An approach to achieve scalability through a structured peer-to-peer network for massively multiplayer online role playing games

Scalability is a critical issue for Massively Multiplayer Online Role Playing Games (MMORPG). To address the scalability drawbacks of current central server model, we present a scenario to support MMORPG through Pastry, a structured peer-to-peer overlay. In order to closely reflect an advanced MMORPG configuration, the scenario considers bandwidth and latency constraints required by the games based on actual MMORPG traffic pattern. A simulation model is developed to evaluate the performance of Pastry in supporting such a scenario. Results show that Pastry performs well in distributing node stress. However, there is a bottleneck in terms of upstream bandwidth usage, which can be removed by low-cost algorithms. Results also show that using Scribe multicast tree built on top of Pastry to disseminate game traffic is an effective way to save bandwidth usage. In addition, Scribe multicast tree scales well in supporting the scenario with respect to the tree length. When a tree size increases five times, the length of the tree only increases less than two levels.