This report describes an ATM multipoint connection caching strategy (AMCC) to control the explosive growth of traffic within the network and at an endpoint in a large distributed interactive simulation (DIS) application such as a battlefield simulation. For very large DIS applications with 100000 entities, the current method of broadcasting information among entities will no longer be feasible due to the computational and network bandwidth limitations. Our scheme divides the simulation space into grids and each grid square or a set of grid squares forms a multicast group. Entities join the groups within their perception range and thus, they receive state updates only from entities within their perception range. The AMCC utilizes the unique capabilities of our dynamic multipoint ATM signaling protocol, CMAP. We have implemented the AMCC and have successfully demonstrated a small DIS battlefield simulation application running over our ATM testbed.

When creating mission-critical distributed systems using off-the-shelf components, it is important to assess the dependability of not only the hardware, but the software as well. This paper proposes a way to test operating system dependability. The concept of response regions is presented as a way to visualize erroneous system behavior and gain insight into failure mechanisms. A 5-point "CRASH" (catastrophic, restart, abort, silent, hindering) scale is defined for grading the severity of robustness vulnerabilities encountered. Test results from five operating systems are analyzed for robustness vulnerabilities, and exhibit a range of dependability. Robustness benchmarking comparisons of this type may provide important information to both users and designers of off-the-shelf software for dependable systems.