Multiplayer Networked Gaming with the Session Initiation Protocol

With a strong push from commercial ventures like Microsoft Xbox and Sony Playstation , the multiplayer networked gaming industry continues to grow steadily. Multiplayer games allow geographically dispersed players to participate in a single game and in order to provide interaction amongst players in such environments, text messaging and real-time voice through VoIP is used. However, such interactions are out-of-band (not based on game contexts), userinitiated and severely limited in operability and functionality. In this paper, we present mechanisms and design of a prototype that uses the lightweight Session Initiation Protocol (SIP) to provide context-aware gaming. In addition to allowing players to talk to each other to coordinate teammates and activities (through a static team-based audio conference) as in current systems, it supports real-time communication among players based on shared contexts like the same physical location or room within the gaming environment. This is provided through seamless management of audio sessions (conferences) based on player movements/behaviors which change the shared game context. We extend our earlier work by providing a dynamic form of shared context, using a modified SIP session negotiation mechanism. In addition, through the use of SIP as the game communication protocol, we propose to make VoIP a first class member of the game state. This allows a unified architecture for context-aware communication and gaming. We also present a sophisticated gaming scenario, in which VoIP is used to relay information about another player s distance and location with respect to the recipient, e.g. players farther away sound farther away. 2005 Elsevier B.V. All rights reserved.