Uniform and Non-Uniform Zoning for Load Balancing in Virtual Environments

Maintaining a stable system for thousands of users is a difficult task. Massively Multiplayer Online Game (MMOG) dealing thousands of players preserves consistency by sharing relevant game states among the interacting parties. The lag of state sharing becomes excessive when the system is overloaded. Current practices supporting a massive number of users generally divide the game world into zones which are managed by servers. However, such zoning restricts cross-zonal interactions and exposes division of the game space. To address these problems, we present load-balancing algorithms for both uniform and non-uniform zonal Peer-to-Peer (P2P) MMOGs. The proposed load-balancing schemes identify a loaded server in terms of either the number of players or packets processed per unit time, and then move the load to other servers considering communication overhead and P2P overlay restructuring. The non-uniform load balancing, named adaptive scheme, uses a bisection procedure that does not adhere to any predefined zone size - zone sizes are flexible and can be determined dynamically. The outlined Multilevel Multiphase Load Balancing (MMLB) method designed for uniform zones reduces load in a step-by-step manner, and avoids problems associated with current load balancing schemes. Our results show that reducing load at any magnitude not necessarily improves performance. By comparison, MMLB performs better than adaptive scheme especially for a series of hotspots.