Página 1 dos resultados de 39 itens digitais encontrados em 0.006 segundos

## Connection Admission Control for a WDM Optical Network Based on Traffic Monitoring and Bandwidth Release

ALMEIDA, Helvecio M.; QUEIROZ, Eduardo M. G. de; CESAR, Amilcar C.
Fonte: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC Publicador: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
96.1%
We proposed a connection admission control (CAC) to monitor the traffic in a multi-rate WDM optical network. The CAC searches for the shortest path connecting source and destination nodes, assigns wavelengths with enough bandwidth to serve the requests, supervises the traffic in the most required nodes, and if needed activates a reserved wavelength to release bandwidth according to traffic demand. We used a scale-free network topology, which includes highly connected nodes ( hubs), to enhance the monitoring procedure. Numerical results obtained from computational simulations show improved network performance evaluated in terms of blocking probability.; Brazilian agency CNPq; Brazilian agency CAPES

## Performance analysis of an optical network employing waveband and traffic grooming

ALMEIDA, Helvecio M.; QUEIROZ, Eduardo M. G. de; ALOIA, Eduardo J.; ROMERO, Murilo A.; CESAR, Amilcar C.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
65.96%
This paper analyses an optical network architecture composed by an arrangement of nodes equipped with multi-granular optical cross-connects (MG-OXCs) in addition to the usual optical cross-connects (OXCs). Then, selected network nodes can perform both waveband as well as traffic grooming operations and our goal is to assess the improvement on network performance brought by these additional capabilities. Specifically, the influence of the MG-OXC multi-granularity on the blocking probability is evaluated for 16 classes of service over a network based on the NSFNet topology. A mechanism of fairness in bandwidth capacity is also added to the connection admission control to manage the blocking probabilities of all kind of bandwidth requirements. Comprehensive computational simulation are carried out to compare eight distinct node architectures, showing that an adequate combination of waveband and single-wavelength ports of the MG-OXCs and OXCs allow a more efficient operation of a WDM optical network carrying multi-rate traffic.; National Council for Scientific and Technological Development (CNPq)[306752/2006-9]; National Council for Scientific and Technological Development (CNPq)[303008/2008-3]; State of Sao Paulo Research Foundation (FAPESP)[03/08269-7]; Coordination for the Improvement of Higher Level Personnel (CAPES)

## Contribuições para a análise e simulação de redes ópticas: aspectos de Engenharia de Tráfego, restauração dinâmica e conversão de comprimentos de onda; Contributions for the analysis and simulation of optical networks: aspects of traffic engineering, dynamic restoration and conversion of wavelenghts

Aloia, Eduardo José
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Relevância na Pesquisa
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## Estudo de algoritmos de controle de admissão em servidores Web distribuídos com QoS; Study of admission control algorithms on QoS distibuted web server

Eustaquio, Paulo Sérgio Franco
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Relevância na Pesquisa
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## Contribuições ao calculo de banda e de probabilidade de perda para trafego multifractal de redes; Contributions to the effective bandwidth and loss probability computing for multifractal network traffic

Flavio Henrique Teles Vieira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Relevância na Pesquisa
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## Estudo de metodos de controle de admissão de chamadas em redes ATM com analise de desempenho

Henrique Antonio Mielli Camargo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Relevância na Pesquisa
36.05%

## Estudo comparativo de algoritmos de CAC para redes ATM

Niudomar Siqueira de Araujo Chaves
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Relevância na Pesquisa
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## Mecanismos para provisão de qualidade de serviço em redes IEEE 802.16; Mechanisms for quality of service provision in IEEE 802.16 networks

Juliana Freitag Borin
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Relevância na Pesquisa
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## B-ISDN connection admission control and routing strategy with traffic prediction by neural networks

Neves, Joaquim E.; Almeida, Luís B.; Leitão, Mário J.
Fonte: IEEE Press Publicador: IEEE Press
Tipo: Conferência ou Objeto de Conferência
Relevância na Pesquisa
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The resource allocation in the Broadband Integrated Services Digital Network (B-ISDN) can be based in an overall network performance function described in this paper and named quality of operation. The quality of operation function is determined itself by bandwidth and quality of service functions. The traffic patterns of the quality of service for each call are predicted by neural networks. The applicability of the quality of operation function to connection admission control and call routing is proposed and supported by simulation results.

## Neural networks in B-ISDN flow control : ATM traffic prediction or network modeling?

Neves, Joaquim E.; Leitão, Mário J.; Almeida, Luís B.
Fonte: IEEE Communications Society Publicador: IEEE Communications Society
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.78%
The authors discuss a technique that offers the combination of shared bandwidth and rejection rate parameters, together with the quality of service predicted by neural networks in a novel strategy for connection admission control and call routing.

## A testbed for network performance evaluation and its application to connection admission control algorithms

Martinello,Magnos; Silva,Edmundo de Souza e
Tipo: Artigo de Revista Científica Formato: text/html
Relevância na Pesquisa
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Multimedia networks will support a wide range of applications with different requirements and traffic characteristics. Connection Admission Control (CAC) algorithms are used to decide whether an incoming connection should be accepted or rejected in order to maintain the quality of service (QoS) demanded by the applications. The objective of this work is to present an environment we developed useful for performance analysis, measurements and experimentation, in particular for testing resource usage based on different traffic characteristics. We demonstrate how a study of the effectiveness of different CAC algorithms can be performed from measurements collected using an ATM switch and the tools we developed. For the studies we selected and implemented two CAC algorithms, one for a non-regulated traffic, proposed by [14], and other for a leaky-bucket regulated traffic, proposed by [5]. The environment tools include a traffic generator supporting IP and native-ATM as well as a CAC module that implements the algorithms above and can be used in conjunction with our test environment. These tools are currently part of the Tangram-II modeling environment [3,11] and available to download.

## Proposta de algoritmo de controle de admissão de conexões baseado em Threshold para as Redes IEEE 802.16; Proposed threshold-based connection admission control (CAC) algorithm for IEEE 802.16 networks

Soares, Claiton Luiz
Tipo: Dissertação
Português
Relevância na Pesquisa
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## Proposta de um mecanismo de policiamento de tráfego baseado em Token Bucket para redes IEEE 802.16

Moraes, Henaldo Barros
Tipo: Dissertação
Português
Relevância na Pesquisa
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## Reinforcement Learning Algorithms for Technology Independent Resource Management in Next Generation Networks:Connection Admission Control Procedures

MIGNANTI, SILVANO
Português
Relevância na Pesquisa
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## Cross-layer design of admission control policies in code division multiple access communications systems utilizing beamforming

Sheng, Wei
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 580279 bytes; application/pdf
Português
Relevância na Pesquisa
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To meet growing demand for wireless access to multimedia traffic, future generations of wireless networks need to provide heterogenous services with high data rate and guaranteed quality-of-service (QoS). Many enabling technologies to ensure QoS have been investigated, including cross-layer admission control (AC), error control and congestion control. In this thesis, we study the cross-layer AC problem. While previous research focuses on single-antenna systems, which does not capitalize on the significant benefits provided by multiple antenna systems, in this thesis we investigate cross-layer AC policy for a code-division-multiple-access (CDMA) system with antenna arrays at the base station (BS). Automatic retransmission request (ARQ) schemes are also exploited to further improve the spectral efficiency. In the first part, a circuit-switched network is considered and an exact outage probability is developed, which is then employed to derive the optimal call admission control (CAC) policy by formulating a constrained semi-Markov decision process (SMDP). The derived optimal policy can maximize the system throughput with guaranteed QoS requirements in both physical and network layers. In the second part, a suboptimal low-complexity CAC policy is proposed based on an approximate power control feasibility condition (PCFC) and a reduced-outage-probability algorithm. Comparison between optimal and suboptimal CAC policies shows that the suboptimal CAC policy can significantly reduce the computational complexity at a cost of degraded performance. In the third part...

## Necessity of Future Information in Admission Control

Xu, Kuang
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.87%
We study the necessity of predictive information in a class of queueing admission control problems, where a system manager is allowed to divert incoming jobs up to a fixed rate, in order to minimize the queueing delay experienced by the admitted jobs. Spencer et al. (2014) show that the system's delay performance can be significantly improved by having access to future information in the form of a lookahead window, during which the times of future arrivals and services are revealed. They prove that, while delay under an optimal online policy diverges to infinity in the heavy-traffic regime, it can stay bounded by making use of future information. However, the diversion polices of Spencer et al. (2014) require the length of the lookahead window to grow to infinity at a non-trivial rate in the heavy-traffic regime, and it remained open whether substantial performance improvement could still be achieved with less future information. We resolve this question to a large extent by establishing an asymptotically tight lower bound on how much future information is necessary to achieve superior performance, which matches the upper bound of Spencer et al. (2014) up to a constant multiplicative factor. Our result hence demonstrates that the system's heavy-traffic delay performance is highly sensitive to the amount of future information available. Our proof is based on analyzing certain excursion probabilities of the input sample paths...

## Performance Modelling and Analysis of Connection Admission Control in OFDMA based WiMAX System with MMPP Queuing

Bouchti, Abdelali El; Kafhali, Said El; Haqiq, Abdelkrim
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.17%
This paper presents a problem of queuing theoretic performance modeling and analysis of Orthogonal Frequency Division Multiple Access (OFDMA) under broad-band wireless networks. We consider a single-cell WiMAX environment in which the base station allocates sub channels to the subscriber stations in its coverage area. The sub channels allocated to a subscriber station are shared by multiple connections at that subscriber station. To ensure the Quality of Service (QoS) performances, two Connection Admission Control (CAC) schemes, namely, threshold-based and queue-aware CAC schemes are considered at a subscriber station. A queuing analytical framework for these admission control schemes is presented considering OFDMA-based transmission at the physical layer. Then, based on the queuing model, both the connection-level and the packetlevel performances are studied and compared with their analogues in the case without CAC. The connection arrival is modeled by a Poisson process and the packet arrival for a connection by a Markov Modulated Poisson Process (MMPP). We determine analytically and numerically different performance parameters, such as connection blocking probability, average number of ongoing connections, average queue length, packet dropping probability...

## Analysis of Quality of Service Performances of Connection Admission Control Mechanisms in OFDMA IEEE 802.16 Network using BMAP Queuing

Bouchti, Abdelali El; Haqiq, Abdelkrim; Kafhali, Said El
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.17%
In this paper, we consider a single-cell IEEE 802.16 environment in which the base station allocates subchannels to the subscriber stations in its coverage area. The subchannels allocated to a subscriber station are shared by multiple connections at that subscriber station. To ensure the Quality of Service (QoS) performances, two Connection Admission Control (CAC) mechanisms, namely, threshold-based and queue-aware CAC mechanisms are considered at a subscriber station. A queuing analytical framework for these admission control mechanisms is presented considering Orthogonal Frequency Division Multiple Access (OFDMA) based transmission at the physical layer. Then, based on the queuing model, both the connection-level and the packet-level performances are studied and compared with their analogues in the case without CAC. The connection arrival is modeled by a Poisson process and the packet arrival for a connection by Batch Markov Arrival Process (BMAP). We determine analytically and numerically different QoS performance measures (connection blocking probability, average number of ongoing connections, average queue length, packet dropping probability, queue throughput and average packet delay).; Comment: 9 pages, This paper has been published in the International Journal of Computer Science Issues...

## Performance Analysis of Connection Admission Control Scheme in IEEE 802.16 OFDMA Networks

Bouchti, Abdelali El; Kafhali, Said El; Haqiq, Abdelkrim
Tipo: Artigo de Revista Científica
We consider a heterogeneous cellular network with densely underlaid small cell access points (SAPs). Wireless backhaul provides the data connection from the core network to SAPs. To serve as many SAPs and their corresponding users as possible with guaranteed data rates, admission control of SAPs needs to be performed in wireless backhaul. Such a problem involves joint design of transmit beamformers, power control, and selection of SAPs. In order to tackle such a difficult problem, we apply $\ell_1$-relaxation and propose an iterative algorithm for the $\ell_1$-relaxed problem. The selection of SAPs is made based on the outputs of the iterative algorithm. This algorithm is fast and enjoys low complexity for small-to-medium sized systems. However, its solution depends on the actual channel state information, and resuming the algorithm for each new channel realization may be unrealistic for large systems. Therefore, we make use of random matrix theory and also propose an iterative algorithm for large systems. Such a large system iterative algorithm produces asymptotically optimum solution for the $\ell_1$-relaxed problem, which only requires large-scale channel coefficients irrespective of the actual channel realization. Near optimum results are achieved by our proposed algorithms in simulations.; Comment: Submitted to IEEE Journal on Selected Areas in Communications...