Comparing interest management algorithms for massively multiplayer games

Abstract

Broadcasting all state changes to every player of a massively multiplayer game is not a viable solution. To successfully overcome the challenge of scale, massively multiplayer games have to employ sophisticated interest management techniques that only send relevant state changes to each player. This paper compares the performance of different interest management algorithms based on measurements obtained in a real massively multiplayer game using human and computer-generated player actions. We show that interest management algorithms that take into account obstacles in the world reduce the number of update messages between players by up to a factor of 6, and that some computationally inexpensive tile-based interest management algorithms can approximate ideal visibility-based interest management at very low cost. The experiments also show that measurements obtained with computer-controlled players performing random actions can approximate measurements of games played by real humans, provided that the starting positions of the random players are chosen adequately. As the size of the world and the number of players of massively multiplayer games increases, adaptive interest management techniques such as the ones studied in this paper will become increasingly important.

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

“…Some authors have developed techniques for distributing the game load based on AOI [7,13,28]. However, in an MMORPG, apart from updating their AOI, players also frequently need to update their view of the virtual game world, causing a high communication overhead for such players.…”

Large-scale immersive video conferencing by altering video quality and distribution based on the virtual context

“…Earlier research on multi-user virtual environments focused on a technique, known as Area of Interest (AOI) management, to reduce the amount of state information sent to each client [2]. Typically, the AOI of a client is viewed to be within a certain virtual distance of the current position.…”

Design issues for Peer-to-Peer Massively Multiplayer Online Games

“…This model is also referred to as the 'aura-nimbus' model (Boulanger et al, 2006;Morgan et al, 2005) because of its key abstractions: aura and nimbus. The 'aura' means the area that bounds the presence of an object in space, whereas the 'nimbus' means the mutual awareness levels between two objects.…”

“…The advantage of the spatial model is that it allows fine-grained IM in which only necessary messages are transmitted among relevant peers (Boulanger et al, 2006). However, a significant drawback is that it requires all objects to exchange positional update information to identify when AOI collisions occur.…”

“…Previous work has investigated an individual design issue, e.g., several IM schemes are compared in Boulanger et al (2006) and Morgan et al (2005). Other related work focuses on general requirements of a P2P MMOG, e.g., scalability, availability, interactivity (Schiele et al, 2007;Simon et al, 2007).…”