CoAP over ICN

The Constrained Application Protocol (CoAP) is a specialized Web transfer protocol for resource-oriented applications intended to run on constrained devices, typically part of the Internet of Things. In this paper we leverage Information-Centric Networking (ICN), deployed within the domain of a network provider that interconnects, in addition to other terminals, CoAP endpoints in order to provide enhanced CoAP services. We present various CoAP-specific communication scenarios and discuss how ICN can provide benefits to both network providers and CoAP applications, even though the latter are not aware of the existence of ICN. In particular, the use of ICN results in smaller state management complexity at CoAP endpoints, simpler implementation at CoAP endpoints, and less communication overhead in the network.Comment: Proc. of the 8th IFIP International Conference on New Technologies, Mobility and Security (NTMS), Larnaca, Cyprus, November, 201

Efficiently observing Internet of Things resources

The Constrained Application Protocol (CoAP) is a lightweight protocol that enables the implementation of RESTful embedded web services. Observe is one of the CoAP extensions, which allow servers to send every resource state change to interested clients. In this paper we present an interesting extension to the observe option, called conditional observation, where clients specify notification criteria along their observation request. We evaluate the feasibility of implementing this on a constrained device and evaluate the correct operation for a simple scenario. It is shown that the use of conditional observations can result in a reduced number of packets and power consumption compared to normal observe in combination with client-side filtering

Enhancing Block-Wise Transfer with Network Coding in CoAP

CoAP (Constrained Application Protocol) with block-wise transfer (BWT) option is a known protocol choice for large data transfer in general lossy IoT network environments. Lossy transmission environments on the other hand lead to CoAP resending multiple blocks, which creates overheads. To tackle this problem, we design a BWT with network coding (NC), with the goal to reducing the number of unnecessary retransmissions. The results show the reduction in the number of block retransmissions for different values of blocksize, implying the reduced transfer time. For the maximum blocksize of 1024 bytes and total probability loss of 0.5, CoAP with NC can resend up to 5 times less blocks.Comment: 4 pages, 2 figures, submitted to Euro-Par 201

A Low-Power CoAP for Contiki

Internet of Things devices will by and large be battery-operated, but existing application protocols have typically not been designed with power-efficiency in mind. In low-power wireless systems, power-efficiency is determined by the ability to maintain a low radio duty cycle: keeping the radio off as much as possible. We present an implementation of the IETF Constrained Application Protocol (CoAP) for the Contiki operating system that leverages the ContikiMAC low-power duty cycling mechanism to provide power efficiency. We experimentally evaluate our low-power CoAP, demonstrating that an existing application layer protocol can be made power-efficient through a generic radio duty cycling mechanism. To the best of our knowledge, our CoAP implementation is the first to provide power-efficient operation through radio duty cycling. Our results question the need for specialized low-power mechanisms at the application layer, instead providing low-power operation only at the radio duty cycling layer

Journal Staff

During the last decade, the number of devices capable of connecting to the Internet has grown enormously. The Internet of Things describes a scenario where Internet connected devices are ubiquitous and even the smallest device has a connection to the Internet. Many of these devices will be running on constrained platforms with limited power and computing resources. Implementing protocols that are both secure and resource efficient is challenging. Current protocols have generally been designed for mains powered devices; hence, they are not optimized for running on constrained devices. The Constrained Application Protocol (CoAP) is a protocol for network communication specifically designed for constrained devices. This thesis project examines CoAP and presents an extension that adds authentication in a way that is suitable for constrained devices, with respect to minimizing resource use. The proposed solution has been compared and contrasted with other alternatives for authentication, particularly those alternatives used with CoAP. It has also been implemented in code and experimentally evaluated with regards to performance versus vanilla CoAP. The main goal of this project is to implement a lightweight authentication extension for CoAP to be deployed and evaluated on constrained devices. This extension, called Short Message Authentication ChecK (SMACK), can be used on devices that require a method for secure authentication of messages while using only limited power. The main goal of the extension is to protect against battery exhaustion and denial of sleep attacks. Other benefits are that the extension adds no additional overhead when compared with the packet structure described in the latest CoAP specification. Minimizing overhead is important since some constrained networks may only support low bandwidth communication.Under det senaste århundradet har antalet enheter som kan ansluta sig till Internet ökat enormt. ”The Internet of Things” beskriver ett scenario där Internet-anslutna enheter är närvarande överallt och även den minsta enhet har en uppkoppling till Internet. Många av dessa enheter kommer att vara begränsade plattformar med restriktioner på både kraft- och beräkningsresurser. Att implementera protokoll som både är säkra och resurseffektiva är en utmaning. Tillgängliga protokoll har i regel varit designade för enheter med anslutning till det fasta kraftnätet; på grund av detta är de inte optimerade för att köras på begränsade plattformar. Constrained Application Protocol (CoAP) är ett protokoll för nätverkskommunikation speciellt framtaget för begränsade plattformar. Denna uppsats undersöker CoAP protokollet och presenterar ett tillägg som erbjuder autentisering på ett sätt som passar begränsade plattformar, med avseende på att minimera resursanvändning. Den föreslagna lösningen har blivit beskriven och jämförd med andra alternativ för autentisering, speciellt de alternativ som används med CoAP. Lösningen har också implementerats i kod och blivit experimentellt utvärderad när det gäller prestanda jämfört med standardversionen av CoAP. Det huvudsakliga målet för detta projekt är att implementera en lättviktslösning för autentisering till CoAP som ska installeras och utvärderas på begränsade plattformar. Detta tillägg, Short Message Authentication checK (SMACK), kan användas på enheter som behöver en metod för säker autentisering av meddelanden samtidigt som kraftåtgången hålls låg. Huvudmålet för detta tillägg är att skydda mot batteridräneringsattacker och attacker som hindrar en enhet från att gå i viloläge. Andra fördelar är att tillägget inte kräver någon extra dataanvändning jämfört med paketstrukturen som beskrivs i den senaste CoAP-specifikationen. Att minimera overhead i kommunikationsprotokoll är viktigt eftersom vissa begränsade nätverk endast stödjer kommunikation över låg bandbredd

6LoWPAN Stack Model Configuration for IoT Streaming Data Transmission over CoAP

Abstract: Different protocols have been developed for the Internet of things (IoT), such as the constrained application protocol (CoAP) for the application layer of the IPv6 over low-power wireless personal area networks (6LoWPAN) stack model. Data transmitted over 6LoWPAN are limited by the throughput and the frame size defined by IEEE 805.14.5 standards. Choosing the best configuration for data transmission involves a trade off between the application requirements, the constrained network configuration, the constrained device specifications and IoT application protocols. This paper provides an analysis of message size and structure recommendations for the 6LoWPAN stack model for different network topologies using CoAP. CoAP is a promising application protocol for the 6LoWPAN stack model because it can effectively manage the transmission required functionality in small header UDP packets compared to TCP packets. However, a data model is also required to realize an effective IoT model. While fragmentation and reassembly are supported by CoAP, they should be avoided for this type of model. As for any conceptual model, a high configuration between layers is mandatory. Additionally, the proposed message format is useful for semantic web of things application development and for WSN design and management

Enabling the web of things: facilitating deployment, discovery and resource access to IoT objects using embedded web services

Today, the IETF Constrained Application Protocol (CoAP) is being standardised. CoAP takes the internet of things to the next level: it enables the implementation of RESTful web services on embedded devices, thus enabling the construction of an easily accessible web of things. However, before tiny objects can make themselves available through embedded web services, several manual configuration steps are still needed to integrate a sensor network within an existing networking environment. In this paper, we describe a novel self-organisation solution to facilitate the deployment of constrained networks and enable the discovery, end-to-end connectivity and service usage of these newly deployed sensor nodes. By using embedded web service technology, the need of other protocols on these resource constrained devices is avoided. It allows automatic hierarchical discovery of CoAP servers, resulting in a browsable hierarchy of CoAP servers, which can be accessed both over CoAP and hypertext transfer protocol

Experimental evaluation of unicast and multicast CoAP group communication

The Internet of Things (IoT) is expanding rapidly to new domains in which embedded devices play a key role and gradually outnumber traditionally-connected devices. These devices are often constrained in their resources and are thus unable to run standard Internet protocols. The Constrained Application Protocol (CoAP) is a new alternative standard protocol that implements the same principals as the Hypertext Transfer Protocol (HTTP), but is tailored towards constrained devices. In many IoT application domains, devices need to be addressed in groups in addition to being addressable individually. Two main approaches are currently being proposed in the IoT community for CoAP-based group communication. The main difference between the two approaches lies in the underlying communication type: multicast versus unicast. In this article, we experimentally evaluate those two approaches using two wireless sensor testbeds and under different test conditions. We highlight the pros and cons of each of them and propose combining these approaches in a hybrid solution to better suit certain use case requirements. Additionally, we provide a solution for multicast-based group membership management using CoAP

Bluetooth Low Energy Based CoAP Communication in IoT CoAPNonIP: An Architecture Grants CoAP in Wireless Personal Area Network

In recent years, the development of smart devices has led to the Internet of Things (IoT). In IoT, the Constrained Application Protocol (CoAP) is a well-known protocol used in constrained networks. CoAP aims to work in IP-based networks. However, there are many constrained devices using different scenarios to transfer data. For example, Bluetooth Low Energy (BLE) devices use the Media Access Control (MAC) address as an identifier and use Generic Attribute Profile (GATT) to transfer data. Therefore, how to overcome those barriers is an important topic. There are several approaches to overcome those barriers. For example, a new hardware component can be added to make those devices support TCP/IP protocol stacks, then CoAP can easily be implemented in those devices. On the other hand, an application layer architecture can be added upon existing communication technologies to support CoAP. Considering to minimize the changes of underlying communication infrastructure, the second approach can achieve the goal with less effort. This thesis proposes an architecture that apply CoAP to different Non-IP based communication technologies. Meanwhile, Bluetooth Low Energy is used to explore how to overcome limitations of underlying technology. By adopting the proposed architecture, existing devices can participate in the IoT through CoAP without extra hardware upgrade or hardware modification. Although experiments show that the current implementation of the proposed architecture has relatively low data rate, the problem can be solved via ​changing the factory settings of BLE devices. Compared with the hardware solution, the proposed architecture takes less effort to support different underlying technologies and platforms

Performance Evaluation of Constrained Application Protocol over TCP

The Constrained Application Protocol (CoAP) is specifically designed for constrained IoT devices and is being rapidly deployed for the communication needs of the IoT devices. CoAP has been specified with its own congestion control algorithms because it runs on top of UDP that does not include any congestion control measures. These algorithms aim at taking into account the specific needs of the IoT communication. The need of running CoAP also over TCP has arised recently and is expected to be increasingly deployed alongside with CoAP over UDP. To understand the benefits and shortcomings of both CoAP over TCP and CoAP over UDP, we run an extensive set of experiments in different network settings and compare the performance of CoAP over TCP to the existing congestion control algorithms for CoAP over UDP. Our results reveal that even though CoAP over TCP has its known limitations it scales well and performs even better than expected in certain wireless settings that CoAP over UDP algorithms are specifically designed for, often even outperforming CoAP over UDP.Peer reviewe