No abstract

No abstract

No abstract

Data Center Networks (DCNs) form the backbone of many Internet applications and services that have become necessary in daily life. Energy consumption causes both economic and environmental issues. It is reported that 10% of global energy consumption is due to ICT and network usage. Computer networking equipment is designed to accommodate network traffic; however, the level of use of the equipment is not necessarily proportional to the power consumed by it. For example, DCNs do not always run at full capacity yet the fact that they are supporting a lighter load is not mirrored by a reduction in energy consumption. DCNs have been shown to unnecessarily over-consume energy when they are not fully loaded. In this paper, we propose a new framework that reduces power consumption in software-defined DCNs. The proposed approach is composed of a new Integer Programming model and a heuristic link utility-based algorithm that strikes a balance between energy consumption and performance. We evaluate the proposed framework using an experimental platform, which consists of an optimization tool called LinGo for solving convex and non-convex optimization problems, the POX controller and the Mininet network emulator. Compared with the state-of-the-art approach, the equal cost multi-path algorithm, the results show that the proposed method reduces the power consumption by up to 10% when the network is experiencing a high traffic load and 63.3% when the traffic load is low. Based on these results, we outline how machine learning approaches could be used to further improve our approach in future work.

No abstract

The class of distributed Real-time O nline Interactive Applications (ROIA) includes such important applications as Massively Multiplayer Online Games (MMOGs), as well as interactive e-Learning a nd simulation systems. These applications usually work in a persistent environment (also called world) which continues to exist and evolve also while the user is offline and away from the application. The challenge is how to efficiently make the world and the player characters persistent in the system over time. In this paper, we deal with storing persistent data of real-time interactive applications in modern relational databases. We analyze the major requirements to a system for persistency and we describe a preliminary design of the Entity Persistence Module (EPM) middleware which liberates the application developer from writing and maintaining complex a nd error-prone code for persistent data management. EPM automatically performs the mapping operations to store/ retrieve the complex data to/from different types of relational databases, supports the management of persistent data in memory, and integrates it into the main loop of the ROIA client-server architecture.

Real-time Online Interactive Applications (ROIA) like multiplayer online games usually work in a persistent environment (also called virtual world) which continues to exist and evolve also while the user is offline and away from the application. This paper deals with storing persistent data of real-time interactive applications in modern relational databases. We describe a preliminary design of the Entity Persistence Module (EPM) middleware which liberates the application developer from writing and maintaining complex and error-prone, application-specific code for persistent data management. I. INTRODUCTIONReal-time Online Interactive Applications (ROIA) can potentially be used simultaneously by thousands of users. The probably most demanding applications of this type are Massively Multiplayer Online Games (MMOGs) which are our specific target in this paper.In a MMOG, players are represented by virtual characters called avatars which communicate and interact with each other in a large virtual world. The changeable world objects are called dynamic objects or entities. In addition to interacting with other players, an important incentive of a player is to develop his avatar by equipping with new objects or learning new skills. To make this development persistent, i.e. such that changes are not lost when the game is interrupted, they must be saved (persisted). To increase the reliability of a game, not only the states of avatars should be stored, but also the global state of the game world is usually stored permanently.In this paper, we present a preliminary design of our persistency system for ROIA -the Entity Persistence Module (EPM) -which we design as a middleware that connects the application with different types of relational databases. We describe how EPM provides the application developer with a programming interface (API) in order to simplify the use of the presented persistency system. Nowadays, most popular multiplayer games are developed using C++, because these modern games have high performance requirements which are best addressed with a relatively low-level, object-oriented programming language. Since the EPM system presented in this paper is used in the field of MMOGs, it is also developed in C++.The paper is organized as follows. In Section II we present the basic MMOG architecture. Section III describes how persistent data can be represented in relational databases. Section IV presents the architectural design of EPM and its methods used for data persistency. We summarize our approach and compare it to related work in Section V.

No abstract