Research And Realization Of Application Layer Multicast Communication Technology Based On Distributed Interactive Simulation System

With the increasing development of computer technology, network technology and simulating technology, more and more distributed interactive simulation has been applied within the domain of military simulation. More development has been made in military simulation, more interoperability and reusability are requested. So, U.S. DoD has proposed a new technical framework named HLA (High Level Architecture) for simulation. The goal of HLA is to improve the interoperability and reusability of various simulation system and other components within military simulation domain. At present, the design and development of HLA/RTI simulation system has been the hot spots in simulation domain, especially in military domain.As the backup of HLA/RTI simulation system, the capability of underlying network communication affects the performance of RTI. In early DIS simulation system, broadcasting was adopted to transport packets. With the increase of the nodes in the network, the traffic will increase so greatly in the network that broadcasting storm would be caused. As a result the network will get worse and worse, and halt in the end. Broadcasting is replaced by unicast and multicast in the HLA/RTI simulation system. The data packets were sent to data subscriber from data publisher directly so that the performance of RTI was improved.Much time had been taken to study IP multicasting, it's difficult to apply it to applications because of some problem about software and hardware. Recently, some new thought was put forward by some researcher. The new technology is called Application Layer Multicasting which implement multicastint in end system instead of in network system.This paper begins with the concept of HLA/RTI and the requirement of HLA/RTI simulation system. It also analyzes the shortage of IP multicasting and introduces the Application Level Multicasting. This paper also proposes a solution to HLA/RTI simulation system based on Application Level Multicasting and points a new way to settle the communication problem in HLA/RTI simulation system.