Communication protocols

In this paper, we present and compare existing IoT application layer protocols as well as protocols that are utilized to connect the “things” but also end-user applications to the Internet. We highlight IETF’s CoAP, IBM’s MQTT, HTML 5’s Websocket among others, and we argue their suitability for the IoT by considering reliability, security, and energy consumption aspects. Finally, we provide our conclusions for the IoT application layer communications based on the study that we have conducted.

This paper is an introduction to Real-Time Networks (RTNs) and to the literature on them. RTNs are a fundamental model of computation that consists of a collection of parallel 'activities' (i.e. single-threaded processes with internal state) which only communicate along explicit paths, each of which imposes a specific protocol. RTNs have underpinned various software design notations, such as MASCOT and DORIS, and RTNs are still often used by software architects when designing real-time software in other notations, such as UML. Important transferable concepts from MASCOT-3 and DORIS are introduced , including a rich family of predefined formalised RTN protocols. Sophisticated asynchronous implementations have been developed for the 'pool' protocol, making implementations of it possible which minimise the temporal interference between different parts of a system. Various formal analysis techniques have been taxed in showing the validity of these implementations. In particular, Simpson's 4-Slot asynchronous communication mechanism (ACM) has received extensive academic attention, and the conflicting results of this work have led to insights into how to classify ACMs; the importance, when modelling ACMs, of taking into account the way that the metastability phenomenon in asynchronous circuits is min-imalised; and the dangers and limitations of the 'atomicity' abstraction when specifying asynchronous protocols. Other formalisation and analysis techniques that have been developed for RTNs are described, including: ADL, a activity formal specification language; and SHARD, a hazard analysis technique for RTNs. It is explained why notations based on the synchrony hypothesis (such as Statecharts) are inadequate for specifying the behaviour of arbitrary RTN systems, and alternative proposals are introduced, including: Mode-machines; Transactions; and Interactions. Finally, RTNs are compared with the currently reigning 'OO' design paradigm, and it is argued that RTNs embody a sophisticated concurrent object-oriented computational paradigm that has yet to be fully appreciated by many OO software architects. RTNs and dynamic reconfigurable systems are briefly discussed.

CANopen serves as one of the few truly independent communication protocols open to customization and interfacing of various technologies on multiple networks. This report introduces the basic structure of CANopen and its advantages. It also discusses examples of its myriad applications and its future prospects in a fast developing world.

Integrating modern aircraft stores, particularly weapons, creates a complex system of systems challenge. The traditional approach to such integrations was for each to be a stand-alone program. For each program a unique interface would usually be implemented, usually also with a set of unique problems, such as the missile ‘ghosting’ problems experienced during the F-16 to AMRAAM integration (Ward 1993). In response to the problems of such an approach MIL-STD-1760 an Interface Standard for Aircraft to Store Electrical Interconnection System was released by the US DoD to standardise aircraft/store interfaces. This paper discusses the advantages and limitations of the architectural techniques of MIL-STD-1760. A hierarchical method for integrating the use of the standard into a safety case is also described.

Keywords: Safety, architecture, software, MIL-STD-1760.

At present most of the organizational Information systems are formed using several heterogeneous distributed systems. Relevant information might be maintained in several distributed systems. “Openness” is the basic and the most important property of a distributed system for intercommunication. It describes how systems can be extended to be inter-operated with other systems. So many standards and protocols are developed for sharing data [1]. Among several available standards and protocols, Simple Object Access Protocol (SOAP) web-service is becoming popular [2]. However, these standards and protocols have limitations when it is necessary to transfer different formats of information between heterogeneous systems. The new protocol that is introduced in this research is based on human communication and conversation techniques. Rather than in system communication, human communication gives the upper hand for the two parties by enabling a meaningful communication exchange. This new protoc...

One of the main communication protocols used for transmitting PMU data packets are Transmission Control Protocol/ Internet Protocol (TCP/IP) and User Datagram Protocol/Internet protocol (UDP/IP). This paper aims at presenting the implementation and simulation of a communication network for wide area monitoring system. The main purpose is to send real data recorded from PMUs over communication network using both protocols and compare their performance in terms of data transmission reliability.

With the evolution of data communications in process control, network problems have taken on new proportions. The connections with a DCS and PLC system or from the plant network to the control network are vital to production, yet can be an invitation to problems. This paper looks at several real-life network disasters and discusses strategies for avoiding them. Solutions, including the use of VLANs (virtual local area networks), are discussed. A case history from a pulp and paper mill illustrates how a VLAN can be implemented to protect multiple DCS and PLC systems from each other and from business users.

—Distributed applications depend on application-layer communication protocols to exchange data among processes and coordinate distributed operations, independent of underlying communication subsystems and lower level protocols. Since such protocols are application-specific, developers often must invent or re-invent solutions to reoccurring problems involving sending and receiving messages to meet specific functionality, efficiency, distribution, reliability, and security requirements. This paper introduces a pattern language, called CommDP, consisting of nine design patterns that can help developers understand existing reusable solutions and how those solutions might apply to their situations. Consistent with other pattern languages, the CommDP patterns are described in terms of the problems they address, their contexts, and solutions. The problems and consequences of the solutions are evaluated against four desirable qualities: reliability, synchronicity, longevity, and adaptability for scalable distribution.

This paper proposes a conceptual framework and supporting architecture for general-purpose process modeling and enactment. The framework includes abstractions of all critical entities and their relationships needed to model complex tasks in a distributed ...

Abstract-The IC* project is an effort to create an environment for the design, specification, and development of complex systems such as communication protocols, parallel machines, and distributed systems. The basis of this work is the IC* model of parallel computation. In this model, a ...

Broadband multimedia applications over enterprise networks requires appropriate communication protocols and enhanced networking infrastructure to provide sufficient quality of service. Our paper presents an architecture of a communication system for manufacturing multimedia applications. The architecture guarantees quality of service for real-time multimedia applications by simplifying the upper networks layers. It is based on an ATM network interface board and a MMS multimedia application service element which is a multimedia extension of MMS standard

The need of communication protocols in todaypsilas environment increases as much as the network explores. Many new kinds of protocols, e.g. for information sharing, security, etc., are being developed day-to-day which often leads to rapid, premature developments. Many protocols have not scaled to satisfy important properties like deadlock and livelock freedom, since MDA focuses on the rapid development rather than on the quality of the developed models. In order to fix the above, we introduce a 2-Phase strategy based on the UML state machine and sequence diagram to satisfy the properties of communication protocols. We convert these models into PROMELA code for execution on the SPIN model checker. The results are compared with the developed UML models.