This paper provides an overview of the Internet of Things (IoT) with emphasis on enabling technologies, protocols, and application issues. The IoT is enabled by the latest developments in RFID, smart sensors, communication technologies, and Internet protocols. The basic premise is to have smart sensors collaborate directly without human involvement to deliver a new class of applications. The current revolution in Internet, mobile, and machine-to-machine (M2M) technologies can be seen as the first phase of the IoT. In the coming years, the IoT is expected to bridge diverse technologies to enable new applications by connecting physical objects together in support of intelligent decision making. This paper starts by providing a horizontal overview of the IoT. Then, we give an overview of some technical details that pertain to the IoT enabling technologies, protocols, and applications. Compared to other survey papers in the field, our objective is to provide a more thorough summary of the most relevant protocols and application issues to enable researchers and application developers to get up to speed quickly on how the different protocols fit together to deliver desired functionalities without having to go through RFCs and the standards specifications. We also provide an overview of some of the key IoT challenges presented in the recent literature and provide a summary of related research work. Moreover, we explore the relation between the IoT and other emerging technologies including big data analytics and cloud and fog computing. We also present the need for better horizontal integration among IoT services. Finally, we present detailed service use-cases to illustrate how the different protocols presented in the paper fit together to deliver desired IoT services.

Internet of Things: A Survey on Enabling Technologies, Protocols, and Applications

Networked sensors-those that coordinate amongst themselves to achieve a larger sensing task-will revolutionize information gathering and processing both in urban environments and in inhospitable terrain. The sheer numbers of these sensors and the expected dynamics in these environments present unique challenges in the design of unattended autonomous sensor networks. These challenges lead us to hypothesize that sensor network coordination applications may need to be structured differently from traditional network applications. In particular, we believe that localized algorithms (in which simple local node behavior achieves a desired global objective) may be necessary for sensor network coordination. In this paper, we describe localized algorithms, and then discuss directed diffusion, a simple communication model for describing localized algorithms.

https://www.cs.jhu.edu/~cs647/class-papers/Sensor%20Nets/estrin.pdf

Next century challenges: scalable coordination in sensor networks

Underwater sensor nodes will find applications in oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation and tactical surveillance applications. Moreover, unmanned or autonomous underwater vehicles (UUVs, AUVs), equipped with sensors, will enable the exploration of natural undersea resources and gathering of scientific data in collaborative monitoring missions. Underwater acoustic networking is the enabling technology for these applications. Underwater networks consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area. In this paper, several fundamental key aspects of underwater acoustic communications are investigated. Different architectures for two-dimensional and three-dimensional underwater sensor networks are discussed, and the characteristics of the underwater channel are detailed. The main challenges for the development of efficient networking solutions posed by the underwater environment are detailed and a cross-layer approach to the integration of all communication functionalities is suggested. Furthermore, open research issues are discussed and possible solution approaches are outlined. � 2005 Published by Elsevier B.V.

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Underwater acoustic sensor networks: research challenges

National Institute of Standards and Technology における超伝導研究及び生活

Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. Military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties. One main challenge in the design of these networks is their vulnerability to security attacks. In this article, we study the threats on ad hoc network faces and the security goals to be achieved. We identify the new challenges and opportunities posed by this new networking environment and explore new approaches to secure its communication. In particular, we take advantage of the inherent redundancy in ad hoc networks-multiple routes between nodes-to defend routing against denial-of-service attacks. We also use replication and new cryptographic schemes, such as threshold cryptography, to build a highly secure and highly available key management service, which terms the core of our security framework.

/pdf/securing-ad-hoc-networks-3hudjv4io2.pdf

Securing ad hoc networks

Data delivery across a multi-hop low-power and lossy networks (LLNs) is a challenging task: devices participating in such a network have strictly limited computational power and storage, and the communication channels are of low capacity, time-varying and with high loss rates. Consequently, routing protocols finding paths through such a network must be frugal in their control traffic and state requirements, as well as in algorithmic complexity - and even once paths have been found, these may be usable only intermittently, or for a very short time due to changes on the channel. Routing protocols exist for such networks, balancing reactivity to topology and channel variation with frugality in resource requirements. Complementary component to routing protocols for such LLNs exist, intended not to manage global topology, but to react rapidly to local data delivery failures and (attempt to) successfully deliver data while giving a routing protocol time to recover globally from such a failure. Specifically, this paper studies the “Depth-First Forwarding (DFF) in Unreliable Networks” protocol, standardised within the IETF in June 2013. Moreover, this paper proposes optimisations to that protocol, denoted DFF++, for improved performance and reactivity whilst remaining fully interoperable with DFF as standardised, and incurring neither additional data sets nor protocol signals to be generated.

/pdf/depth-first-forwarding-for-low-power-and-lossy-networks-1deiwqngwm.pdf

Depth first forwarding for low power and lossy networks: Application and extension

This paper explores the cooperation between the new standards for "Low Power and Lossy Networks'' (LLNs): IETF RFC 6971, denoted "Depth-First Forwarding in Unreliable Networks'' (DFF) and the ITU-T standardised routing protocol "LOADng''. DFF is a data-forwarding mechanism for increasing reliability of data delivery in networks with dynamic topology and lossy links, using a mechanism similar to a "depth-first search'' for the destination of a packet. LOADng is a reactive on-demand routing protocol used in LLNs. The purpose of this study is to evaluate the benefit of using DFF conjointly with a routing protocol. To this end, the paper compares the performance of LOADng and LOADng+DFF using Ns2 simulations, showing a 20% end-to-end data delivery ratio increase at expense of expected longer path lengths.

/pdf/a-depth-first-forwarding-dff-extension-for-the-loadng-4dajywe1fm.pdf

A Depth First Forwarding (DFF) Extension for the LOADng Routing Protocol

The optimized link-state routing protocol (OLSR) is a proactive link-state routing protocol While similar to the well-known Internet routing protocol OSPF, OLSR is designed to be simple, and to maintain connectivity in face of highly dense and dynamic networks, while being resource-economic (battery, bandwidth etc) These characteristics make OLSR suitable as an underlaying routing protocol in a wide range of ad-hoc sensor networks In this paper, we introduce an extension to OLSR: OSPF-style database exchange and reliable synchronization The goal of this extension is to provide a mechanism, through which nodes in an ad-hoc sensor network can detect and correct discrepancies in their link-state databases We qualify why the mechanism, found in OSPF, is not directly applicable for ad-hoc sensor networks, describe an adopted mechanism, accomplishing the same goal, and evaluate the performance of this mechanism in comparison to the database exchange mechanism found in OSPF We finally discuss some applications of database exchange and reliable synchronization in ad-hoc sensor networks

OSPF-style database exchange and reliable synchronization in the optimized link-state routing protocol

Many protocols for Mobile Ad-hoc Networks such as AODV propose construction routes reactively using flooding. The advantage hereof is, that no prior assumptions of the network topology are required in order to provide routing between any pair of nodes in the network. In mobile networks, where the topology is subject to frequent changes, this is a particularly attractive property. In this paper, we investigate the effect of using flooding for acquiring routes. We show, that flooding may lead to non-optimal routes in terms of number of hops. This implies that more retransmissions are needed to send a packet along a route. We proceed by providing a qualitative analysis of the route lengths. Finally, we propose and evaluate through simulations, alternative flooding schemes such as MPR flooding and Suoerflooding. MPR flooding considerably reduces the flooding overhead and provides shorter routes very close to optimal. Superfloo- ding provides optimal routes but to the cost of an significant but anyhow reasonable increase of flooding overhead.

https://hal.inria.fr/inria-00072079/document

Optimizing Route Discovery in Reactive Protocols for Ad Hoc Networks

As stated explicitly in the paper by Refsgaard et al. (‘Systeme Hydrologique Europeen (SHE): review and perspectives after 30 years development in distributed physically-based modelling’, published in Hydrology Research 41 (5), 355–377), our paper was ‘confined to a historical analysis based on our own experience through our work at DHI and, to a minor extent, the initiatives and work by DHI's ASHE partners’. We therefore welcome the comments by Ewen et al. (in this issue's Comment paper, pp. 945–947) hereafter referred to as EOBBKPO, with the views of another ASHE partner. This provides us with the opportunity to state our views even more clearly.

Thomas Clausen

Papers

Depth first forwarding for low power and lossy networks: Application and extension

A Depth First Forwarding (DFF) Extension for the LOADng Routing Protocol

OSPF-style database exchange and reliable synchronization in the optimized link-state routing protocol

Optimizing Route Discovery in Reactive Protocols for Ad Hoc Networks

Physically-based modelling, good modelling practice including uncertainty – reply to comment by Ewen et al. (2012)