HLA streaming and real-time extensions.

Abstract

The High Level Architecture (HLA) is IEEE's 1516 standard [1] which defines a software architecture for the development and execution of Distributed Interactive Simulation (DIS). It also provides a general-purpose network communication mechanism for DIS through its implementation---Run-Time Infrastructure (RTI). However, HLA does not address two critical features: stream (audio/video) and real-time transmission. This thesis focuses on solving these two issues. The first part of this thesis reviews the basic concepts of DIS and its evolving history. Then it illustrates how the HLA supports the requirements of the DIS via its service groups, using a virtual shopping mall application as an example. The second part introduces an HLA-compliant solution for stream transmission and control. An audio playback application is illustrated to show how to transfer stream data, using HLA defined APIs and control transfer schedule, using the operating system interval timer. Then, a presentational audio-video continuous-media retrieval application is illustrated to show how to control stream retrieval In the third part, a real-time extension proposal to HLA and an architecture of real-time RTI is presented. The Internet is moving to Quality of Service (QoS) age, which will provide delay and jitter bounded services. With the IP QoS and real-time operating systems involved, it is shown that HLA can support real-time DIS by taking advantages of these new technologies. After analyzing the limitation of current HLA and RTI, a proposal of real-time extension to HLA and the architecture of real-time RTI is illustrated. In the fourth part, our experiences of building QoS networks and a performance analysis, including end-to-end RSVP for unicast and multicast, end-to-end DiffServ, RSVP over differentiated service network, etc., are presented. We hope that the thesis' contributions would create a discussion in the DIS community on the topic of Real-Time DIS (RT-DIS). With new real-time technologies in operating systems and networks blooming, RT-DIS has the possibility of coming true, while its final realization depends on the effort of the whole DIS community.