Design Issues for Peer-to-Peer Massively Multiplayer Online Games.

Massively Multiplayer Online Games (MMOGs) are increasing in both popularity and scale, and while classical Client/Server (C/S) architectures convey some benefits, they suffer from significant technical and commercial drawbacks. This realisation has sparked intensive research interest in adapting MMOGs to Peer-to-Peer (P2P) architectures. This paper articulates a comprehensive set of six design issues to be addressed by P2P MMOGs, namely Interest Management (IM), game event dissemination, Non-Player Character (NPC) host allocation, game state persistency, cheating mitigation and incentive mechanisms. Design alternatives for each issue are systematically compared, and their interrelationships discussed. We further evaluate how well representative P2P MMOG architectures fulfil the design criteria

Update propagation for peer-to-peer-based massively multi-user virtual environments

Over the last decade Massively Multi-user Virtual Environments (MMVEs) have become an integral part of modern culture and business. Applications for these large-scale virtual environments range from gaming to business and scientific research. Some MMVEs reach a user base in the tens of millions and the total number of users is estimated in the billions. Despite this success, launching an MMVEs is still a risky proposition. This is in large part due to the high cost associated with setting up and maintaining the necessary server infrastructure. One way of reducing the costs of operating MMVEs is to switch their system architecture from the current client/server-based model to one based on peer-to-peer (P2P) technologies. This has the potential to significantly reduce the infrastructure costs of MMVEs, as users bring their own resources into the P2P system and servers are no longer required, thus decreasing expenses and market entry barriers. This thesis describes a scalable and low-latency update propagation system for P2P-based MMVEs. Update propagation refers to the exchange of information about changes in the virtual environment between users and is one of the key components of MMVEs. Thus, the described system represents a key step towards operating MMVEs as fully distributed peer-to-peer systems

Solving key design issues for massively multiplayer online games on peer-to-peer architectures

Massively Multiplayer Online Games (MMOGs) are increasing in both popularity and scale on the Internet and are predominantly implemented by Client/Server architectures. While such a classical approach to distributed system design offers many benefits, it suffers from significant technical and commercial drawbacks, primarily reliability and scalability costs. This realisation has sparked recent research interest in adapting MMOGs to Peer-to-Peer (P2P) architectures. This thesis identifies six key design issues to be addressed by P2P MMOGs, namely interest management, event dissemination, task sharing, state persistency, cheating mitigation, and incentive mechanisms. Design alternatives for each issue are systematically compared, and their interrelationships discussed. How well representative P2P MMOG architectures fulfil the design criteria is also evaluated. It is argued that although P2P MMOG architectures are developing rapidly, their support for task sharing and incentive mechanisms still need to be improved. The design of a novel framework for P2P MMOGs, Mediator, is presented. It employs a self-organising super-peer network over a P2P overlay infrastructure, and addresses the six design issues in an integrated system. The Mediator framework is extensible, as it supports flexible policy plug-ins and can accommodate the introduction of new superpeer roles. Key components of this framework have been implemented and evaluated with a simulated P2P MMOG. As the Mediator framework relies on super-peers for computational and administrative tasks, membership management is crucial, e.g. to allow the system to recover from super-peer failures. A new technology for this, namely Membership-Aware Multicast with Bushiness Optimisation (MAMBO), has been designed, implemented and evaluated. It reuses the communication structure of a tree-based application-level multicast to track group membership efficiently. Evaluation of a demonstration application shows i that MAMBO is able to quickly detect and handle peers joining and leaving. Compared to a conventional supervision architecture, MAMBO is more scalable, and yet incurs less communication overheads. Besides MMOGs, MAMBO is suitable for other P2P applications, such as collaborative computing and multimedia streaming. This thesis also presents the design, implementation and evaluation of a novel task mapping infrastructure for heterogeneous P2P environments, Deadline-Driven Auctions (DDA). DDA is primarily designed to support NPC host allocation in P2P MMOGs, and specifically in the Mediator framework. However, it can also support the sharing of computational and interactive tasks with various deadlines in general P2P applications. Experimental and analytical results demonstrate that DDA efficiently allocates computing resources for large numbers of real-time NPC tasks in a simulated P2P MMOG with approximately 1000 players. Furthermore, DDA supports gaming interactivity by keeping the communication latency among NPC hosts and ordinary players low. It also supports flexible matchmaking policies, and can motivate application participants to contribute resources to the system

The use of massively multiplayer online games to augment early-stage design process in construction

Traditional 2-D contour models, Physical Models, Computer-Aided Architectural Design (CAD), Virtual Reality models, Google SketchUp, and Building Information Modelling (BIM) have all greatly enhanced the design process by enabling designers to visualise buildings and the space within them prior to their construction. A recent development is Massively Multiplayer Online Games (MMOG) such as Second Life (SL). These offer users the opportunity to interact with other participants in real time, and so offer an excellent opportunity to experience the environment, layout and form of virtual buildings. However, the effectiveness of such applications to some extent depends upon how realistic the interactions of those using virtual spaces are in relation to interactions within the real world. This research examines the potential of this technology for enhancing and informing the early stage building design process. Initially, the tools currently used by architects at early stages of the RIBA Plan of Work were evaluated through interviewing architects. Then, the advantages of using MMOG over current tools at early-stage design were evaluated through interviews in SL. A virtual model was developed to examine how realistic the visualisation and interaction between end-users in an MMOG was. This was used to propose and validate guidance to incorporating MMOG into the early stages of the RIBA Plan of Work. It revealed that the virtual model created, the validated guidance and a successful example combining 2D sketches, Google SketchUp and MMOG at early-stage design can be used to guide architects to manage the complex decision making process in a simple, easy, cost-effective way, while effectively engaging both professional and non-professional stakeholders