Improving QoS guarantees through implicit AC

http://www2.dcc.ufmg.br/eventos/noms2008/In multiservice networks, admission control (AC) is a convenient means of assuring high quality communications by safeguarding enough availability for customer traffic. This can be particularly useful to preserve the quality of services such as IP telephony and video conferencing, and to ensure acceptable throughput to elastic flows. This paper tackles the problematic of performing implicit AC in multiservice networks, pointing out a flexible yet simple to deploy solution for controlling flows which do not explicitly send signaling admission requests. This allows to complement the explicit AC case, widening the ability to integrate services and applications in a transparent way. The versatility and self-adaptability of the proposed distributed AC criteria in ensuring the quality of multiple services is also proved

The role of admission control in assuring multiple services quality

Considering that network overprovisioning by itself is not always an attainable and everlasting solution, Admission Control (AC) mechanisms are recommended to keep network load controlled and assure the required service quality levels. This article debates the role of AC in multiservice IP networks, providing an overview and discussion of current and representative AC approaches, highlighting their main characteristics, pros and cons regarding the management of network services quality. In this debate, particular emphasis is given to an enhanced monitoring-based AC proposal for assuring multiple service levels in multiclass networks.Centro de Ciências e Tecnologias da Computação do Departamento de Informática da Universidade do Minho (CCTC

Toward scalable management of multiple service levels in IP networks

This paper analyzes and discusses the role of a distributed and simple admission control (AC) model in achieving scalable management of multiple network service levels. The model design, covering explicit and implicit AC, exhibits relevant properties which allow managing QoS and SLSs in multiservice IP networks in a flexible and scalable manner. These properties stem from the way service-dependent AC and on-line service performance monitoring are proposed and articulated in the model's architecture and operation. The scalability debate, carried out at these two levels, highlights key steps toward performing self-adaptive service-oriented AC and low overhead multiservice monitoring. The performance evaluation results, illustrating the role and relevance of the defined AC rules, show that QoS and SLSs requirements can be efficiently satisfied or bounded, proving that the simplicity, flexibility and self-adaptability of the model can be explored to manage multiple service guarantees successfully

Energy Efficient and Reliable ARQ Scheme (ER-ACK) for Mission Critical M2M/IoT Services

Wireless sensor networks (WSNs) are the main infrastructure for machine to machine (M2M) and Internet of thing (IoT). Since various sophisticated M2M/IoT services have their own quality-of-service (QoS) requirements, reliable data transmission in WSNs is becoming more important. However, WSNs have strict constraints on resources due to the crowded wireless frequency, which results in high collision probability. Therefore a more efficient data delivering scheme that minimizes both the transmission delay and energy consumption is required. This paper proposes energy efficient and reliable data transmission ARQ scheme, called energy efficient and reliable ACK (ER-ACK), to minimize transmission delay and energy consumption at the same time. The proposed scheme has three aspects of advantages compared to the legacy ARQ schemes such as ACK, NACK and implicit-ACK (I-ACK). It consumes smaller energy than ACK, has smaller transmission delay than NACK, and prevents the duplicated retransmission problem of I-ACK. In addition, resource considered reliability (RCR) is suggested to quantify the improvement of the proposed scheme, and mathematical analysis of the transmission delay and energy consumption are also presented. The simulation results show that the ER-ACK scheme achieves high RCR by significantly reducing transmission delay and energy consumption

Self-adaptive distributed management of QoS and SLSs in multiservice networks

Apresentação efectuada na International Conference on Integrated Management (IM 2005), Nice, France, May 2005.Distributed service-oriented traffic control mechanisms, operating with minimum impact on network performance, assume a crucial role as regards controlling services quality and network resources transparent and efficiently. In this way, we describe and specify a lightweight distributed admission control (AC) model which provides an uniform solution for managing QoS and SLSs in multiclass and multidomain environments. Taking advantage of the consensual need of on-line service monitoring and traffic control at the network edges, AC decisions are driven by feedback from systematic edge-to-edge measurements of relevant QoS parameters for each service type and SLS utilization. This allows self-adaptive service and resource management, while abstracting from network core complexity and heterogeneity. In this paper, introducing an expressive notation, we specify the high-level entities for multiservice provisioning in a domain and formalize service-dependent AC equations to assure both intra and interdomain model operation. A proof-of-concept of the AC criteria effectiveness in satisfying each service class commitments while achieving high network utilization is provided through simulation

Improving Macrocell - Small Cell Coexistence through Adaptive Interference Draining

The deployment of underlay small base stations (SBSs) is expected to significantly boost the spectrum efficiency and the coverage of next-generation cellular networks. However, the coexistence of SBSs underlaid to an existing macro-cellular network faces important challenges, notably in terms of spectrum sharing and interference management. In this paper, we propose a novel game-theoretic model that enables the SBSs to optimize their transmission rates by making decisions on the resource occupation jointly in the frequency and spatial domains. This procedure, known as interference draining, is performed among cooperative SBSs and allows to drastically reduce the interference experienced by both macro- and small cell users. At the macrocell side, we consider a modified water-filling policy for the power allocation that allows each macrocell user (MUE) to focus the transmissions on the degrees of freedom over which the MUE experiences the best channel and interference conditions. This approach not only represents an effective way to decrease the received interference at the MUEs but also grants the SBSs tier additional transmission opportunities and allows for a more agile interference management. Simulation results show that the proposed approach yields significant gains at both macrocell and small cell tiers, in terms of average achievable rate per user, reaching up to 37%, relative to the non-cooperative case, for a network with 150 MUEs and 200 SBSs

A service-oriented admission control strategy for class-based IP networks

The clear trend toward the integration of current and emerging applications and services in the Internet launches new demands on service deployment and management. Distributed service-oriented traffic control mechanisms, operating with minimum impact on network performance, assume a crucial role as regards controlling services quality and network resources transparently and efficiently. In this paper, we describe and specify a lightweight distributed admission control (AC) model based on per-class monitoring feedback for ensuring the quality of distinct service levels in multiclass and multidomain environments. The model design, covering explicit and implicit AC, exhibits relevant properties that allow managing quality of service (QoS) and service-level specifications (SLSs) in multiservice IP networks in a flexible and scalable manner. These properties, stemming from the way service-dependent AC and on-line service performance monitoring are proposed and articulated in the model’s architecture and operation, allow a self-adaptive service and resource management, while abstracting from network core complexity and heterogeneity. A proof of concept is provided to illustrate the AC criteria ability in satisfying multiple service class commitments efficiently. The obtained results show that the self-adaptive behavior inherent to on-line measurement-based service management, combined with the established AC rules, is effective in controlling each class QoS and SLS commitments consistently

Grid simulation services for the medical community

The first part of this paper presents a selection of medical simulation applications, including image reconstruction, near real-time registration for neuro-surgery, enhanced dose distribution calculation for radio-therapy, inhaled drug delivery prediction, plastic surgery planning and cardio-vascular system simulation. The latter two topics are discussed in some detail. In the second part, we show how such services can be made available to the clinical practitioner using Grid technology. We discuss the developments and experience made during the EU project GEMSS, which provides reliable, efficient, secure and lawful medical Grid services

Ensuring IP services consistency through lightweight monitoring-based admission control

This paper evaluates the performance of a distributed and lightweight AC model based on per-class edge-to-edge monitoring feedback for ensuring the quality of multiple services in class-based IP networks. The model resorts to service-dependent AC rules for controlling QoS parameters and SLSs utilization, both intradomain and end-to-end. To provide a proof-of-concept of the proposed AC solution, a prototype of the AC model has been developed and tested using a simulation platform. The devised test scenarios aim at exploring the AC criteria's ability in satisfying each service class QoS levels and existing SLSs commitments. Generically, the results show that the proposed AC model, using a two-rule AC criterion defined on a service class basis, is able to control service levels and achieve high network utilization, without adding significant complexity to the network elements. The use of systematic edge-to-edge on-line monitoring and of a controlled degree of overprovisioning proved to be essential design aspects contributing for reaching a good compromise between simplicity and performance.Fundação para a Ciência e Tecnologia FC