Measurement-based Admission Control Research Articles

Analyse of Measurement Based Admission Control Methods in IMS Networks and Simulation Principle

This paper deals with the quality of service in IP Multimedia Subsystem networks. The evaluation of Quality o Service (QoS) is done through admission control methods. We analyse various methods, which are based on the traffic measurement. The approach that can be applied in finding the suitable admission control method while considering selected QoS parameters is described. Different important QoS parameters can be defined, however we decided to focus on the loss parameter. In our simulations we have used Simple Sum method. Based on the simulation results, we have used new algorithm. The main difference is that it uses the mechanism of time window for achieving more accurate traffic estimate. Algorithm Measured Sum with implementation of time window T has better ability to predict the traffic fluctuation. Compared to the Simple Sum algorithm it achieves lower link utilisation, but also lower level of loss ratio.

The probability relationship between video’s instantaneous and average aggregate rates

The growing demand for video applications and services has contributed substantially to the increase of video traffic on the Internet. Measurement-based admission control was proposed with the primary aim of eliminating or reducing the need of flow state information; also to control overhead for admission decision and maximize utilization at the potential cost of QoS degradation. Some of the admission algorithms depend on the instantaneous rate for its operation. On the other hand, the average aggregate rate has been proposed to better suit variable rate such as video traffic. In this paper, we investigate the probability relationship between the instantaneous and average aggregate rates for video traffic. A mathematical model has been developed to quantify the probability relationship between both rates and validated through extensive simulations using real video sequences. The average rate was found to be lower than instantaneous for a small number of flows, however there was no pronounced difference for a large number of flows. Furthermore, the difference between both rates increases for fast moving content such as sport or longer measurement time window.

Comparative Studies of Methods for Accurate Hurst Parameter Estimation

Over the last decade the traffic of the packet-based networks shows self-similar or long-range dependent nature. Such behaviour raises issues of accuracy in resource allocation and related guarantee required of QoS parameters for data flow. One of the popular mechanisms for QoS parameters guaranty is Measurement-based Admission Control (MBAC). In it’s turn, the efficiency of the MBAC mechanism is tightly related to the accuracy of traffic parameters estimation. The appropriate buffer size estimation is one of primary tasks in MBAC for QoS parameters guarantee. Hurst parameter which describes the level of self-similarity is used for this purpose. The accuracy of it’s estimation is important as otherwise underutilization or over-saturation of the system may occur that would cause high packet losses. The present paper provides a thorough overview of currently known methods for Hurst parameter estimation and presents research results of accuracy levels of each of them.

Joint In-network Video Rate Adaptation and Measurement-Based Admission Control

The important new revenue opportunities that multimedia services offer to network and service providers come with important management challenges. For providers, it is important to control the vide...

Admission Control in IMS Networks

In our paper there is an emphasis on simulations of admission control methods in MATLAB environment. The main task of admission control method is to make a decision if the connection requiring network access should be accepted to the network or the access should be rejected. If the connection is accepted to the network, the admission control has to ensure that Quality of Service of this connection will be satisfied, as well as Quality of Service of all other existing connections. We have observed several Measurement based admission control algorithms and the result is the identification of the suitable algorithm which can estimate the required bandwidth.

Measurement Based Admission Control Methods in IP Networks

Trends in telecommunications show that customers require still more and more bandwidth. If the telecommunication operators want to be successful, they must invest a lot of money to their infrastructure and they must ensure required quality of service. The telecommunication operators would devote to development in this area. The article deals with quality of service in IP networks. Problems of quality of service can be solved through admission control methods based on measurements. These admission control methods take care of control of incoming traffic load. New flow can be accepted only if needed quality of service is ensured for it and without quality of service breach causing of already accepted flows. In the article were made description of simulations and results of simulations for Voice over IP, constant bit rate and video sources. Simulations were realized in Network simulator 2 environment. These simulations were evaluated on the base of some parameters such as: estimated bandwidth, utilization and loss rate.

Admission Control Methods in IP Networks

Telecommunications operators and research institutions pay close attention to the issue of quality of service. The paper deals with methods of admission control in IP networks, which is only one of the subsets of quality of service. There are two large groups of AC methods: parameter-based admission control and measurement-based admission control. The core of the paper is simulation of AC methods and algorithms for topology model in MATLAB. Our simulations are mainly focused on required bandwidth and loss rates. At the end of the paper there are compared results of simulations.

Joint In-network Video Rate Adaptation and Measurement-Based Admission Control: Algorithm Design and Evaluation

The important new revenue opportunities that multimedia services offer to network and service providers come with important management challenges. For providers, it is important to control the video quality that is offered and perceived by the user, typically known as the quality of experience (QoE). Both admission control and scalable video coding techniques can control the QoE by blocking connections or adapting the video rate but influence each other's performance. In this article, we propose an in-network video rate adaptation mechanism that enables a provider to define a policy on how the video rate adaptation should be performed to maximize the provider's objective (e.g., a maximization of revenue or QoE). We discuss the need for a close interaction of the video rate adaptation algorithm with a measurement based admission control system, allowing to effectively orchestrate both algorithms and timely switch from video rate adaptation to the blocking of connections. We propose two different rate adaptation decision algorithms that calculate which videos need to be adapted: an optimal one in terms of the provider's policy and a heuristic based on the utility of each connection. Through an extensive performance evaluation, we show the impact of both algorithms on the rate adaptation, network utilisation and the stability of the video rate adaptation. We show that both algorithms outperform other configurations with at least 10 %. Moreover, we show that the proposed heuristic is about 500 times faster than the optimal algorithm and experiences only a performance drop of approximately 2 %, given the investigated video delivery scenario.

A QoS-enabled resource management scheme for F-HMIPv6 micro mobility approach

In the near future, wireless networks will certainly run real-time applications with special Quality of Service (QoS) requirements. In this context micro mobility management schemes such as Fast Handovers over Hierarchical Mobile IPv6 (F-HMIPv6) will be a useful tool in reducing Mobile IPv6 (MIPv6) handover disruption and thereby to improve delay and losses. However, F-HMIPv6 alone does not support QoS requirements for real-time applications. Therefore, in order to accomplish this goal, a novel resource management scheme for the Differentiated Services (DiffServ) QoS model is proposed to be used as an add-on to F-HMIPv6. The new resource management scheme combines the F-HMIPv6 functionalities with the DiffServ QoS model and with network congestion control and dynamic reallocation mechanisms in order to accommodate different QoS traffic requirements. This new scheme based on a Measurement-Based Admission Control (MBAC) algorithm is effective, simple, scalable and avoids the well known traditional resource reservation issues such as state maintenance, signaling overhead and processing load. By means of the admission evaluation of new flows and handover flows, it is able to provide the desired QoS requirements for new flows while preserving the QoS of existing ones. The evaluated results show that all QoS metrics analyzed were significantly improved with the new architecture indicating that it is able to provide a highly predictive QoS support to F-HMIPv6.

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.

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 protect video traffic while maximizing the link utilization and avoiding packet loss.

Coordinated session-based admission control with statistical learning for multi-tier internet applications

Popular Internet applications deploy a multi-tier architecture, with each tier provisioning a certain functionality to its preceding tier. In this paper, we address a challenging issue, session-based admission control for peak load management for multi-tier Internet applications. The session-based admission control approach (SBAC) designed for a single Web server is not effective for a multi-tier architecture. This is due to the fact that the bottleneck in a multi-tier website dynamically shifts among tiers as client access patterns change. Admission control based on only the bottleneck tier is not efficient as different sessions impose different resource consumptions at the different tiers. First, we propose a multi-tier measurement based admission control (MBAC), which pro-actively accepts different session mixes based on the utilization state of all tiers. More importantly, we design a coordinated session-based admission control approach (CoSAC) based on a machine learning technique. It uses a Bayesian network to correlate the states of all tiers. The probability with which a session is admitted is determined by the probabilistic inference of the network after applying the evidence in terms of utilization and processing time at each tier to the network. We compare CoSAC with MBAC and a Blackbox approach tailored from SBAC, using the industry standard TPC-W benchmark in a typical three-tier e-commerce website. Experimental results demonstrate the superior performance of CoSAC with respect to the effective session throughput.

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.

Measurement of packet loss probability by optimal design of packet probing experiments

Packet-level measurement is now critical to many aspects of broadband networking, for example for guaranteeing service level agreements, facilitating measurement-based admission control algorithms and performing network tomography. Because it is often impossible to measure all the data passing across a network, the most widely used method of measurement works by injecting probe packets. The probes provide samples of the packet loss and delay, and from these samples the loss and delay performance of the traffic as a whole can be deduced. However, measuring performance like this is prone to errors. Recent work has shown that some of these errors are minimised by using a gamma renewal process as the optimal pattern for the time instants at which to inject probes. This leaves the best rate at which to inject probes as the key unsolved problem, and this is addressed here by using the statistical principles of the design of experiments. The experimental design approach allows one to treat packet-level measurements as numerical experiments that can be designed optimally. Modelling the overflow of buffers as a 2-state Markov chain, the system's likelihood function is deduced, and from this a technique (using the Fisher information matrix) to determine the upper-bound on the optimal rate of probing is developed. A generalisation of this method accounts for the effect of the probed observations interfering with the experiment. The numerical results focus on VoIP traffic, allowing one to show how this methodology would be used in practice. One application of this is in measurement-based admission control algorithms, where the technique can be used to provide an upper-bound on the rate at which probes should be injected to monitor the loss performance of the target network, prior to making an admit/do not admit decision.

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.

Admission of QoS aware users in a smart network

Smart networks have grown out of the need for stable, reliable, and predictable networks that will guarantee packet delivery under Quality of Service (QoS) constraints. In this article we present a measurement-based admission control algorithm that helps control traffic congestion and guarantee QoS throughout the lifetime of a connection. When a new user requests to enter the network, probe packets are sent from the source to the destination to estimate the impact that the new connection will have on the QoS of both the new and the existing users. The algorithm uses a novel algebra of QoS metrics, inspired by Warshall's algorithm, to look for a path with acceptable QoS values to accommodate the new flow. We describe the underlying mathematical principles and present experimental results obtained by evaluating the method in a large laboratory test-bed operating the Cognitive Packet Network (CPN) protocol.

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.

Multi-Class Measurement Based Admission Control for a QoS Framework with Dynamic Resource Management

The advent of a Premium Service (PS) featuring Internet is still pending, mainly due its difficult deployment. But do we really need Quality of Service like PS? Likely no. We are therefore investigating an alternative QoS model, which is more flexible to deploy at the expense of looser QoS guarantees. We call it a Better-than-Best-Effort (BBE) service. What distinguishes our approach from traditional ones is dynamic resource management based on measurements and ruled by Perceptual QoS. What yet has been missing was Admission Control (AC) and in this paper we present our latest advance. Based on the existence of measurements taken by the queueing module, we developed a Measurement Based AC algorithm. Design goal was simplicity and general applicability in terms of independence from statistical assumptions. Likely the most interesting finding is that even a very simple design proofed to be reasonably effective for our BBE service, mainly due to a cross-layer design, i.e. cooperation between dynamic resource management on queuing level and AC. This is the conclusion a comprehensive simulative performance evaluating.