OMG Data Distribution Service Research Articles

DDS : A Solution to Network Centric Warfare

The Open Management Group Data Distribution Service ( OMG DDS ) is a standard for publish-subscribe data distribution systems which is emerging as a specification for data exchange. It is a type of Message Oriented Middleware ( MOM ) that provides various functionalities such as portability and interoperability across many DDS implementations. In this, we create models which are platform independent. One platform can be mapped to others. These platforms can be in different programming languages. The existing issues with this technology include its inability to support request-reply services, file transfer and transaction processing. These issues can be considered as research work for future. Nowadays, there is always a need to exchange data among several communication machines instead of just a single machine. DDS caters this need by allowing data to be sent and received in a distributed environment. While doing so, the various security issues related to data integrity and loss of data are also taken into consideration. In this paper, Data Distribution Service ( DDS ) has been implemented to be used in network centric warfare, in three programming languages i.e Java, C and C++ in order to allow for cross language communication without any loss of data on a standalone mode .Data can also be exchanged between several machines in a distributed environment.

국방 훈련체계용 가상물리시스템 시간 동기화 기법

LVC(Live Virtual Constructive) 통합 훈련 체계는 대표적인 가상물리시스템 중 하나이다. LVC 훈련 체계를 구성하는 각 L,V,C 체계들은 서로 다른 시간 도메인, 해상도 및 동작 방식을 갖는다. 이에 각 체계의 이종 미들웨어들을 공통의 통신 미들웨어로서 통합하고, 연동 gateway (GW)를 이용하여 이종 체계를 연동하는 방안 연구는 매우 중요하다. 특히, LVC체계는 서로 다른 시간 도메인을 사용하고 있기 때문에 다른 체계 간 이벤트들의 인과성 보장과 시간 동기화에 대한 연구가 필요하다. 본 연구에서는 LVC 훈련체계의 통합 미들웨어로서 L 체계의 실시간 통신 미들웨어인 OMG DDS(Data Distribution Service)를 기반으로 HLA(High Level Architecture)/RTI(Run Time Infrastructure)기반의 시뮬레이션 시간을 사용하는 V, C 체계와 시간 차원에서 연동하는 방안을 제시한다. 본 논문에서는 HLA의 Time management 기능과 Clock Federate를 기반으로 DDS와 HLA 각각의 통신 개체인 파티서펀트(Participant)와 페더레이트(Federate)간 인과성을 유지하는 정밀한 시간 동기화 기법을 제안한다. 더불어, 각 미들웨어 상에서 실제 응용을 개발하여 제안한 방식에 의해 이종 체계 간 시간 제어 및 동기화가 이루어짐을 검증한다. LVC(live-virtual-constructive) integrated training system is a representative cyber-physical system. Each systems in a LVC system has different time domain, resolution and operation methods. So, it is very important to integrate different middlewares as a common middleware for heterogeneous systems using inter-working GWs. Especially, since the LVC system uses different time, it is necessary to study the method for guaranteeing causality and time synchronization among the events from different systems. In this study, we propose an time synchronization scheme to integrate the virtual and constructive system which use the simulation time of HLA (High Level Architecture)/ RTI (Run Time Infrastructure) into the live system based on the OMG DDS (Data Distribution Service). We propose a precise time synchronization scheme based on HLA time management and clock federate between participants and federates which are the communication objects of DDS and HLA/RTI respectively. In addition, we verified that time is well-synchronized among heterogeneous systems using the suggested scheme by implementing and demonstrating simulation applications on each middleware.

Dealing Handover with Publish/Subscribe Middleware for Vehicular Networks: Modeling and Performance Analysis

Because of the high mobility of nodes and of the low node density, the vehicular networks is sparse, partitioned into several areas, and thus characterized by an intermittent connectivity. So, in such networks, the mobility management, providing an effective handover and the delivery of the messages with low loss, is a real challenge. The content based publish/subscribe middleware has proven its efficiency for messages delivery in networks with fixed clients. However, by its decoupling in space, time and flow content based, publish/subscribe becomes a good solution for mobile wireless environments which are characterized by frequent and unpredictable disconnections due to clients mobility or weak wireless channel. Yet, in such environments it is essential that, when clients disconnect from an attachment point and reconnect to another, they can receive the messages that were published after they disconnected. This paper propose a content-based publish/subscribe middleware as data dissemination and disconnections management solution, based on the OMG's Data Distribution Service (DDS), which performs effective handover and reroutes undelivered events with low loss rate. For performance evaluation, the paper proposal implements a content based publish/subscribe middleware prototype first to analyze the system and then to demonstrate, through these evaluations, that the publication/subscription system allows to adapt itself quickly to the frequent disconnections. Then it will be demonstrated that the handover management protocol can improve effectively the performances of the system.

Design and Evaluation of an Autonomous Load Balancing System for Mobile Data Stream Processing Based On a Data Centric Publish Subscribe Approach

Several new applications of mobile computing environments, such as Intelligent Transportation Systems, Fleet Management and Logistics, and integrated Industrial Process Automation share the requirement of remote monitoring and high performance processing of huge data streams produced by large sets of mobile nodes. Two key requirements for the deployment and operation of such mobile infrastructures are the handling of large and variable numbers of wireless connections to the monitored mobile nodes regardless of their current use or locations, and to automatically adapt to variations in the volume of the mobile data streams. This article describes the design, implementation, and evaluation of an autonomic mechanism for load balancing of mobile data streams. The autonomic capability has been incorporated into a scalable middleware system based on a Data Centric Publish Subscribe approach using the OMG Data Distribution Service (DDS) standard and aimed at real-time and adaptive handling of mobile connectivity and data stream processing for great sets of mobile nodes. A significant amount of evaluation experiments of the proposed infrastructure is presented, reinforcing its viability and the benefits arising from the use of an autonomic approach to handle the requirements of high variability and scalability.

Supporting SIP-based end-to-end Data Distribution Service QoS in WANs

Assuring end-to-end QoS in enterprise distributed real-time and embedded (DRE) systems is hard due to the heterogeneity and transient behavior of communication networks, the lack of integrated mechanisms that schedule communication and computing resources holistically, and the scalability limits of IP multicast in wide-area networks (WANs). This paper makes three contributions to research on overcoming these problems in the context of enterprise DRE systems that use the OMG Data Distribution Service (DDS) quality-of-service (QoS)-enabled publish/subscribe (pub/sub) middleware over WANs. First, it codifies the limitations of conventional DDS implementations deployed over WANs. Second, it describes a middleware component called Proxy DDS that bridges multiple, isolated DDS domains deployed over WANs. Third, it describes the NetQSIP framework that combines multi-layer, standards-based technologies including the OMG-DDS, Session Initiation Protocol (SIP), and IP DiffServ to support end-to-end QoS in a WAN and shield pub/sub applications from tedious and error-prone details of network QoS mechanisms. The results of experiments using Proxy DDS and NetQSIP show how combining DDS with SIP in DiffServ networks significantly improves dynamic resource reservation in WANs and provides effective end-to-end QoS management.

Model-driven generative framework for automated OMG DDS performance testing in the cloud

The Object Management Group's (OMG) Data Distribution Service (DDS) provides many configurable policies which determine end-to-end quality of service (QoS) of applications. It is challenging to predict the system's performance in terms of latencies, throughput, and resource usage because diverse combinations of QoS configurations influence QoS of applications in different ways. To overcome this problem, design-time formal methods have been applied with mixed success, but lack of sufficient accuracy in prediction, tool support, and understanding of formalism has prevented wider adoption of the formal techniques. A promising approach to address this challenge is to emulate system behavior and gather data on the QoS parameters of interest by experimentation. To realize this approach, which is preferred over formal methods due to their limitations in accurately predicting QoS, we have developed a model-based automatic performance testing framework with generative capabilities to reduce manual efforts in generating a large number of relevant QoS configurations that can be deployed and tested on a cloud platform. This paper describes our initial efforts in developing and using this technology.

Supporting end-to-end quality of service properties in OMG data distribution service publish/subscribe middleware over wide area networks

Assuring end-to-end quality-of-service (QoS) in distributed real-time and embedded (DRE) systems is hard due to the heterogeneity and scale of communication networks, transient behavior, and the lack of mechanisms that holistically schedule different resources end-to-end. This paper makes two contributions to research focusing on overcoming these problems in the context of wide area network (WAN)-based DRE applications that use the OMG Data Distribution Service (DDS) QoS-enabled publish/subscribe middleware. First, it provides an analytical approach to bound the delays incurred along the critical path in a typical DDS-based publish/subscribe stream, which helps ensure predictable end-to-end delays. Second, it presents the design and evaluation of a policy-driven framework called Velox. Velox combines multi-layer, standards-based technologies—including the OMG DDS and IP DiffServ—to support end-to-end QoS in heterogeneous networks and shield applications from the details of network QoS mechanisms by specifying per-flow QoS requirements. The results of empirical tests conducted using Velox show how combining DDS with DiffServ enhances the schedulability and predictability of DRE applications, improves data delivery over heterogeneous IP networks, and provides network-level differentiated performance.

A content-aware bridging service for publish/subscribe environments

The OMG DDS (Data Distribution Service) standard specifies a middleware for distributing real-time data using a publish-subscribe data-centric approach. Until now, DDS systems have been restricted to a single and isolated DDS domain, normally deployed within a single multicast-enabled LAN. As systems grow larger, the need to interconnect different DDS domains arises. In this paper, we consider the problem of communicating disjoint data-spaces that may use different schemas to refer to similar information. In this regard, we propose a DDS interconnection service capable of bridging DDS domains as well as adapting between different data schemas. A key benefit of our approach is that is compliant with the latest OMG specifications, thus the proposed service does not require any modifications to DDS applications. The paper identifies the requirements for DDS data-spaces interconnection, presents an architecture that responds to those requirements, and concludes with experimental results gathered on our prototype implementation. We show that the impact of the service on the communications performance is well within the acceptable limits for most real-world uses of DDS (latency overhead is of the order of hundreds of microseconds). Reported results also indicate that our service interconnects remote data-spaces efficiently and reduces the network traffic almost N times, with N being the number of final data subscribers.

Infrastructure for component-based DDS application development

Enterprise distributed real-time and embedded (DRE) systems are increasingly being developed with the use of component-based software techniques. Unfortunately, commonly used component middleware platforms provide limited support for event-based publish/subscribe (pub/sub) mechanisms that meet both quality-of-service (QoS) and configurability requirements of DRE systems. On the other hand, although pub/sub technologies, such as OMG Data Distribution Service (DDS), support a wide range of QoS settings, the level of abstraction they provide make it hard to configure them due to the significant source-level configuration that must be hard-coded at compile time or tailored at run-time using proprietary, ad hoc configuration logic. Moreover, developers of applications using native pub/sub technologies must write large amounts of boilerplate "glue" code to support run-time configuration of QoS properties, which is tedious and error-prone. This paper describes a novel, generative approach that combines the strengths of QoS-enabled pub/sub middleware with component-based middleware technologies. In particular, this paper describes the design and implementation of DDS4CIAO which addresses a number of inherent and accidental complexities in the DDS4CCM standard. DDS4CIAO simplifies the development, deployment, and configuration of component-based DRE systems that leverage DDS's powerful QoS capabilities by provisioning DDS QoS policy settings and simplifying the development of DDS applications.

Embedding Authentication & Authorization in Discovery Protocols for Standard Based Publish/Subscribe Middleware: A Performance Evaluation

Standard based Pub/Sub middleware, such as OMG Data Distribution Service (DDS), could assume a key role in supporting computer communications requiring continuous state information updating, deterministic deadline to data delivering and real time information adjourning. This kind of capability could be well ex-ploited by Peer-To-Peer (P2P) systems, Internet-wide as long as private ones, like in Public Safety or Civil Protection Communication Systems; but Pub/Sub specifications, and DDS/RTPS (Real Time Publish Sub-scribe) as well, usually do not provide Authentication & Authorization (AA) mechanisms. In the present work two important novelties are assessed: a possible scheme to implement AA in DDS/RTPS networks and a time performance evaluation study about embedded Authentication in RTPS.