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Network bandwidth and server capacity are gradually becoming overloaded due to high demand and rapid evolution of high quality multimedia services over the Internet. Internet Protocol Television (IPTV) is among the multimedia services that demand more of network and server resources, especially with the emergence of Mobile IPTV. It is imperative for service providers to maintain good quality management...
Quality of Service (QoS) based scheduling in Cognitive radio networks (CRN) is a pressing research problem. The objective of this work is to study the feasibility of using CRN for delay sensitive applications in the presence of primary users with random ON/OFF periods. The first contribution of this work is the modeling of a cognitive node as a Queuing system and characterization of the average delay...
The paper describes a service model for cost-effective event reporting to clients over a wide-area network. The service provider (SP) maintains multiple protocol mechanisms to replicate the event pages at different proxy nodes of the distribution network. The mechanisms, which embody server-driven and client-driven replica update schemes to synchronize the page copies, reduce the access latency on...
The IP Multimedia Subsystem (IMS) seems to be the technology that will prevail in Next Generation Networks (NGN s), since the interworking environment and the service flexibility that this technology offers to the currently deployed wireless broadband technologies makes it appealing to users, service developers and network operators. In this paper a heterogeneous network model based on the IMS that...
Implications of implementing a local storage within Passive Optical Networks to enhance Video-on-Demand delivery are critically examined in this work. We conduct packet level simulations in order to study enhancements of Quality of Service attributes. Two architectures where the Passive Optical Network is equipped with and without a local storage server are simulated to study the behavior of packet...
Base station (BS) sleep mode operation is one of the effective ways to save energy, but it may lead to longer delay to the customers. In order to evaluate the tradeoffs between energy consumption and customer delay, we model the BS sleep mode operation as an N-policy M/G/1 vacation queue with setup and close-down times, where the BS enters sleep mode if no customers arrive during the close-down time...
Streaming services have grown rapidly in the last few years and providers of video on-demand, such as Netflix or YouTube, are increasing the number of users even more quickly. The majority of these companies implement their services using huge Content Delivery Networks that are as much powerful as expensive, e.g. Amazon and Akamai. In this paper we propose a hybrid CDN/P2P solution that aims at reducing...
This paper investigates and compares the performance of the popular VoIP codecs G.711, G.723.1 and G.729A over an IP network based on SIP architecture, using RTP as a transport protocol. This is based on different simulations in order to evaluate the performance of each codec and to find the optimal codec. For this objective this paper analyzes Quality of service (QoS) parameters, principally delay,...
Nowadays, the end-users have multitude of offers that make service prices decrease in using a network environment with multiple-operators and multiple-network. Consequently, the competition between network providers increases. The customer is today in a strong position with ability to select the best one among different competing providers. Besides similar pricing schemes, which are a useful decision...
Disaster situations are a challenge for network operators because they result in an extraordinary large number of calls being opened simultaneously compared to normal operating conditions. The Quality of Service (QoS) and Quality of Experience (QoE) for the end user can be widely affected by peak loads and result in severe degradation, basically due to congestion on bottlenecks inside the network...
In this paper, we propose a modification of the observe extension of CoAP to include Quality of Service (QoS) support for timeliness. The proposed QoS support is based on delivery priority. Nodes are able to express the priority order with which they wish to be notified. Furthermore, they are also able to specify which notification they want to receive. We classify the notifications in two categories:...
Based on the requirement of the transmission of real-time service in wireless sensor networks, the paper studies Weighted Fair Queuing (WFQ) algorithm profoundly. Having analyzed the reason why WFQ can't ensure the quality of real-time service, it proposes P-WFQ, which is a priority-based Weighted Fair Queuing (P-WFQ) algorithm. With sliding windows, P-WFQ combines WFQ and the priority-based mechanism...
Road maps are important for several applications in vehicular networks. As a consequence, an updated map is essential for a proper behavior of such applications. In this paper, we focus on a map update application based on an infrastructure-to-vehicle communication with a high mobility. In order to understand the application's behavior, we analyze different performance criteria: System Goodput, Packet...
VoIP is replacing traditional telephony system over PSTN as a more affordable communication tool on account of convergence of networks. Meanwhile, security issue brings more attention and becomes more important. SIP is based on text message. This makes the protocol easy to implement but also creates opportunity for hackers to steal or modify the messages. There exist a various approaches to secure...
Electronic learning has produced a comfortable, sophisticated, interactive and adaptable teaching model. Moreover, the consistent technical progress in this field allows the development of increasingly interesting applications [1]. We chose to select those elements to create an e-learning environment. This paper presents a model of the multi-tiered e-learning system based on Web Services. It shows...
The full coverage of continuous voice cloud services is still an open issue in an overlapping network, particularly with regard to heterogeneously public communication network infrastructures. However, hardly anyone of today's service providers offers seamless voice call continuity across these networks due to the high technical integration effort and economic cost. Given this backdrop, we present...
As the demand for multimedia traffic via satellite increase, quality of service (QoS) management becomes more crucial, especially for the effective utilization of on-board switching capabilities of multi-beam satellite system. For multimedia services, parameters related to different requirements need to be evaluated in terms of delay, jitter, blocking probability and burstiness. This paper is on the...
Online videos are one of the most prevalent forms of communication over the Internet because humans are attracted to visual stimulations. Multimedia services, especially real-time services, require data to arrive on time. Unlike any other transmissions, video streaming needs to be monitored and adapted to bandwidth, when the video stream passes through the best-effort environment. A guaranteed QoS...
We propose an extension of WFQ, called BWFQ, to reduce the computation time and guarantee the QoS performances as well. Simplifications of the WFQ algorithm may degrade the performance of all sessions. Instead, BWFQ dynamically aggregates packets in advance and performs scheduling in unit of block. Block size is controlled by a parameter called granule. Each session has a granule setting in accordance...
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