Distributing game instances in a hybrid client-server/P2P system to support MMORPG playability

Abstract

MMORPG (Massively Multiplayer Online Role Playing Games) is the most popular genre among network gamers, and now attract millions of users, who play simultaneously in an evolving virtual world. This huge number of concurrent players requires the availability of high performance computation servers. Additionally, gaming aware distribution mechanisms are needed to distribute game instances among servers to avoid load imbalances that affect performance negatively. In this work, we tackle the problem of game distribution and scalability by means of a hybrid Client-Server/P2P architecture that can scale dynamically according to the demand. To manage peak loads that occur during the game, we distribute game computation across the system according to the behavior of MMORPGs. We distinguish between the computation associated with the Main Game, that affects all players, and the computation of Auxiliary Games that affects only a few players and acts in isolation from the execution of the Main Game. Taking this distinction into account, we propose a mechanism that is focused in the distribution of Auxiliary Games, as an entity, across the pool of servers and peers of the underlying hybrid architecture. We evaluate the performance of the balancing mechanism taking the criteria of latency and reliability into account, and we compare the effectiveness of the mechanism with a classic approach that applies load balancing to individually players in a Client-Server system. We show that the balancing mechanism based on the latency criteria provides lower latency than the classical proposal, while in relation to reliability, we obtain a failure probability of under 0.9 % in the worst case, which is amply compensated by the scalability provided by the use of the P2P area.