Frank Glinka

High-level development of multiserver online games

Multiplayer online games with support for high user numbers must provide mechanisms to support an increasing amount of players by using additional resources. This paper provides a comprehensive analysis of the practically proven multiserver distribution mechanisms, zoning, instancing, and replication, and the tasks for the game developer implied by them. We propose a novel, high-level development approach which integrates the three distribution mechanisms seamlessly in todays online games. As a possible base for this high-level approach, we describe the real-time framework (RTF) middleware system which liberates the developer from low-level tasks and allows him to stay at high level of design abstraction. We explain how RTF supports the implementation of single-server online games and how RTF allows to incorporate the three multiserver distribution mechanisms during the development process. Finally, we describe briefly how RTF provides manageability and maintenance functionality for online games in a grid context with dynamic resource allocation scenarios.

RTF: a real-time framework for developing scalable multiplayer online games

This paper presents a middleware system called RTF (Real-Time Framework) which aims at supporting the development of modern real-time online games. The RTF automatically distributes the game state among participating servers, and supports parallel state update computations, as well as efficient communication and synchronization between game servers and clients. The game developers access the RTF via a comfortable interface that offers a considerably higher level of abstraction than the time-consuming and error-prone programming in C++ with socket-based communication. We describe the structure of the RTF system and its current proof-of-concept implementation which supports the multi-server parallelization concepts of zoning, instancing and replication for real-time online games. The novel feature of the RTF is the combination of these three concepts which allows the developer to create large, seamless virtual worlds and to migrate zones between servers.

From a single- to multi-server online game: a Quake 3 case study using RTF

Fast-paced action online games like First Person Shooters (FPS) pose high demands on resources and thus require multi-server architectures in order to scale to higher player numbers. However, their multi-server implementation is a challenging task: the game processing needs to be parallelized and the synchronization of the distributed game state needs to be efficiently implemented. As part of the European edutain@grid project 1, we are developing Real-Time Framework (RTF) -- a middleware that provides high-level support for the development of multi-server online games. This paper describes a case study on porting the open-source, single-server Quake 3 Arena game engine to a multi-server architecture using RTF and its state replication approach. We conducted extensive scalability and responsiveness experiments with the ported version of Quake 3 to evaluate the performance of our middleware. The experiments show that the responsiveness of RTF implementation can compete with the original Quake engine, and that the replication support allows to efficiently scale FPS games using multi-server processing.

Improving QoS in real-time internet applications: from best-effort to Software-Defined Networks

Real-Time Online Interactive Applications (ROIA), e.g., multiplayer online games and simulation-based e-learning, are emerging internet applications that make high Quality of Service (QoS) demands on the underlying network. These demands depend on the number of users and the actual application state and, therefore, vary at runtime. Traditional networks have very limited possibilities of influencing the network behaviour to meet the dynamic QoS demands, such that most ROIA use the underlying network on a best-effort basis. The emerging architecture of Software-Defined Networking (SDN) decouples the control and forwarding logic from the network infrastructure, making the network behaviour programmable for applications. This paper analyses ROIA requirements on the underlying network and describes the specification of an SDN Northbound API that allows ROIA applications to specify their dynamic network requirements and to meet them using SDN networks.

Bringing mobile online games to clouds

Massively Multi-player Online Games (MMOG) are characterized by intensive interactions between many simultaneous users and real-time demands on Quality of Service (QoS). Other examples of similar, real-time online interactive applications include various virtual environments, as well as multi-pupil e-learning and simulation-based training courses. A highly desirable enhancement for MMOG is the use of mobile devices for accessing the game application. However, the limited computing power of mobile devices is an obstacle for implementing computation-intensive parts of MMOG, in particular graphics processing, on mobile devices. This paper proposes a novel runtime system for mobile MMOG and other similar applications that moves computation-intensive tasks, including graphics processing, from the mobile devices to Cloud resources. We report experimental results of our runtime system using a realistic multi-player online game.

A dynamic resource management system for real-time online applications on clouds

We consider a challenging class of highly interactive virtual environments, also known as Real-Time Online Interactive Applications (ROIA). Popular examples of ROIA include multi-player online computer games, e-learning and training applications based on real-time simulations, etc. ROIA combine high demands on the scalability and real-time user interactivity with the problem of efficient and economic utilization of resources, which is difficult to achieve due to the changing number of users. We address these challenges by developing the dynamic resource management system RTF-RMS which implements load balancing for ROIA on Clouds. We illustrate how RTF-RMS chooses between three different load-balancing actions and implements Cloud resource allocation. We report experimental results on the load balancing of a multi-player online game in a Cloud environment using RTF-RMS.

A service-oriented interface for highly interactive distributed applications

The emerging class of Real-time Online Interactive Applications (ROIA) include massively-multiplayer online games and e-learning applications. They pose completely new challenges for application developers, including very high level of user interactivity with real-time QoS requirements on distributed performance and scalability. We describe a service-oriented interface that comprises: (1) the Real-Time Framework (RTF) supports a high-level application development process which frees the software developer from the low-level details of distributed computation and communication; (2) the Hoster Management Interface (HMI) supports the transparent resource management for a running application, in particular the creation, controlling and monitoring of ROIA instances. We present our efficient implementation of the interface and describe its use for two particular distributed application scenarios.

Enhancing Grids for Massively Multiplayer Online Computer Games

Massively multiplayer online games (MMOG) are an innovative and challenging class of applications for Grid computing that require large amounts of computational resources for providing a responsive and scalable gameplay for concurrently participating players connected via Internet. We present our Real-Time Framework (RTF)--- a Grid-based middleware for scaling game sessions through a variety of parallelization and distribution techniques. RTF is described within a novel multi-layer service-oriented architecture that comprises three advanced services --- monitoring, capacity planning, and runtime steering --- that use the potential of Grid computing to provide pervasive access to a potentially unbounded number of resources. We report experimental results on the quality of our capacity planning and scalability of the RTF distribution mechanism.

Using Mobile Cloud Computing for Real-Time Online Applications

We consider a challenging class of highly interactive virtual environments, also known as Real-Time Online Interactive Applications (ROIA). Popular examples of ROIA include multi-player online computer games, e-learning and training applications based on real-time simulations, among others. An emerging enhancement for ROIA is the use of mobile devices for accessing the application (mobile ROIA). However, the limited computing power of mobile devices is an obstacle for implementing computation-intensive parts of ROIA, in particular graphics processing, on mobile devices. This paper proposes a runtime system for mobile ROIA that moves computation-intensive tasks, including graphics processing, from the mobile devices to Cloud resources. We report experimental results of our runtime system using a multi-player online game with real-world characteristics.

Towards bringing real-time online applications on Clouds

The paper studies an emerging class of Real-Time Online Interactive Applications (ROIA), including multi-player online computer games, e-learning and training applications based on real-time simulations, etc. ROIA combine the challenge of the scalability and real-time user interactivity with the problem of efficient and economic utilization of resources for changing number of users. To address these challenges, we develop a dynamic resource management system which implements load balancing for ROIA on Clouds. We illustrate three different load-balancing actions and report experimental results on bringing a multi-player online game on Cloud.