Jukka-Pekka Laulajainen

Platform for distributed 3D gaming

Video games are typically executed on Windows platforms with DirectX API and require high performance CPUs and graphics hardware. For pervasive gaming in various environments like at home, hotels, or internet cafes, it is beneficial to run games also on mobile devices and modest performance CE devices avoiding the necessity of placing a noisy workstation in the living room or costly computers/consoles in each room of a hotel. This paper presents a new cross-platform approach for distributed 3D gaming in wired/wireless local networks. We introduce the novel system architecture and protocols used to transfer the game graphics data across the network to end devices. Simultaneous execution of video games on a central server and a novel streaming approach of the 3D graphics output to multiple end devices enable the access of games on low cost set top boxes and handheld devices that natively lack the power of executing a game with high-quality graphical output.

An Empirical Study of NetEm Network Emulation Functionalities

In this paper we have evaluated the main functionalities of NetEm, a popular Linux based network emulator, which we have used to stress test the performance of the Games@Large distributed gaming system. We have performed a number of tests on different NetEm functionalities in order to evaluate their practical performance conformity and validity versus the NetEm description and theoretical expectations. We have found that the NetEm behaviour conforms to expectations for the emulation of delay and packet loss without correlation. However, in the case of jitter emulation, the actual realized jitter is lower than the given input value. It is an important fact to be aware of when using NetEm for different application testing. This paper also provides a baseline methodology for network emulation tool validation.

Experiments with QoS-Aware Gaming-on-Demand Service

This paper presents experiments with an adaptation architecture for a novel client-server based broadband gaming solution, a gaming-on-demand service. The adaptation solution was implemented to an experimental gaming-on-demand setup to evaluate its advantages by measuring adaptation performance under emulated real world network conditions. The obtained results show that the gaming-on-demand service performance is improved significantly when the adaptation solution is used

QoS-Aware real-time video encoding How to Improve the User Experience of a Gaming-on-Demand Service

The advances in multimedia and network technologies have created novel services (e.g. Video-on-Demand, IPTV and Gaming-on-Demand), which set high Quality of Service (QoS) requirements. There are various existing QoS support technologies for networks, but these are used and controlled by network operators and single service providers have no possibility to control the whole end-to-end path from their server to the user. Instead the service providers can use various application level solutions to improve the user-perceived quality of video services. One possibility is to monitor the network status end-to-end and change the video encoding parameters accordingly. This paper considers dynamic video encoding adaptation focusing to improve the user-perceived service quality of a Gaming-on-Demand service, which is a highly demanding interactive multimedia application based on a client-server infrastructure and video streaming.

Two-phased network traffic classification method for quality of service management

Identification of network traffic is crucial in network management and monitoring purposes. Nowadays port based and payload based classification methods have become inadequate as many applications use dynamically allocated port numbers, masquerade to be another application by using some standard port number or use encryption to avoid detection. Recent studies propose an alternative technique for network traffic classification utilizing statistical characteristics of network flows in classification. Most of these studies focus on classifying flows when flows have finished. This kind of classification is not sufficient for quality of service management purposes, therefore network flows have to be classified as early as possible. This paper introduces a two-phased classification method which is capable of classifying network flows early in the connection and providing a secondary classification phase to improve the classification accuracy. A simple K-Means clustering technique is utilized in both classification phases. The classifier was trained and evaluated using manually generated training and evaluation datasets. According to the results two-phased classifier classified 97.8 % of target applications correctly and was able to detect untrained application flows at high precision. Also individual classification phases produced high overall accuracies and precise detections of unknown traffic.

Testing Cross-Platform Streaming of Video Games over Wired and Wireless LANs

In this paper we present a new cross-platform approach for video game delivery in wired and wireless local networks. The developed 3D streaming and video streaming approaches enable users to access video games on set top boxes and handheld devices that natively are not capable to run PC games. During the development of the distributed gaming system we have faced a number of challenges and problems posed by the hardware and network limitations. In order to solve these problems we have developed a multilevel testing methodology which is based on user assessment and technical measures for the system under development. In this paper we focus on the technical measures and instrumentation that we use for the system’s performance measurement and testing. The benefits of our testing methodology are demonstrated through examples from the development and testing work.

Empirical Evaluation of Streamed Online Gaming over WiMAX

Online gaming is one of the main Internet services holding potential for a significant growth. Currently, much attention is paid on studying how high-quality 3D games with varying resource demands can be played over the Internet streamed real-time from a remote game server. This enables end-users to play high-quality games without need for having very powerful game machines as most of the processing is performed already in the game server. This type of gaming is sensitive to network conditions, especially, to end-to-end delays of both uplink and downlink. In this study, we evaluate the quality of streamed online gaming over fixed WiMAX through empirical evidence. We evaluate the gaming quality with various background traffic loads and types in scenarios where a WiMAX link is employed as a backhaul connection. In addition, we assess the importance of various WiMAX QoS scheduling schemes to keep the gaming experience high despite the congestion in the serving base station. We find that the quality of streamed gaming is very sensitive to delays and already the characteristic transmission latencies of WiMAX are near the edge of a smooth gaming experience. With heavy traffic loads, inflicting high delays, the gaming experience faces a radical degradation, which can be clearly mitigated by using scheduling schemes privileging the game traffic.

Automatic QoS control in UPnP home networks

UPnP Forum specifies a framework for Quality of Service (QoS) in its UPnP QoS architecture. The framework enables automatic configuration of priority based QoS to network devices according to local policies. The downside of the framework is that it relies on a control point, which acts as an initiator for UPnP QoS operations. In practice, this means that each application should explicitly support UPnP QoS to be able to use the services provided by the framework. In this paper, we propose a supplemental component for the architecture which enables the use of UPnP QoS without any support from the applications using the network. The network traffic is listened by a passive component which uses statistical methods for classifying the network traffic flows and acts as a control point for the UPnP QoS framework. Our results show that even very simple behavior-based methods can be used for traffic classification with a fairly good precision. In our experiment, the automatic UPnP QoS control point was able to perform the classification with an overall accuracy of 92% based only on the packet sizes of the four first packet of each flow. We assume tha the accuracy can be further improved using additional mechanisms after the initial fast classification.

Study of YouTube demand patterns in mixed public and campus WiFi network

In this paper we study traffic patterns in a large municipal WiFi network and in particular those of the most bandwidth hungry application, viz. YouTube, for which we provide a detailed analysis of demand in different geographical areas and over time. We consider the possibilities to reduce network traffic and increase Quality of Experience (QoE) by serving repeated requests for YouTube videos from caches placed either at the network head end, at the wireless access points, or in the user devices. Our data confirms that a significant part of the YouTube traffic can be served by such devices and that there exists a potential to optimize caching performance by exploiting the content demand locality. We also discover a previously unknown pattern of periodicity in content demand and present a simple example of how to exploit this in cache design.

Dynamic Subscription-Based QoS Service for Traffic Optimization

Real-time Internet services such as video transmission and online gaming often require privileged treatment in the Internet routers and wireless links in order to meet their real-time QoS requirements. The challenge is to know which are the services requiring higher priority and when this special treatment is needed. In this study, we introduce mechanisms to intelligently classify different traffic flows and to utilize this information in a dynamic adjustment of traffic priorities. In the presented solution, mobile stations can dynamically subscribe to special treatment for their network services. We capitalize on a deployment of the solution in the context of scalable video and employ fixed WiMAX to provide broadband quality of service enabled wireless connection. Beyond introducing and demonstrating the feasibility of such a deployment, our measurement results attest that dynamic traffic priority change can provide sufficient mechanism to sustain the quality of the real-time service despite the unreliable wireless link.