Search results for "quality of service"
showing 10 items of 194 documents
Web Server Support for e-Customer Loyalty through QoS Differentiation
2013
The paper deals with the problem of offering predictive service in e-commerce Web server systems under overload. Due to unpredictability of Web accesses, such systems often fail to effectively handle peak traffic, which results in long delays and incomplete transactions. As a consequence, online retailers miss an opportunity to attract new customers, retain the loyalty of regular customers, and increase profits. We propose a method for priority-based admission control and scheduling of requests at the Web server system in order to differentiate Quality of Service (QoS) with regard to user-perceived delays, i.e., Web page response times provided by the system (as opposed to HTTP request resp…
Supporting scalable video transmission in MANETs through distributed admission control mechanisms
2009
Emerging multimedia applications over mobile devices are becoming very popular, especially over infrastructure wireless networks such as cellular and WLANs. However, providing this kind of services over infrastructureless networks like ad hoc networks presents many additional problems. One of these problems is how to share resources fairly among the users involved. In this article we propose a QoS framework supporting scalable video streaming in mobile ad hoc networks based on distributed admission control and video traffic awareness. Our framework promotes fairness between video flows in terms of resource consumption. It also guarantees a significant reduction of the idle times experienced…
Ensuring the QoS requirements in 802.16 scheduling
2006
IEEE 802.16 standard defines the wireless broadband access network technology called WiMAX. WiMAX introduces several interesting advantages, and one of them is the support for QoS at the MAC level. For these purposes, the base station must allocate slots based on some algorithm. We propose a simple, yet efficient, solution for the WiMAX base station that is capable of allocating slots based on the QoS requirements, bandwidth request sizes, and the WiMAX network parameters. To test the proposed solution, we have implemented the WiMAX MAC layer in the NS-2 simulator. Several simulation scenarios are presented that demonstrate how the scheduling solution allocates resources in various cases. S…
WINSE: WiMAX NS-2 extension
2009
IEEE 802.16 standard defines the wireless broadband technology called WiMAX. When compared to other wireless technologies, it introduces many interesting advantages at PHY, MAC, and QoS layers. Heavy simulations are needed to study IEEE 802.16 performance and propose further enhancements to this standard. Link level simulations are not always sufficient, while system level simulators are not always accurate to capture MAC and transport protocol details. We implemented a 802.16 extension for the NS-2 network simulator. It includes upper PHY modeling, almost all the features of the 802.16 MAC layer, as well as the QoS framework. This article describes the implemented features, simulation meth…
Significance of channel failures on network performance in CRNs with reserved spectrum
2016
It is well understood that in wireless networks, channel failures, which are typically caused by equipment or power failures as well as intrinsic features in radio transmissions, such as fading and shadowing, can easily result in network performance degradation. Therefore, fast recovery from channel failures is an important measure that should be incorporated with those networks. Consequently, in a cognitive radio network (CRN), channel failures can cause significant performance degradation in both primary and secondary networks. Instead, retainability, i.e., the capability of providing continuous connection for users must be guaranteed even if a significant network element is disrupted. In…
An analytical study of mixed backoff schemes for QoS differentiation in wireless LAN
2009
In this paper, we propose an analytical model to evaluate performances of a wireless network composed by two groups of nodes using two different backoff schemes for channel access. The two different backoff schemes are used for QoS differentiation in term of priority. Our analysis results show that the priority group can have its performances enhanced, in term of saturation throughput and delay, without significant degradation of normal group nodes performances. This enhancement is also noticed for throughput efficiency at system level.
Generating and Instantiating Abstract Workflows with QoS User Requirements
2017
The growing availability of services accessible through the network makes it possible to build complex applications resulting from their composition that are usually characterized also by non-functional properties, known as Quality of Service (QoS). To exploit the full potential of service technology, automatic QoS-based composition of services is crucial. In this work a framework for automatic service composition is presented that relies on planning and service negotiation techniques for addressing both functional and non-functional requirements. The proposed approach allows for dynamic service composition and QoS attributes, and it can be applied when services are provided in the contest …
The Quality of Service Issue in Virtual Environments
2011
Networked virtual environments (NVEs) have become a major trend in distributed computing, mainly due to the enormous popularity of multi-player online games in the entertainment industry. Nowadays, NVE systems are considered as the supporting technology for many networked and virtual organizations (NVO) (Singhal & Zyda, 1999), especially to those classified within the field of computer supported cooperative work (CSCW), where networked computer can be seen as a standard to provide the technological means to support the team design (Ott & Nastansky, 1997). These highly interactive systems simulate a virtual world where multiple users share the same scenario. The system renders the im…
User requirements and resource control for cooperative multimedia applications
1997
The spread of distributed multimedia applications is setting forth a new set of challenges in the management of host and network resources for guaranteeing Quality of Service (QoS). When the multimedia applications compete for resources as in the case of a cooperative multimedia environment, the management task becomes even more difficult. In this work, we first discuss QoS for multimedia applications. We then present the architectural and implementation details of a Cooperative Multimedia Environment (CME) made up of Cooperative Multimedia Applications (COMMA), one for each user. A COMMA presents a user with a single interface that allows him to invite other users to a cooperative session,…
Resource Self-management under an SLA within a Cloud Networking Environment
2015
International audience; Today, cloud networking is one of the recent research areas in the cloud computing research communities. The main drawback of cloud networking consists in the lack of Quality of Service (QoS) guarantee and management in conformance with a corresponding Service Level Agreement (SLA). In this paper, we propose a framework for self-establishing an end-to-end SLA between a Cloud Service User (CSU) and several Cloud Service Providers (CSPs) in a cloud networking environment (inter-cloud Broker and Federation architecture). Then, we propose the self-management of cloud resources under the established SLA using specific autonomic cloud managers. We simulate our proposed fra…