ARTICLE IN PRESS J. Parallel Distrib. Comput. ( ) – Contents lists available at ScienceDirect J. Parallel Distrib. Comput. journal homepage: www.elsevier.com/locate/jpdc Synchronization in federation community networks Dan Chen a,c,∗ , Stephen J. Turner b , Wentong Cai b , Georgios K. Theodoropoulos a , Muzhou Xiong b,d , Michael Lees a a School of Computer Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK b School of Computer Engineering, Nanyang Technological University, 639798, Singapore c Institute of Electrical Engineering, Yanshan University, Qinhuangdao, 066004, China d School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China article info Article history: Received 2 September 2008 Received in revised form 17 October 2009 Accepted 20 October 2009 Available online xxxx Keywords: Synchronization Grid computing High level architecture Runtime infrastructure Federation community abstract A large scale High Level Architecture (HLA)-based simulation can be constructed using a network of sim- ulation federations to form a ‘‘federation community’’. This effort is often for the sake of enhancing scal- ability, interoperability, composability and enabling information security. Synchronization mechanisms are essential to coordinate the execution of federates and event transmissions across the boundaries of interlinked federations. We have developed a generic synchronization mechanism for federation commu- nity networks with its correctness mathematically proved. The synchronization mechanism suits various types of federation community network and supports the reusability of legacy federates. It is platform- neutral and independent of federate modeling approaches. The synchronization mechanism has been evaluated in the context of the Grid-enabled federation community approach, which allows simulation users to benefit from both Grid computing technologies and the federation community approach. A se- ries of experiments has been carried out to validate and benchmark the synchronization mechanism. The experimental results indicate that the proposed mechanism provides correct time management services to federation communities. The results also show that the mechanism exhibits encouraging performance in terms of synchronization efficiency and scalability. © 2009 Elsevier Inc. All rights reserved. 1. Introduction Distributed simulation technology facilitates the construction of a large scale simulation with simulation components of vari- ous types, which can be developed independently and distributed geographically. The High Level Architecture (HLA) defines the rules, interface specification and object model template to sup- port reusability and interoperability amongst the simulation com- ponents, known as federates [12]. While the HLA serves as the de facto standard for distributed simulations, the Runtime Infrastruc- ture (RTI) software provides services 1 to support and synchronize the interactions amongst different federates conforming to the HLA standard to sustain an overall simulation application, known as a federation as shown in Fig. 1(A). ∗ Corresponding author at: School of Computer Science, University of Birming- ham, Edgbaston, Birmingham, B15 2TT, UK E-mail addresses: d.chen@cs.bham.ac.uk, chendan@pmail.ntu.edu.sg, danjj43@hotmail.com (D. Chen), assjturner@ntu.edu.sg (S.J. Turner), aswtcai@ntu.edu.sg (W. Cai), gkt@cs.bham.ac.uk (G.K. Theodoropoulos), mzxiong@ntu.edu.sg (M. Xiong), mhlees@ntu.edu.sg (M. Lees). 1 A total of six service categories is defined in the IEEE 1516 HLA standard, namely Federation Management, Declaration Management, Object Management, Ownership Management, Data Distribution Management and Time Management. In the case where the problem domain is particularly complex or involves multiple collaborative parties, the analysts often need to construct large scale HLA-based simulations which may involve a large number of federates and vast computing resources over a network or the Internet. Some typical examples are: military com- mission rehearsal, Internet gaming, biology simulation, and supply chain simulation. Sometimes such large scale simulations need to be constructed upon multiple simulation federations. Despite the tremendous advantages brought by the HLA technologies, the HLA standard does not explicitly sustain interoperation between fed- erates across the boundaries of federations. To address this issue, a method has been proposed to harness a network of federations to achieve a common goal in the form of a ‘‘federation commu- nity’’ [24]. Fig. 1(B) illustrates an example of federation community network. In addition to the advantages of using flat federations, 2 simulation developers and users can benefit from the federation community method in (1) improving the scalability of large and complex applications by reducing the bandwidth requirements through the partitioning of network load and the filtering out of 2 To distinguish a traditional federation from federation communities, a simulation upon an individual federation is called a flat federation. 0743-7315/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jpdc.2009.10.006 Please cite this article in press as: D. Chen, et al., Synchronization in federation community networks, J. Parallel Distrib. Comput. (2009), doi:10.1016/j.jpdc.2009.10.006