Consistency Maintenance for Multiplayer Video Games

Abstract

Multiplayer games have to support activities which have differing usability requirements. The usability of the system is directly influenced by the choice of consistency maintenance algorithm. These algorithms must accommodate usability requirements while ensuring shared data is accurately replicated. We demonstrate that consistency maintenance in games can be organized around the AMP properties which state that separate nodes can maintain their instances of shared data using different algorithms (asymmetry), multiple consistency maintenance algorithms can be used within an application (multiplicity), and that consistency maintenance algorithms should be created as modular components (plug-replaceability). The motivation for AMP is outlined with a review of examples from commercial 3D games and related research. Consistency maintenance algorithms are shown to exist in a usability trade-off space. A set of usability metrics is introduced and used to experimentally explore this space. Our results imply that no single algorithm is suitable for every in-game situation. The thesis concludes with an informal evaluation of the AMP based on our experience using the Fiaa.NET as an AMP framework. We found that AMP had several weaknesses, but that these were outweighed by the benefits for the developer.