countless Internet-of-Things applications to emerge. By using the Time-Slotted Channel Hopping (TSCH) mode of the IEEE 802.15.4e MAC layer, wireless multi-hop networks enable highly reliable and low-power communication, supporting mission-critical and industrial applications. TSCH uses channel hopping to avoid both external interference and multi-path fading, and a synchronization-based schedule which allows precise bandwidth allocation. Efficient schedule management is crucial when minimizing the delay of a packet to reach its destination. In networks with recurrent sensor data transmissions that repeat after a certain period, current scheduling functions are prone to high latencies by ignoring this recurrent behavior. In this article, we propose a TSCH scheduling function that tackles this minimal-latency recurrent traffic problem. Concretely, this work presents two novel contributions. First, the recurrent traffic problem is defined formally as an Integer Linear Program. Second, we propose the Recurrent Low-Latency Scheduling Function (ReSF) that reserves minimal-latency paths from source to sink and only activates these paths when recurrent traffic is expected. Extensive experimental results show that using ReSF leads to a latency improvement up to 80% compared to state-of-the-art low-latency scheduling functions, with a negligible impact on power consumption of at most 6%.

/pdf/resf-recurrent-low-latency-scheduling-in-ieee-802-15-4e-tsch-2uh9izz1bp.pdf

ReSF: Recurrent Low-Latency Scheduling in IEEE 802.15.4e TSCH networks

Route discovery for symmetric and asymmetric Point-to-Point (P2P)
traffic flows is a desirable feature in Low power and Lossy Networks
(LLNs). For that purpose, this document specifies a reactive P2P route
discovery mechanism for both hop-by-hop routing and source routing: Ad
Hoc On-demand Distance Vector Routing (AODV) based RPL protocol.
Paired Instances are used to construct directional paths, in case some
of the links between source and target node are asymmetric.

Asymmetric AODV-P2P-RPL in Low-Power and Lossy Networks (LLNs)

This draft presents an informational overview of the Wi-SUN
technology, which gives the principal characteristics of the protocols
that have been adopted. The objective is to provide overview
information for the IETF LPWAN working group. We also identify
relevant characteristics of Wi-SUN that make it suitable for
deployment in LPWWANs.

Wi-SUN FAN Overview

This document defines a 6top Scheduling Function called "Scheduling
Function One" (SF1) to reserve, label and schedule the end-to-end
resources hop-by-hop through the Resource ReserVation Protocol -
Traffic Engineering (RSVP-TE). SF1 uses the 6P signaling messages with
a global TrackID to add or delete the cells in L2-bundles of isolated
traffic flows.

Scheduling Function One (SF1): hop-by-hop Scheduling with RSVP-TE in 6tisch Networks

This document defines a 6top Scheduling Function called "Scheduling
Function One" (SF1) to schedule end-to-end dedicated L2-bundles hop-
by-hop for each instance. In addition, SF1 dynamically adapts the
number of reserved cells in scheduled end-to-end L2-bundles of an
ongoing instance through a Resource Reservation Protocol. SF1 uses the
6P signaling messages with a TrackID to add/delete cells in end- to-
end L2-bundles of each instance.

Scheduling Function One (SF1) for hop-by-hop Scheduling in 6tisch Networks

This draft presents several use cases in which WiSUN technology can be
applied, including Advanced Metering Infrastructure and Intelligent
Street Lights. The draft can stand alone as an independent draft, but
also represents a potential contribution to the "WiSUN overview"
section of [I-D.ietf-lpwan-overview].

Mingui Zhang

Papers

Asymmetric AODV-P2P-RPL in Low-Power and Lossy Networks (LLNs)

Wi-SUN FAN Overview

Scheduling Function One (SF1): hop-by-hop Scheduling with RSVP-TE in 6tisch Networks

Scheduling Function One (SF1) for hop-by-hop Scheduling in 6tisch Networks

WiSUN use cases