Performance Evaluation of MBAC solutions

Admission control prevents certain flows from accessing a network with regard to the current utilization level of its resources with the ultimate goal of avoiding congestion and performance collapses, so that, accepted flows receive a sufficient level of Quality of Service (QoS). In this paper, we evaluate the performance of three measurement-based admission control (MBAC) solutions in the context of semantic networks, which autonomously acquire a knowledge on the on-going traffic. Each MBAC solution is carefully parameterized to have identical performance target expressed in terms of maximum tolerable loss rate or either queueing delay. We also include the results that would be obtainable by an ideal admission control so as to benchmark the performance of existing MBAC. An extensive set of simulations, using different methods for representing the background traffic, viz. a Poisson process, a PPBP process and a real trace, were carried out to evaluate the performance of each solution. Our results tend to show that, in case of a target loss rate, when the characteristics of background traffic deviate significantly from a "regular" source (e.g., a Poisson process) to more variable sources (e.g., a PPBP process, a real trace), the "Aggregate Traffic Envelopes" and "Equivalent Capacity" solutions brings satisfactory results, much better than those obtained by the "Measured Sum" solution. However, if one deals with a queuing delay target, the outcomes of any MBAC solution are generally less successful, as they typically tend to deviate further from the ideal admission control, often in an overly conservative way

KBAC: Knowledge-Based Admission Control

Many methods have been proposed in the literature to perform admission control in order to provide a sufficient level of Quality of Service (QoS) to accepted flows. In this paper, we introduce a novel data-driven method based on a time-varying model that we refer to as Knowledge-Based Admission Control solution (KBAC). Our KBAC solution consists of three main stages: (i) collect measurements on the on-going traffic over the communication link; (ii) maintain an up-to-date broad view of the link behavior, and feed it to a Knowledge Plane; (iii) model the observed link behavior by a mono-server queue whose parameters are set automatically and which predicts the expected QoS if a flow requesting admission were to be accepted. Our KBAC solution provides a probabilistic guarantee whose admission threshold is either expressed, as a bounded delay or as a bounded loss rate. We run extensive simulations to assess the behavior of our KBAC solution in the case of a delay threshold. The results show that our KBAC solution leads to a good trade-off between flow performance and resource utilization. This ability stems from the quick and automatic adjustment of its admission policy according to the actual variations on the traffic conditions

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

A measurement-based congestion alarm for self-similar traffic

Self-similar traffic is distinguished by positive correlation, which can be exploited for better traffic management. Inspired by measurement-based admission control schemes, a measurement-based congestion alarm is proposed. The aggregate traffic at an output port of a switch or router in a high-speed network is modeled by a fractional Gaussian noise process. Traffic measurements are performed in regular time intervals to determine the current traffic loading. This information is then used to predict the loading situation in the near future. If congestion is likely to occur, a congestion alarm is set off and appropriate network management functions taken to alleviate the possible congestion. The above constitutes a closed loop feedback control mechanism that maintains high resource utilization. Simulation results show that the proposed scheme, when used with dynamic bandwidth allocation, reduces bandwidth requirements by more than 20%.published_or_final_versio

PCN based admission control for autonomic video quality differentiation: design and evaluation

The popularity of multimedia services has introduced important new challenges for broadband access network management. As these services are very prone to network anomalies such as packet loss and jitter, accurate admission control mechanisms are needed to avoid congestion. Traditionally, centralized admission control mechanisms often underperform in combination with multimedia services, as they fail to effectively characterize the amount of needed resources. Recently, measurement based admission control mechanisms have been proposed such as the IETF Pre-Congestion Notification (PCN) mechanism, where the network load is measured at each intermediate node and signaled to the edge, where the admittance decision takes place. In this article, we design a PCN based admission control mechanism, optimized for protecting bursty traffic such as video services, which is currently not studied in the PCN working group. We evaluated and identified the effect of PCN's configuration in protecting bursty traffic. The proposed admission control mechanism features three main improvements to the original PCN mechanism: first, it uses a new measurement algorithm, which is easier to configure for bursty traffic. Second, it allows to automatically adapt PCN's configuration based on the traffic characteristics of the current sessions. Third, it introduces the differentiation between video quality levels to achieve an admission decision per video quality level of each request. The mechanism has been extensively evaluated in a packet switched simulation environment, which shows that the novel admission control mechanism is able to protec

Admission control in multiservice IP networks : architectural issues and trends

The trend toward the integration of current and emerging applications and services in the Internet has launched new challenges regarding service deployment and management. Within service management, admission control (AC) has been recognized as a convenient mechanism to keep services under controlled load and assure the required QoS levels, bringing consistency to the services offered. In this context, this article discusses the role of AC in multiservice IP networks and surveys current and representative AC approaches. We address and compare the architectural principles of these AC approaches and their main features, virtues and limitations that impact on the quality control of network services. We identify important design aspects that contribute to the successful deployment of flexible and scalable AC solutions in multiservice networks

Statistical Service Guarantees for Traffic Scheduling in High-Speed Data Networks

School of Electrical and Computer Engineerin