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Modern Building Automation Systems (BAS) consist of sensors and actuators that are connected via an IP-based network and offer their functionality via RESTful APIs. Because a single device can be exploited by an attacker to perform attacks within the local network, we put devices into isolated groups. These groups are isolated MAC-layer Trust Zones to reduce the attack surface in contrast to a BAS with fully connected devices. We propose an algorithm that leverages the so far neglected potential of Building Information Modeling (BIM) to compute Trust Zones. We assure unimpaired operation of all applications while limiting the number of infrastructure devices. The proposed mechanisms are demonstrated considering sensors and actuators that are connected via wired Ethernet and the IEEE 802.11s WLAN mesh standard. At the application layer we make exemplary use of the Constrained Application Protocol (CoAP). Finally, we experimentally evaluate the device acquisition and selection based on our network partitioning algorithm.

Most wireless sensor networks (WSN) consist of gateways and also sensor nodes that operate devices that have limited resources, and to introduce effective communication it is necessary to choose an application protocol that allows data to be transmitted more securely and with low bandwidth and energy consumption. For V2V (vehicle-to-vehicle) and V2I (vehicle-to-infrastructure) systems, certain protocols cannot guarantee solid security with low energy consumption. This paper will identify the issues of two main application layer protocols used for Vehicular and infrastructure communication, Among the most well-known protocols in the automotive industry is Message Queuing Telemetry Transport (MQTT) and Constrained Application Protocol (CoAP), such as review our solution using elliptic curve cryptography into the two protocols to fix privacy and communication problems with low energy consumption.

Cloud Computing and the Internet of Things (IoT), two different technologies, are already part of our lives. Their impressive adoption increasing more and more, which makes them the future of the future internet. The tsunami of interconnectivity between objects and data collection is increasingly based on Cloud Computing, where data analysis and intelligence really reside. A new paradigm where the Cloud and the IoT are merged will create a new air in the world of technology, which can offer many services and applications useful to humanity. However, despite the great benefits that can bring this technology in term of new services, elasticity and flexibility, the security aspect still remains a serious constraint which hampers the expansion of this technology. This paper proposes a lightweight Mutual authentication protocol based on Constrained Application Protocol (CoAP); that is suitable for IoT devices than HTTP and using elliptic curve cryptography to secure data transmission between the Cloud and devices. We used the AVISPA tool to verify our proposed scheme.

Recently the Internet of Things (IoT) have gain much attention and, therefore, the demands for various streaming applications based on the IoT have increased. In this regard, the Constrained Application Protocol (CoAP) is a lightweight transmission protocol widely used in the IoT environment for providing streaming services. Generally, the CoAP protocol defines two message types i.e. confirmable message and non-confirmable message. However, since CoAP is not originally a transmission protocol design for streaming applications. Therefore, it cannot guarantee the reliability and real-time performance when streaming media is transmitted over it. In this paper, we propose a method to improve the QoS of streaming media transmission by dynamically changing the proportion of confirmable messages and non-confirmable messages. As the network conditions gradually gets better, the proposed method appropriately reduces the proportion of confirmable messages to meet the real-time requirements of streaming media. Finally, the simulation results show that the proposed scheme significantly enhances the QoS of the CoAP protocol for streaming service.

Internet of Things (IoT) can be defined as the interconnection through Internet of an unprecedented number of devices with the purpose of exchanging data. It stands as one of the most popular technologies for the following years and it is requiring substantial changes in the Internet protocols to meet its requirements. As the application layer is decisive for the quality of the connection, this paper analyzes the performance offered by one of the most popular protocols for the application layer in IoT: the Constrained Application Protocol (CoAP). This analysis aims to examine the features and capabilities of this protocol and to determine its feasibility to operate under constrained devices using security support. For this, a realistic network scenario is deployed to run the simulations and to measure bandwidth, consumption of resources (i.e., CPU cycles and bandwidth usage) and communication latency. Additionally, the trade-off between security and performance is discussed measuring the bandwidth overhead and the consumption increase associated to secure the communications. Different ciphering and authentication algorithms are tested, following the recommendations made by the Internet Engineering Task Force (IETF).

The Internet of Engineering Task (IETF) developed a lighter application protocol (Constrained Application Protocol (CoAP)) for the constrained IoT devices operating in lossy environments. Based on UDP, CoAP is a lightweight and efficient protocol compared to other IoT protocols such as HTTP, MQTT, etc. CoAP also provides reliable communication among nodes in wireless sensor networks in addition to features such as resource observation, resource discovery, congestion control, etc. These capabilities of CoAP have enabled the implementation of CoAP in various domains ranging from home automation to health management systems. The use of CoAP has highlighted its shortcomings over the time. To overcome shortcomings of CoAP, numerous enhancements have been made in basic CoAP architecture. This survey highlights the shortcomings of basic CoAP architecture and enhancements made in it throughout the time. Furthermore, existing challenges and issue in the current CoAP architecture are also discussed. Finally, some applications with CoAP implementation are mentioned in order to realize the viability of CoAP in real world use cases.

In Internet of Things (IoT) networks, devices use various application protocols, such as MQ telemetry transport (MQTT), constrained application protocol (CoAP), and extensible messaging and presence protocol (XMPP). However, because of the various protocols used, devices adopting different protocols cannot communicate mutually; thus, service interoperability issues arise. To enhance service interoperability, protocol conversion is required. Because different protocols are used in IoT networks, they are required to correspond to various protocols and have high extensibility for protocol conversion. In this paper, a protocol conversion method that satisfies these requirements is proposed. The proposed method converts packets into a middle format before converting them into target protocols. Conversion rules are described for each protocol; thus, the proposed method has high extensibility. We confirmed that clients that use the proposed conversion method could successfully connect to other devices using different protocols and communicate mutually through servers. The protocols included MQTT, CoAP, XMPP, and SMTP. Furthermore, the throughput degradation caused by the conversion process is small.

The number of connected IoT devices deployed globally is increasing at a tremendous rate. The IoT has a wide range of application domains providing extensive IoT-based services. The basic idea is to deliver a new set of applications where smart devices collaborate without any human interference. The variability and visibility of IoT based services lead to the development of the full spectrum of protocols. With the exponential growth of applications, it is essential to analyze the existing application layer protocols being used to exchange information among devices. In this paper, a detailed analysis of existing popular application layer protocols like Constrained Application Protocol (CoAP), Message Queue Telemetry Transport (MQTT), Advance Message Queuing Protocol (AMQP), Extensible Messaging and Presence Protocol (XMPP), etc. has been done to categorize them based on well-known properties such as architecture, energy consumption, reliability, QoS, and security aspects.

Wireless Sensor Networks (WSNs) consist mainly of resource constrained sensor nodes and gateways. Therefore, various lightweight communication protocols are emerging for Machine to Machine (M2M) communications. Among the various application layer protocols for data communication in WSNs, the two most popular protocols for constrained devices are the Message Queue Telemetry Transport Protocol (MQTT) with a variant for sensor nodes (MQTT-SN) and the Constrained Application Protocol (CoAP). Studies have shown that the performance of these different protocols are dependent on different network conditions. CoAP is more efficient in terms of message overhead and MQTT-SN is more efficient in terms of client complexity. Studies have further emphasized the levels of difficulties to implementing any of these protocols with regard to application requirements. In this paper we propose a hybrid MQTT-CoAP protocol technique using an abstraction layer that enables both MQTT-SN and CoAP protocol to be used in the sensor node. Performance evaluation of these protocols under the hybrid technique shows that the hybrid is feasible and while CoAP performs better in terms of energy consumption, the two protocols perform almost equally in latency. The observed values of latency and energy consumption in the developed hybrid technique was comparable to other studies.

Internet of things (IoT) is an imminent technological platform to overcome social and economic challenges. IoT devices are connected through internet technology using lossy communication links. IoT technologies such as Routing Protocol for low power and lossy networks (RPL), low power wireless personal area network (LoWPAN), the constrained application protocol (CoAP) CoAP/CoAPs comprises of low bandwidth and limited resources. RPL security is a big concern where the number of attacks may disrupt network communication. The sinkhole is one of routing attack which can damage network topology. We proposed a method for multisink network topology to detect rank and sinkhole attack. Single sinkhole attack detection technique is already existing. Our solution detects rank and sinkhole attack in multisink nodes scenario with multipath and less energy consumption. We used the Cooja simulator in Contiki Operating System to implement and evaluate the performance of our proposed technique.

The research into wireless communication and mobile computing is called to formulate novel smart mobility solutions to improve the quality of a citizen's life in smart cities. In such a context, in this paper we elaborate on the role of technologies like multi-access edge computing (MEC), Internet of Things (IoT) messaging protocols, such as Constrained Application Protocol (CoAP) and Message Queue Telemetry Transport (MQTT), and virtualization (i.e., digital twins) in the design of a framework enabling the collection and processing of data about the mobility of commuters and public transport vehicles. Such data have the purpose to feed mobility monitoring and transport planning solutions. A Proof-of-Concept (PoC) is developed to validate the framework under realistic experimental settings. Results in terms of efficiency and effectiveness of the considered messaging protocols are reported.

great variety of sensors and actuators are organized in Internet of Thing (IoT). The Constrained Application Protocol (CoAP) is one protocol supporting resource constrained devices and easy integration with the TCP/IP standards. In this paper we present a novel approach and a new framework to use CoAP group communication to implement configurable virtualized Sensors in Cyber-Physical computing environment. Experiments show that the framework can supply the reliable communications in Cyber-Physical system, minimize the consumption of WSN as well. It offers an extremely high efficiency communication way for event-based message exchange application, and provides a customizable filtering mechanism for data sampling.

The Internet of Things (IoT) now thoroughly suffuses our world, building on network communication and software technologies to increasingly interconnect sensors and actuators for unprecedented data collection. Yet, massively distributed IoT systems may be isolated in traditional intranets, creating unnecessary redundancy between different organizations that fulfill the same functions. To address these issues and develop an IoT Search Engine that can fully cope with the challenges of modern IoT deployment, in this paper we propose an IoT search engine platform using Python-based COAP (Constrained Application Protocol) which can discover and subscribe IoT sensors within the coverage of IoT search engine gateways. The search engine can retrieve data from sensors of different IoT systems, which we demonstrate using a traffic dataset to simulate autonomous vehicle queries. Our implementation also includes two designed algorithms to demonstrate mechanisms for data and data optimization.

The Constrained Application Protocol (CoAP) is a representative messaging protocol for Internet of Things (IoT) applications. It is noted that a lot of IoT-based streaming applications have been recently deployed. Typically, CoAP uses User Datagram Protocol (UDP) as its underlying protocol for lightweight messaging. However, it cannot provide reliability, since it is based on UDP. Thus, the CoAP over Transmission Control Protocol (TCP) was recently proposed so as to provide reliability. However, the existing schemes do not provide the error handling and flow controls suitably for IoT-based streaming applications. This tends to induce throughput degradation in wireless lossy networks. In this paper, we propose a CoAP-based streaming control (CoAP-SC) scheme, which is an extension of CoAP over UDP with error handling and flow control for throughput enhancement. The proposed CoAP-SC scheme is designed by considering the sequence number of data message, the use of ACK messages, and the buffer size of sending buffer. To do this, a new CoAP option is defined. For performance analysis, the proposed scheme is implemented and compared with the existing schemes. From the testbed experimentations in various network environments, we see that the proposed CoAP-SC scheme can provide better throughput than the existing CoAP-based schemes by performing the error handling and flow control operations effectively.

With the growth of Internet of Things (IoT), users develop many different IoT applications in web cloud platforms. However, cloud-based web services do not usually apply to the constrained networks because of HyperText Transfer Protocol (HTTP). In addition, distributed mechanisms to achieve identity authentication or data confidentiality are becoming more and more important when the number of devices located in IoT networks increases. The paper proposes the IoT Framework based on IoTtalk. IoTtalk is a web platform for users to quickly develop IoT applications. To enhance the applicability of IoTtalk in IoT networks and support identity authentication as well as data confidentiality, we introduce CoAP-based IoT Proxy and smart contract-based IoT Chain respectively. The IoT Proxy promotes the applicability of IoTtalk in IoT networks through the Constrained Application Protocol (CoAP). The IoT Chain provides identity authentication as well as data confidentiality to IoTtalk through the blockchain and the smart contract. Our experiments show that the IoT Framework promotes the security of the IoTtalk and keeps the performance of IoTtalk.

Internet of Things (IoT) is a system of interrelated devices with communication capabilities. Network congestion increases as the number of devices increase in the system and de-grades the Quality of Service (QoS). Unlike traditional Internet, TCP is not the de facto transport protocol for IoT because of the constrained nature of IoT devices. Therefore, congestion control mechanisms are coupled with application protocols, such as the Constrained Application Protocol (CoAP). Although there have been efforts to use CoAP with TCP, it typically uses UDP for data transport. CoAP defines a conservative congestion control mechanism that uses a fixed Retransmission TimeOut (RTO) for retransmissions regardless of the network conditions (e.g., Round Trip Time (RTT)). The Eifel Retransmission Timer is a popular algorithm originally proposed for TCP. It assesses prevalent network conditions by measuring RTT and accordingly sets the TCP RTO. This paper proposes to leverage the benefits of Eifel Retransmission Timer by integrating it with CoAP (when used with UDP) to obtain better RTO estimates and control congestion. The proposed algorithm is named as CoAP-Eifel. The effectiveness of the proposed approach has been validated by comparing it with the standard RTO estimation technique of CoAP. The experiments are carried out in a real testbed by using FIT/IoT-LAB. The results demonstrate that the proposed approach provides a better trade-off in terms of delay and throughput, without affecting the packet delivery ratio.

IoT-based applications operate in a client–server architecture, which requires a specific communication protocol. This protocol is used to establish the client–server communication model, allowing all clients of the system to perform specific tasks through internet communications. Many data communication protocols for the Internet of Things are used by IoT platforms, including message queuing telemetry transport (MQTT), advanced message queuing protocol (AMQP), MQTT for sensor networks (MQTT-SN), data distribution service (DDS), constrained application protocol (CoAP), and simple object access protocol (SOAP). These protocols only support single-topic messaging. Thus, in this work, an IoT message protocol that supports multi-topic messaging is proposed. This protocol will add a simple “brain” for IoT platforms in order to realize an intelligent IoT architecture. Moreover, it will enhance the traffic throughput by reducing the overheads of messages and the delay of multi-topic messaging. Most current IoT applications depend on real-time systems. Therefore, an RTOS (real-time operating system) as a famous OS (operating system) is used for the embedded systems to provide the constraints of real-time features, as required by these real-time systems. Using RTOS for IoT applications adds important features to the system, including reliability. Many of the undertaken research works into IoT platforms have only focused on specific applications; they did not deal with the real-time constraints under a real-time system umbrella. In this work, the design of the multi-topic IoT protocol and platform is implemented for real-time systems and also for general-purpose applications; this platform depends on the proposed multi-topic communication protocol, which is implemented here to show its functionality and effectiveness over similar protocols.

The goal of this work is to design and implement a weather station prototype which can monitor and collect weather data. The weather station used Arduino board and other devices which have ability to measure temperature, humidity, wind speed and direction, ozone gas, atmospheric pressure and rainfall data. The system focused on wide range of IoT devices, inexpensive, endurance of battery life, and connection density. Therefore, Narrowband Internet of Things network (NB-IoT) will be used to transfer data to MySQL database server via Constrained Application Protocol (CoAP). Received data can be displayed using Grafana (Open source visualization and analytics software) on a personal computer. Thus, this system will be very beneficial for many who depend on weather data as part of their everyday lives.

The growth of the Internet of Thing (IoT) results in an expanded attack that requires end-to-end security techniques. IoT applications involve in a business-oriented such as insurance and banking, and mission-critical crisis such as e-health and intelligent transportation systems. One of the most protocols commonly used for resource discovery in IoT is the Constrained Application Protocol (CoAP) protocol which fits the constrained devices. There is a need for security support in CoAP for the IoT environment. This paper presents a security approach using TACACS+ to strengthen the security of CoAP. The proposed security mechanism separately supports access control, authentication, and accounting. It has been implemented using a mobile phone and a Raspberry Pi. The mobile phone is used as a client, and the Raspberry Pi is used as a server. The implementation composes of a TI SensorTag and a WeMo switch that are used as resources. This paper, also, presents performance indexes of the security technique in terms of CPU usage, time computation, latency, energy consumption, and traffic exchange between a client and a server. The experimental results show the proposed method is compatible with IoT devices.

Sensing devices are expected to interconnect over large geographical areas and federations of wireless sensor networks are expected in a near future. In such environments a critical issue is how to discover the resources available at devices in a scalable manner. For this purpose, a Constrained Application Protocol (CoAP) Usage for REsource LOcation And Discovery (RELOAD), a generic self-organizing Peer-to-Peer (P2P) overlay network service, has been defined to be used as a lookup service, to store available device resources and as a cache for sensor data. Each P2P resource, at the RELOAD/CoAP overlay, includes references to device resources, hosted at one or more constrained nodes, but no provision is made for the insertion of bindings/references to P2P resources already available at the P2P overlay network. Such feature would increase the efficiency and consistency of storage, avoiding duplicate references, a very relevant issue for future IoT applications relying on the federation of wireless sensor networks. In this article an extension to the service provided by CoAP Usage is proposed so that resource bindings can be managed. Two binding models, and a heuristic algorithm for their implementation, are proposed. Results show that such models lead to a better resource organization, reducing the number of sensor resource entries and/or fetches to the P2P overlay. FCT (Foundation for Science and Technology) from Portugal within CEOT (Center for Electronic, Optoelectronic and Telecommunications) [UID/MULTI/00631/2013] info:eu-repo/semantics/publishedVersion

GraphQL can be used for reducing delays and energy consumption in duty cycled wireless sensor networks (DC-WSNs) in Internet of Things (IoTs) deployments. The authors evaluate GraphQL for DC-WSN based IoTs and Web of Things applications over Constrained Application Protocol (CoAP) and Hyper Text Transfer Protocol (HTTP), respectively.

Precision Agriculture (PA), as the integration of information, communication and control technologies in agriculture, is growing day by day. The Internet of Things (IoT) and cloud computing paradigms offer advances to enhance PA connectivity. Nevertheless, their usage in this field is usually limited to specific scenarios of high cost, and they are not adapted to semi-arid conditions, or do not cover all PA management in an efficient way. For this reason, we propose a flexible platform able to cope with soilless culture needs in full recirculation greenhouses using moderately saline water. It is based on exchangeable low-cost hardware and supported by a three-tier open source software platform at local, edge and cloud planes. At the local plane, Cyber-Physical Systems (CPS) interact with crop devices to gather data and perform real-time atomic control actions. The edge plane of the platform is in charge of monitoring and managing main PA tasks near the access network to increase system reliability against network access failures. Finally, the cloud platform collects current and past records and hosts data analytics modules in a FIWARE deployment. IoT protocols like Message Queue Telemetry Transport (MQTT) or Constrained Application Protocol (CoAP) are used to communicate with CPS, while Next Generation Service Interface (NGSI) is employed for southbound and northbound access to the cloud. The system has been completely instantiated in a real prototype in frames of the EU DrainUse project, allowing the control of a real hydroponic closed system through managing software for final farmers connected to the platform.

The Internet of Things (IoT) is considered a milestone for the realization of intelligent services through the interaction of smart things. Constrained application protocol (CoAP) was proposed by the Internet engineering task force as a web transfer protocol in the IoT. CoAP inherits the properties of the representational state transfer model to realize communications with low overhead. It is characterized by a small overhead and it uses the stateless UDP protocol in the transport layer. As the IoT has attracted more attention, the demands for various multimedia applications based on the IoT have increased. Video applications and IoT objects communicate through CoAP. CoAP defines a simple congestion control mechanism that can provide reliable communication between IoT endpoints. However, the congestion control mechanism was not proposed considering video streaming applications. In this paper, we evaluate the performance of video streaming applications for reliable CoAP communications between devices over a wireless network. To evaluate the performance, we perform multiple experiments by adjusting the CoAP transmission parameters. Moreover, we analyzed the effect of the segment duration of a video being streamed over CoAP. The results show that the default CoAP parameters do not fulfill the stringent Quality of Experience constraints. The experiments show that the default retransmission RTO is extremely high for the video streaming application. A small increase in the packet loss can significantly affect the video download time which increases the risk of playback interruption. Through experiments, we show that the performance of video streaming applications can be improved by tuning the congestion control parameters according to the network conditions. A smaller RTO value can ensure significant reduction in the segment download time. Similarly, the video can be downloaded quickly by increasing the number of unacknowledged transactions. Furthermore, the experiments show that the risk of playback interruption can be mitigated by downloading longer segments.

The Constrained Application Protocol (CoAP) has been widely used, as the number of embedded sensors or devices increases. To support mobility management in web based Internet-of-Things environment is critical issue. For this purpose, a CoAP-based mobility management protocol, named CoMP has been proposed, but this protocol was designed for a single sensor node mobility. However, it does not perform well in group-based mobility. To overcome this limitation, we propose a CoAP-based group mobility management protocol, named CoMP-G. In the proposed scheme, one of the body sensor will function as a coordinator and it will exchange all the control messages with web-of-things mobility management system (WMMS) on behalf of other body sensors. Besides, each WMMS maintains the information of the group of body sensors. From the numerical analysis, we proved that the proposed scheme gives the best performance in terms of total signaling and handover delay from the existing CoMP protocol.

In the near future, Internet of Things (IoT) will play a relevant role in people’s lives and one of the main challenges will be the integration of heterogeneous networks. Among widely adopted network technologies, the development of the so-called Low-Power Wide-Area Networks (LPWANs), in particular Long Range WAN (LoRaWAN) is attracting a significant interest from both academic and industrial worlds. The integration of LoRaWAN with other communication technologies represents a fundamental requirement for a successful rapid and large-scale diffusion of IoT paradigms, such as Smart Farming, Smart Factory, and Smart City. The aim of this paper is two-fold: we propose (i) a mechanism for automatic discovery of the sensors a LoRa device is equipped with; and (ii) a novel networking architecture, based on cloud computing and node virtualization, to enable the interaction of LoRaWAN end-nodes with other IP-based IoT devices. Our solution does not impact LoRaWAN networking and enables a seamless interaction between LoRaWAN end-nodes and other Constrained Application Protocol (CoAP)-based nodes.

Due to the heterogeneity, high cost, and harsh environment, ocean observatories demand a flexible, robust, and capable scheme to integrate science instruments. To deal with the challenges of automatic instrument integration and machine-to-machine interaction in ocean observatories, a systematic scheme is proposed based on Zero Configuration Networking (Zeroconf), Programmable Underwater Connector with Knowledge (PUCK), Constrained Application Protocol (CoAP), and Message Queuing Telemetry Transport (MQTT) protocols, as well as a smart interface module to achieve instrument plug-and-play and standard communication among heterogeneous ocean instruments. The scheme specifically considers the resource-constrained ocean observatories and machine-to-machine interoperability, which is of great significance to interoperable ocean observatories. The laboratory tests have verified the feasibility of the proposed scheme.

IoT is a network of connected objects in which these objects can collect data and exchange them using embedded sensors. It permits communication between objects and things, and it binds together units in our universe under a regular infrastructure. It allows not just controlling things around us, but also keeping us educated on the state things. Internet of Things (IoT) devices are used in daily life in many domains such as health, agriculture and many others. In the IoT world, the embedded sensors of connected devices play a major role. These sensors have limited energy capabilities, and any network of such devices is called Low power and Lossy network (LLNs). Many implementations and techniques have been trying to address this issue of energy consumption. This paper focuses on Application Layer techniques and specifically on one of the most important protocols, the Constrained Application Protocol (CoAP). We discuss ten of the best energy-efficient techniques to implement the CoAP, and conduct a comparison among these techniques on different levels.

Internet of things (IoT) and Fog computing applications deal with sensitive data and need security tools to be protected against attackers. CoAP (Constrained Application Protocol), combined with DTLS (Datagram Transport Layer Security), provides security to IoT/Fog applications. However, processing times need to be considered when using this combination due to IoT/Fog environment constraints. Our work presents a CoAP with DTLS application and analyzes the performance of Raspberry Pi 3 during DTLS handshakes, data encryption and data decryption with the most relevant cipher suites. The performance of confirmable and non-confirmable CoAP POST requests is also measured and discussed in our work. We discovered that cipher suites that use RSA as an authentication method on handshake are slightly faster than cipher suites that use ECDSA, while symmetric key encryption with AES256(128)GCM are 40% faster than AES256(128) default modes. Our study also suggests CoAP modifications to obtain higher efficiency, and it might help future IoT/Fog application developers to understand CoAP and DTLS union, providing an application example and performance metrics.

The presence of Constrained Application Protocol (CoAP) proxies may lead to infinite forwarding loops, which is undesirable. To prevent and detect such loops, this document specifies the Hop-Limit CoAP option.

The Constrained Application Protocol (CoAP) is a lightweight protocol specially designed to support constrained Internet of Things (IoT) devices and networks having limited bandwidth. The current growth of IoT market means more sensors in the networks and increased network traffic congestion. Since IoT clients prefer servers whose sensor values have been simultaneously updated it is of paramount importance that servers be highly efficient in synchronizing message updates from its sensors. Our research however, finds the legacy CoAP not optimally efficient in that it introduces network traffic and message duplication hence consuming extra bandwidth. We propose a new Set theory scheme that optimizes synchronized message delivery in IoT by reducing the number of duplicated messages. Our proposed scheme eliminates unnecessary duplicated messages, hence reducing network traffic. On comparing the number of messages sent by servers, our scheme outperformed the legacy CoAP by up to a 50% reduction in the number of messages sent.

This memo defines application/multipart-core, an application- independent media-type that can be used to combine representations of zero or more different media types into a single message, such as a CoAP request or response body, with minimal framing overhead, each along with a CoAP Content-Format identifier.

The Constrained Application Protocol (CoAP) is an IETF standard application protocol for the future Internet of Things (IoT). Since IoT devices are often interconnected by networks characterized by high packet error rates and low throughput, congestion control will be crucial to ensure proper and timed communication in these networks. Therefore, CoCoA+, an advanced congestion control algorithm for CoAP, is currently being specified by the IETF. In this work, we present a critical analysis of CoCoA+ performance and highlight some of its shortcomings and pitfalls. Two different scenarios are considered: one with an increasing traffic load due to an increasing number of CoAP requests, and another with an interfering traffic concurrently transmitted in the network characterized by a bursty pattern. In the former scenario, we show how CoCoA+ may be characterized by many spurious retransmissions at some offered loads close to congestion. In the latter, we show instead how the weak estimator is not particularly effective in adapting to changing traffic loads. In order to overcome such limitations, a number of modifications to CoCoA+ are proposed. The resulting solution, named precise Congestion Control (pCoCoA), is shown to reduce the number of retransmissions, while guaranteeing throughputs and delays comparable to those of CoAP and CoCoA+.

The Constrained Application Protocol (CoAP) has been widely used, as the number of embedded sensors or devices increases. To support mobility management in web based Internet-of-Things environment is critical issue. For this purpose, a CoAP-based mobility management protocol, named CoMP has been proposed, but this protocol was designed for a single sensor node mobility. However, it does not perform well in group-based mobility. To overcome this limitation, we propose a CoAP-based group mobility management protocol, named CoMP-G. In the proposed scheme, one of the body sensor will function as a coordinator and it will exchange all the control messages with web-of-things mobility management system (WMMS) on behalf of other body sensors. Besides, each WMMS maintains the information of the group of body sensors. From the numerical analysis, we proved that the proposed scheme gives the best performance in terms of total signaling and handover delay from the existing CoMP protocol.

In the renowned Internet of Things (IoT) networks, it is expected a vast number of devices with IP connectivity and constrained capabilities. Due to reduced resources they are the target of different type of attacks and providing security has become a basic pillar for the success and evolution of IoT. Among the specific key security aspects are the authentication, access control and key distribution for data protection. In particular, all these aspects are included in the process of bootstrapping , which allows a Smart Object to join a network domain in a secure fashion. This process, which indeed involves authentication, authorization, and key distribution, typically requires communication between the smart object and an entity, the Controller , in charge of steering the bootstrapping process within the network’s domain. However, direct communication between both might be impeded, e.g., when the entity is unreachable by radio, or the smart object does not have a routable IP address until it is successfully authenticated and authorized to join the network. A common solution is to use an intermediate entity (the Intermediary ) to aid in this task. For example, the ZigBee IP standard defines a relay for the protocol for carrying authentication for network access (PANA). Moreover, the IETF is exploring the use of an intermediary to help this process. In this paper, we analyze, explore, and design an intermediary based on constrained application protocol (CoAP). We pay attention to the authentication with the extensible authentication protocol (EAP) and CoAP, which has resulted in a more constrained alternative to PANA for EAP-based bootstrapping in IoT. Nevertheless, our design of the CoAP-based intermediary is so general that it is independent of the authentication protocol in use. In particular, we have analyzed as intermediary the usage of a CoAP proxy , as defined in the CoAP standard; alternatively we have introduced the concept of the CoAP relay and CoAP stateless proxy . We evaluate the performance of each solution and we compare between them and with PANA relay.

The datagram transport layer security (DTLS) is a de facto standard for the end-to-end security of the constrained application protocol (CoAP) that defines the following three security modes: preshared key (PSK), raw public key, and certificate. The pros and cons of each security mode are obvious. Even though the PSK mode is the most preferable in terms of the performance of the DTLS handshake, the in-advance distribution of a unique symmetric key for each pair of endpoints is difficult as the number of pairs increases. Alternatively, the certificate mode provides a convenient key-management functionality but its performance is very poor. The focus of most of the previous works is the reduction of the computational load for a single DTLS handshake that is induced by the certificate mode. In this paper, a group-oriented end-to-end security is considered, together with the introduction of a new security mode. Namely, a security association is established between a CoAP client and a group of CoAP servers (sensor devices); however, a fine-grained access control can be enforced so that each CoAP client can access a limited number of CoAP servers in the group. Furthermore, when each CoAP client performs several DTLS handshakes with the CoAP servers in the group, the first DTLS handshake involves a single public-key operation. A public-key operation, however, is not required for the subsequent DTLS handshakes, so the overall computational burden can be reduced. Also, a testbed was established along with the implementation of the proposed security mechanism for the conduction of a performance comparison with the other security mechanisms. Note to Practitioners —Datagram transport layer security (DTLS) is a standards-based security protocol to secure communications in an IoT environment, including home, factory, or building automation systems. However, to develop a practical security solution based on DTLS, several assumptions inherent to DTLS need to address the practical requirements of various IoT scenarios. Furthermore, some barriers associated with implementing DTLS in an IoT environment should be overcome. This paper presents an interface to extend the basic security functionalities provided by DTLS. Through the interface, a general security platform can be constructed and combined with DTLS. Hence, fine-grained access control and group security can be merged with DTLS, together with standards compliance.

In this paper, we consider Internet of Things (IoT) domain running multicasting constrained application protocol (CoAP) over IEEE 802.15.4 network ended by CoAP proxy/cache. We examine the features of CoAP multicasting in order to ensure freshness of data in the cache as a function of the leisure parameter which allows devices to reply in arbitrary (random) time periods after receiving multicast GET request. We also investigate communication delay in the IoT domain and daily energy consumption of devices under several leisure schemes which may be implemented at the application level or at the medium access control layer. The impact of the leisure parameter appears to be critical for congestion avoidance. We show that a combination of proactive and reactive cache update with appropriate multicast leisure scheme can achieve low probability of outdated data while limiting the energy expenditure of nodes to a satisfactory value. Furthermore, best performance with respect to delay is obtained when the leisure period is integrated in the CSMA/CA backoff process.

With industrialization and continuously evolving climatic conditions, the urge to practice agriculture with the fusion of technology has become a necessity. In the era of Internet of Things where all eyes are witnessing the evolution of machine to machine interaction, there is also a lack of clarity in considering the type of protocol to be used in building a particular system like Green House. A green house is a regulated environment for agriculture where critical parameters like temperature, light, humidity, ph level of soil can be monitored with the help of sensor systems using Internet of Things protocols. Message Queue Telemetry Transfer protocol was chosen over Constrained Application Protocol and Extensible Messaging and Presence Protocol in the experiment conducted in terms of its light weight transmission, resource consumption and effectively providing the different quality of services to detect the temperature and humidity as well as the gas leaks encountered in a greenhouse environment.

The constrained application protocol (CoAP) observe feature has the potential to achieve fast communication and low energy consumption. We have analyzed a CoAP proxy which stores observed data from multiple Internet of Things (IoT) nodes that belong to single IoT domain. To maintain the freshness of cached records under random data arrivals, we have implemented the evaluation of Max-Age parameter at the proxy. We have also implemented congestion control at both IoT nodes and proxy, and show that it interacts with data freshness estimation at the proxy. Our results demonstrate the capacity limits of a single IoT domain against cluster size, interobservation time, proxy re-registration rate, ratio of confirmable/nonconfirmable observations, and presence of congestion control.

Internet of Energy (IoE) is a subset of the Internet of Things which covers all aspects of electrical energy systems and provides secure connectivity and interoperability between power grid and Internet. In this paper, we present a fog-based IoE architecture for transactive energy (TE) management systems. The proposed design consists of three different layers. In the first tier, home gateways are employed which collect customers energy consumption data and provide necessary interface between customers and power grid. In the second layer, there are some local fog nodes located at the network edge and provide services with low latency. From the TE system point of view, the fog node act as retail energy market server which provides energy services to the end users. In the third layer, cloud servers are utilized to provide permanent and reliable data storage and high computing power. The proposed architecture supports different communication protocols such as hypertext transfer protocol, constrained application protocol, and OpenADR. We calculate the required bandwidth and delay performance of both fog- and cloud-based models. We present an optimal day ahead energy consumption schedule and an intercustomer energy trading mechanism for exchanging energy between end users. The performance of the proposed architecture is evaluated in terms of different power grid and communication network metrics. Results confirm the superiority of the proposed architecture.

We propose to apply constrained application protocol publish/subscribe to cache popular Internet of Things (IoT) resources in a broker to reduce the energy consumption of servers (which host these popular resources) and the average delay for delivering the IoT resources’ contents to the clients. We provide the smart parking application in smart cities as an example to demonstrate the benefit for conducting popular IoT resource caching. However, caching popular IoT resources in the broker may not always be the optimal choice, i.e., the broker may be congested by caching too many IoT resources, and so the average delay for enabling the broker to deliver contents of the IoT resources may be unbearable. Thus, we propose a novel energy aware and latency guaranteed dynamic resource caching (EASE) strategy to enable the broker to cache suitable popular resources such that the energy savings from the servers are maximized, while the average delay for publishing the contents of the resources to the corresponding clients is minimized. We demonstrate the performances of EASE via simulations as compared to other two baseline IoT resource caching strategies.

The Semantic Web of Things (SWoT) integrates knowledge representation and reasoning techniques originally devised for the Semantic Web into Internet of Things architectures, in order to provide more advanced service/resource management and discovery. This paper proposes a novel SWoT framework, enabling collaborative discovery of sensors and actuators in pervasive contexts. It is based on a backward-compatible extension of the Constrained Application Protocol (CoAP), supporting advanced semantic matchmaking via non-standard inference services. The proposed mobile agent is able to discover devices and share smartphone embedded sensors in a peer-to-peer fashion. Efficient data stream mining is also integrated to analyze raw data gathered from the environment and detect high-level events, annotating them with machine-understandable metadata. Finally, a case study about cooperative environmental risk monitoring and prevention in Hybrid Sensor and Vehicular Networks is presented. Experimental performance results on a real testbed assess the approach.

Over the last few years, the Internet of Things (IoT) has grown in protocols, implementations and use cases. In terms of communication protocols, the Constrained Application Protocol (CoAP) prevails among the rest, such as MQ Telemetry Transport (MQTT) or Advanced Message Queuing Protocol (AMQP). This protocol is lightweight and capable of running in resource constrained devices and networks and can be securized using Datagram Transport Layer Security (DTLS). Having a secure channel of communication is important in IoT environments, since IoT devices affect the physical world and exchange personal private data. There exist many implementations of CoAP, each of these with its own particular features and requirements. Therefore, it is important to choose the CoAP implementation that suits better to the specific requirements of each application. This paper presents a feature and empirical comparison of several open source CoAP implementations and also analyzes the security libraries they use. First of all, it surveys current CoAP implementations, and compares them in terms of built-in core, extensions, target platform, programming language and interoperability. Then, a theoretical analysis of the security libraries is provided. Finally, it analyzes CoAP libraries’ performance in terms of latency, memory and CPU consumption in a real testbed deployed in an industrial scenario, in order to help in adopting a decision criterion for similar deployments.

Massive diffusion of constrained devices communicating through low-power wireless technologies in the future Internet of Things (IoT) will require in many scenarios the deployment of IoT gateways to allow applications to discover and access IoT resources. In this context, Fog/Edge computing will represent an opportunity to deploy IoT gateways in proximity of IoT domains, meeting the requirements of applications needing low-latency interactions with devices. In this paper, we present an edge-centric distributed architecture to provide resource discovery and access services to IoT applications. The proposed approach leverages the CoRE Resource Directory interface and the Constrained Application Protocol (CoAP) to expose a standard interface for global discovery and access. Multiple IoT gateways are federated through a peer-to-peer overlay implemented by a distributed hash table, which is exploited to share the information on IoT resources available across multiple domains. The proposed solution is validated by means of a small-scale prototype, and extensively evaluated through emulation in large scale deployment in comparison to a centralized Cloud-based approach. Experimental results demonstrated that the proposed approach guarantees lower latencies than a centralized solution and can ensure scalability for small to medium sized deployments.

Smart societies have an increasing demand for quality-oriented services and infrastructure in an industrial Internet of Things (IIoT) paradigm. Smart urbanization faces numerous challenges. Among them, secured energy demand-side management (DSM) is of particular concern. The IIoT renders the industrial systems to malware, cyberattacks, and other security risks. The IIoT with the amalgamation of big data analytics can provide efficient solutions to such challenges. This paper proposes a secured and trusted multi-layered DSM engine for a smart social society using IIoT-based big data analytics. The major objective is to provide a generic secured solution for smart societies in IIoT environment. The proposed engine uses a centralized approach to achieve optimum DSM over a home area network. To enhance the security of this engine, a payload-based authentication scheme is utilized that relies on a lightweight handshake mechanism. Our proposed method utilizes the lightweight features of the constrained application protocol to facilitate the clients in monitoring various resources residing over the server in an energy-efficient manner. In addition, data streams are processed using big data analytics with MapReduce parallel processing. The proposed authentication approach is evaluated using NetDuino Plus 2 boards that yield a lower connection overhead, memory consumption, response time, and a robust defense against various malicious attacks. On the other hand, our data processing approach is tested on reliable datasets using Apache Hadoop with Apache Spark to verify the proposed DMS engine. The test results reveal that the proposed architecture offers valuable insights into the smart social societies in the context of IIoT.

IoT group communication allows users to control multiple IoT devices simultaneously. A convenient method for implementing this communication paradigm is by leveraging software-defined networking (SDN) and allowing IoT endpoints to “advertise” the resources that can be accessed through group communication. In this paper, we propose a solution for securing this process by preventing IoT endpoints from advertising “fake” resources. We consider group communication using the constrained application protocol (CoAP), and we leverage Web of Things (WoT) Thing Description (TD) to enable resources’ advertisement. In order to achieve our goal, we are using linked-data proofs. Additionally, we evaluate the application of zero-knowledge proofs (ZKPs) for hiding certain properties of a WoT-TD file.

WSN have limitations that make them difficult to apply in critical and large-scale scenarios. The main identified barriers are the difficulty of building the management system, and their lack of flexibility to adapt to policy changes. Software defined networking (SDN) is a viable alternative to solve these limitations. Besides, SDN can bring several other benefits to WSN, allowing, for example, complex network applications to run on the controller. A new approach called software-defined wireless sensor network (SDWSN) is increasing in interest by the research community, and in this paper, we propose a new SDWSN control plane based on the constrained application protocol (CoAP). We provide a comprehensive specification for the control plane, including the communication infrastructure, the control plane protocol, and the basic networking functions in controllers (topology discovery and flow control). We show how the proposed control plan can be implemented in the Contiki operating system and present a preliminary performance evaluation of the overhead introduced by the control plane protocol.

Constrained Application Protocol (CoAP) has become the de-facto web standard for the IoT. Unlike traditional wireless sensor networks, Internet-connected smart thing deployments require security. CoAP mandates the use of the Datagram TLS (DTLS) protocol as the underlying secure communication protocol. In this paper we implement DTLS-protected secure CoAP for both resource-constrained IoT devices and a cloud backend and evaluate all three security modes (pre-shared key, raw-public key, and certificate-based) of CoAP in a real cloud-connected IoT setup. We extend SicsthSense– a cloud platform for the IoT– with secure CoAP capabilities, and compliment a DTLS implementation for resource-constrained IoT devices with raw-public key and certificate-based asymmetric cryptography. To the best of our knowledge, this is the first effort toward providing end-to-end secure communication between resource-constrained smart things and cloud back-ends which supports all three security modes of CoAP both on the client side and the server side. SecureSense– our End-to-End (E2E) secure communication architecture for the IoT– consists of all standard-based protocols, and implementation of these protocols are open source and BSD-licensed. The SecureSense evaluation benchmarks and open source and open license implementation make it possible for future IoT product and service providers to account for security overhead while using all standardized protocols and while ensuring interoperability among different vendors. The core contributions of this paper are: (i) a complete implementation for CoAP security modes for E2E IoT security, (ii) IoT security and communication protocols for a cloud platform for the IoT, and (iii) detailed experimental evaluation and benchmarking of E2E security between a network of smart things and a cloud platform. Funding details: VINNOVA; Funding text: This research has partly been funded by the Strategic Innovation Program for Internet of Things (SIP-IoT), a joint venture of VINNOVA, Formas och Energimyndigheten; and partly by the EU H2020 project NobelGrid under grant no. 646184.CEBOT;NOBELGRIDVINNOVA;EU, Horisont 2020

Wireless sensor and actuator networks (WSAN) have greatly benefited from the latest development in real-time Internet of Things standardisation efforts. Specifically, the Internet Engineering Task Force Constrained Application Protocol (CoAP) is one of the preferred mechanisms that provide session transport in the context of low-power low-rate networks in general and WSAN in particular. CoAP, that relies on traditional user datagram protocol, introduces a particular mode of operation, known as non-confirmable, that minimises latency but it is highly sensitive to network packet loss. The use of forced forward error correction (FEC), although efficient at reducing packet loss, excessively increases the session throughput. The authors introduce an algorithm that dynamically manages FEC minimising application layer packet loss while keeping throughput under control. The mechanism is evaluated through an experimental framework where traditional CoAP, forced FEC CoAP and dynamic FEC CoAP implementations are compared.

The Internet of Things (IoT) has emerged as the key networking paradigm for supporting the connectivity of massively distributed objects and numerous simultaneous applications. The constrained application protocol (CoAP) is designed to meet the requirements for IoT data transmission among constrained nodes. The lean design of CoAP enables it to additionally meet the needs of the data transmission in dynamic network environments. In this paper, we conduct an emulation-based quantitative performance assessment of CoAP in comparison with HTTP, assessing data transmission based on key characteristics of dynamic network environments and the designed scenarios. We also designed scenarios and evaluate the performance of investigated protocols using real-world IoT datasets. Our experimental results demonstrate that CoAP performs better than HTTP for data transmission in the dynamic network environments with respect to delivery rate, delay, and overhead. In addition, we analyze the impact of features in dynamic network environments on the performance of data transmission protocols with respect to success rate, delay and overhead, as well as discuss some further extensions for future research.