Measurement-based Admission Control Scheme Research Articles

Implementation and Evaluation of Measurement-Based Admission Control Schemes Within a Converged Networks QoS Management Framework

Policy-based network management (PBNM) paradigms provide an effective tool for end-to-end resource management in converged next generation networks by enabling unified, adaptive and scalable solutions that integrate and co-ordinate diverse resource management mechanisms associated with heterogeneous access technologies. In our project, a PBNM framework for end-to-end QoS management in converged networks is being developed. The framework consists of distributed functional entities managed within a policy-based infrastructure to provide QoS and resource management in converged networks. Within any QoS control framework, an effective admission control scheme is essential for maintaining the QoS of flows present in the network. Measurement based admission control (MBAC) and parameter based admission control (PBAC) are two commonly used approaches. This paper presents the implementation and analysis of various measurement-based admission control schemes developed within a Java-based prototype of our policy-based framework. The evaluation is made with real traffic flows on a Linux-based experimental testbed where the current prototype is deployed. Our results show that unlike with classic MBAC or PBAC only schemes, a hybrid approach that combines both methods can simultaneously result in improved admission control and network utilization efficiency.

End-to-end Measurement Based Admission Control VoIP protocol with loss policy

This paper presents a study of the newly proposed End-to-end Measurement Based Admission Control scheme with Loss threshold policy (EMBAC-L). The proposed scheme allows automatic adjustment of the admission control scheme parameters using a feedback measurement of the network’s active loss rate. If the loss rate is less than the predetermined threshold, then the call is accepted, otherwise the call is rejected, with probability P which is a function of the measured network loss. The scheme’s call rejection probability is analyzed with various distribution functions in order to set the admission threshold and scheme parameters to the appropriate operational value. Simulation is used to evaluate the scheme’s performance and to demonstrate its effectiveness. Our study shows that the proposed admission control mechanisms enhance the EMBAC mechanism’s performance, and dynamically control the VoIP packet loss rate under various network operational conditions.

Admission control scheme based on priority access for wireless LANs

In order to support the quality of service (QoS) requirements at the medium access control (MAC) layer, the enhanced distributed channel access (EDCA) has been developed in IEEE 802.11e standard. However, it cannot guarantee the stringent real-time constraints of multimedia applications such as voice and video without an efficient method of controlling network loads. In this paper, we propose a measurement-based admission control scheme, which is made up of two parts: priority access and admission control. First, in order to measure the channel status per traffic type, we propose a priority access mechanism in which each priority traffic is distinguished by a busy tone, and separately performs its own packet transmission operation. Then, admission control mechanism protects existing flows from new ones, and maintains the QoS of the admitted flows based on the measured channel status information. Performance of the proposed scheme is evaluated by simulation. Our results show that the proposed scheme is very effective in guaranteeing the QoS of multimedia applications as well as in avoiding the performance starvation of low priority traffics.

Multi-hop mesh networking for UWB WPANs with QoS support

Currently there are two competing proposals for Ultra-WideBand (UWB): one is DS-UWB based on IEEE 802.15.3 MAC and the other is Multi-Band OFDM Alliance (MBOA). Because of the short-range characteristics of high-speed UWB networks (around 10 m), it is highly desirable to have a multi-hop, range extension technology for future wireless personal area networks. Moreover, QoS is essential to support real-time applications over multi-hop paths in UWB networks. This paper first proposes a mesh network architecture and a simple, low-cost method for establishing communications across multiple piconets via multi-hop connections in 802.15.3 networks. It can be used to extend network coverage through connecting piconets on multiple channels. We then describe a simple, measurement-based admission control scheme for contention access in MBOA UWB networks, which allows high throughputs and low delays for QoS traffic by limiting the traffic load in the network. The admission control decision is based on both on-line measurement and a well-known analytical model of contention-based channel access.

An Admission Control Scheme Based on Online Measurement for VBR Video Streams Over Wireless Home Networks

This paper presents an online measurement-based admission control scheme on the basis that the aggregate VBR video traffic is lognormally distributed. The proposed scheme consists of two components: measurement process and admission decision. The measurement process applies a linear Kalman filter to estimate statistical parameters of aggregate VBR video traffic. The estimated statistical parameters are used to calculate the effective bandwidth for admission decision. Variable bit rate (VBR) video traffic with high data rate is expected to occupy a dominant proportion of bandwidth for future wireless broadband home networks. To guarantee quality-of-service (QoS) of such VBR video streams, while achieving a high level of channel utilization, an efficient admission control scheme is urgently required, especially for emerging wireless multimedia indoor services, such as HDTV, online video game, etc. The proposed scheme is computationally efficient and accurate without much prior traffic information. Simulation results verify its effectiveness and show that it performs well for both a small number of connections and a large number of connections.

An integrated bandwidth allocation and admission control framework for the support of heterogeneous real-time traffic in class-based IP networks

The support of real-time traffic in class-based IP networks requires the reservation of resources in all the links along the end-to-end paths through appropriate queuing and forwarding mechanisms. This resource allocation should be accompanied by appropriate admission control procedures in order to guarantee that newly admitted real-time traffic flows do not cause any violation to the Quality of Service (QoS) experienced by the already established real-time traffic flows. In this paper we initially aim to highlight certain issues with respect to the areas of bandwidth allocation and admission control for the support of real-time traffic in class-based IP networks. We investigate the implications of topological placement of both the bandwidth allocation and admission control schemes. We show that the performance of bandwidth allocation and admission control schemes depends highly on the location of the employed procedures with respect to the end-users requesting the services and the various network boundaries (access, metro, core, etc.). Based on our results we conclude that the strategies for applying these schemes should be location-aware, because the performance of bandwidth allocation and admission control at different points in a class-based IP network, and for the same traffic load, can be quite different and can deviate greatly from the expected performance. Through simulations we also try to provide a quantitative view of the aforementioned deviations. Taking the implications of this “location-awareness” into account, we subsequently present a new Measurement-based Admission Control (MBAC) scheme for real-time traffic that uses measurements of aggregate bandwidth only, without keeping the state of any per-flow information. In this scheme there is no assumption made on the nature of the traffic characteristics of the real-time traffic flows, which can be of heterogeneous nature. Through simulations we show that the admission control scheme is robust with respect to traffic heterogeneity and measurement errors. We also show that our scheme compares favorably against other admission control schemes in the literature.

Predicted Sum: A Robust Measurement-Based Admission Control with Online Traffic Prediction

We present a new measurement-based admission control (MBAC) scheme with online traffic prediction, referred to as predicted sum (PS). A simple adaptive online traffic predictor based on normalized least mean squares (NLMS) algorithm is employed. Our scheme has two unique merits: (1) robustness to traffic characteristics and network environment, and (2) easy and accurate control for the provisioning of network utilization and quality-of-service. The simulation results demonstrate its significant performance enhancement over the well-known MBAC measured sum (MS) scheme

Voice and video transmissions with global data parameter control for the IEEE 802.11e enhance distributed channel access

Best-effort data control and admission control are vital to guarantee quality of service for real-time (voice and video) transmissions in the IEEE 802.11e wireless LANs. In this paper, we propose and study a global data parameter control scheme integrated with a measurement-based admission control scheme for the IEEE 802.11e enhanced distributed channel access. In the proposed global data control scheme, the access point dynamically controls best-effort data parameters of stations globally based on traffic condition. Such a global/centralized data parameter control mechanism provides the best fairness for data transmissions among stations. In the proposed centrally-assisted distributed admission control scheme for voice and video transmissions, stations listen to available budgets from the access point to make decisions on acceptance or rejection of a voice or video stream. Such a scheme provides good differentiation among different access categories and provides good fairness among real-time streams within the same access category. The proposed mechanisms are evaluated via extensive simulations. Studies show that, with the proposed global data control scheme and the admission control scheme, quality of service can be greatly improved while maintaining a good utilization.

Measurement‐based admission control scheme with priority and service classes for application in wireless IP networks

AbstractWireless IP networks will provide voice and data services using IP protocols over the wireless channel. But current IP is unsuitable to provide delay or loss bounds and insufficient to support diverse quality of service, both required by real‐time applications. In order to support real‐time applications in wireless IP networks, in this paper a measurement‐based admission control (MBAC) with priority criteria and service classes is considered. First we have shown the suitability of MBAC in wireless IP networks by comparing its performance with a parameter‐based scheme. Next, we have investigated the performance of strictly policy‐based MBAC and policy plus traffic characteristic‐based MBAC schemes in terms of (1) increasing the user mobility, (2) changing traffic parameters and (3) the presence of greedy users. The efficiency and fairness of each scheme are measured in terms of lower class new and handoff traffic performance. Copyright © 2003 John Wiley & Sons, Ltd.

A service model for guaranteeing packet loss bounds in differentiated services architectures

Differentiated Services (DiffServ) is a proposed architecture for the Internet in which various applications are supported using a simple classification scheme. Packets entering the DiffServ domain are marked depending on the packets' class. Premium service and Assured service are the first two types of services proposed within the DiffServ architecture other than the best effort service. Premium service provides a strict guarantee on users' peak rates, hence delivering the highest Quality of Service (QoS). However, it expected to charge at high rates and also to have low bandwidth utilization. The Assured service provides high priority packets with preferential treatment over low priority packets but without any quantitative QoS guarantees. In this paper, we propose a new service, which we call the Loss bound Guaranteed (LG) service for DiffServ architectures. This service can provide a quantitative QoS guarantee in terms of loss rate. A measurement-based admission control scheme and a signaling protocol are designed to implement the LG service. An extensive simulation model has been developed to study the performance and viability of the LG service model. We have tested a variety of traffic conditions and measurement parameter settings in our simulation. The results show that the LG service can achieve a high level of utilization while still reliably keeping the traffic within the maximum loss rate requirement. Indeed, we show that the DiffServ architecture can provide packet-loss guarantees without the need for explicit resource reservation.

A measurement-based call admission control scheme for ATM networks based on the diffusion approximation

We present a dynamic call admission control method based on the diffusion approximation method. The diffusion approximation method is traditionally used for calculating the effective bandwidth for a number of connections having a certain cell loss requirement. The proposed method has a low implementation overhead since it performs measurements on the aggregate traffic stream at a particular ATM switch as opposed to other methods that need to perform per-source measurements. We provide a study of the performance of the method for specific traffic types using simulation and compare with the performance of the static diffusion approximation effective bandwidth method. We also study the influence of variation in traffic parameters such as the source traffic descriptors, the buffer capacity, and the required cell loss probability on the performance of the method.

Connection Admission Control for PCS-to-Internet Protocol Internetworking

This paper studies the connection admission control for PCS-to-Internet protocol internetworking. In order to provide QoS to the Internet and avoid scalability problems, several recent papers proposed endpoint measurement-based admission control (EMAC) schemes, in which admission decisions are based on measurement results from probe packets exchanged between end hosts. Although EMAC has many desirable features in the wireline networks as shown in previous work, we show in this paper that several distinct characteristics in mobile wireless networks, such as low bandwidth, user mobility, and high bit error rate, make EMAC difficult to implement. Observing that networks offering 3rd-generation (3G) personal communication service (PCS), such as UMTS, already incorporate their own connection admission control functions, we propose a mobile-EMAC (M-EMAC) scheme for PCS-to-IP internetworking. Simulation results show that M-EMAC outperforms EMAC in the wireless domain by improving channel utilization while reducing packet losses.

A framework for robust measurement-based admission control

Measurement-based admission control (MBAC) is an attractive mechanism to concurrently offer quality of service (QoS) to users, without requiring a priori traffic specification and on-line policing. However, several aspects of such a system need to be dearly understood in order to devise robust MBAC schemes, i.e., schemes that can match a given QoS target despite the inherent measurement uncertainty, and without the tuning of external system parameters. We study the impact of measurement uncertainty, flow arrival, departure dynamics, and of estimation memory on the performance of a generic MBAC system in a common analytical framework. We show that a certainty equivalence assumption, i.e., assuming that the measured parameters are the real ones, can grossly compromise the target performance of the system. We quantify the improvement in performance as a function of the length of the estimation window and an adjustment of the target QoS. We demonstrate the existence of a critical time scale over which the impact of admission decisions persists. Our results yield new insights into the performance of MBAC schemes, and represent quantitative and qualitative guidelines for the design of robust schemes.

A framework for robust measurement-based admission control

Measurement-based Admission Control (MBAC) is an attractive mechanism to concurrently offer Quality of Service (QoS) to users, without requiring a-priori traffic specification and on-line policing. However, several aspects of such a system need to be clearly understood in order to devise robust MBAC schemes. Through a sequence of increasingly sophisticated stochastic models, we study the impact of parameter estimation errors, of flow arrival and departure dynamics, and of estimation memory on the performance of an MBAC system.We show that a certainty equivalence assumption, i.e., assuming that the measured parameters are the real ones, can grossly compromise the target performance of the system. We quantify the improvement in performance as a function of the memory size of the estimator and a more conservative choice of the certainty-equivalent parameters. Our results yield valuable new insight into the performance of MBAC schemes, and represent quantitative guidelines for the design of robust schemes.