Random Early Detection Research Articles

프레임 기반 스케줄러를 위한 주기적 패킷 폐기 기법

This paper introduces waiting time based periodic packet discard policy for frame based scheduler. This policy can be used with conventional packet discard policy or buffer management schemes, such as drop-tail or random early detection. Proposed discard policy discards packets, which are stayed in the buffer longer than threshold, at every period of scheduling. This decision of discard is based on waiting time of packet. In this paper, mathematical analysis is performed with situation of network congestion. Also, the simulation is performed to evaluate the performance of proposed discard policy. In the result, proposed discard policy can limit queuing delay by threshold. Also, if the packet discard is performed before scheduling and threshold is set with smaller value than frame length, it can limit the throughput of traffic.

Analytical Modelling and Optimization of Congestion Control for Prioritized Multi-Class Self-Similar Traffic

Traffic congestion in communication networks can dramatically deteriorate user-perceived Quality-of-Service (QoS). The integration of the Random Early Detection (RED) and priority scheduling mechanisms is a promising scheme for congestion control and provisioning of differentiated QoS required by multimedia applications. Although analytical modelling of RED congestion control has received significant research efforts, the performance models reported in the current literature were primarily restricted to the RED algorithm only without consideration of traffic scheduling scheme for QoS differentiation. Moreover, for analytical tractability, these models were developed under the simplified assumption that the traffic follows Short-Range-Dependent (SRD) arrival processes (e.g., Poisson or Markov processes), which are unable to capture the self-similar nature (i.e., scale-invariant burstiness) of multimedia traffic in modern communication networks. To fill these gaps, this paper presents a new analytical model of RED congestion control for prioritized multi-class self-similar traffic. The closed-form expressions for the loss probability of individual traffic classes are derived. The effectiveness and accuracy of the model are validated through extensive comparison between analytical and simulation results. To illustrate its application, the model is adopted as a cost-effective tool to investigate the optimal threshold configuration and minimize the required buffer space with congestion control.

Performance Measurement of TCP and UDP Using Different Queuing Algorithm in High Speed Local Area Network

In the current high speed networks, it is increasingly important to have mechanisms that keep throughput high but average queue sizes low. The queue management algorithm, which is applied to a router, plays an important role in providing Quality of Service (QoS). This paper present a Simulation-based performance Evaluation of two well known transport layer protocol TCP and UDP using two popular queue management methods; Random Early Detection (RED) and Drop Tail, in terms of throughput, queuing delay, packet drop rate and bandwidth utilization. In this paper we study the effect of buffer behavior on each one of these QoS measurements. TCP, UDP and shared topology scenarios are simulated by considering varying number of client case topologies and also the effect of performance in TCP and UDP with increasing the number of client. This simulation report is useful for implementing the queue management algorithm in router based on the traffic type and bandwidth. Index Terms—TCP, UDP, drop tail, RED queue, bandwidth delay product, throughput and end-to-end delay.

Active Queue Management: A Survey

Since its formal introduction to IP networks in 1993 as a viable complementary approach for congestion control, there has been a steady stream of research output with respect to Active Queue Management (AQM). This survey attempts to travel the trajectory of AQM research from 1993 with the first algorithm, Random Early Detection (RED), to current work in 2011. In this survey we discuss the general attributes of AQM schemes, and the design approaches taken such as heuristic, control-theoretic and deterministic optimization. Of interest is the role of AQM in QoS provisioning particularly in the DiffServ context, as well as the role of AQM in the wireless domain. For each section, example algorithms from the research literature are presented.

An Access Point-Based FEC Mechanism for Video Transmission Over Wireless LANs

Forward Error Correction (FEC) is one of the most common means of performing packet error recovery in data transmissions. FEC schemes typically tune the FEC rate in accordance with feedback information provided by the receiver. However, the feedback and FEC rate calculation processes inevitably have a finite duration, and thus the FEC rate implemented at the sender may not accurately reflect the current state of the network. Thus, this paper proposes an Enhanced Random Early Detection Forward Error Correction (ERED-FEC) mechanism to improve the quality of video transmissions over Wireless Local Area Networks (WLANs). In contrast to most FEC schemes, the FEC redundancy rate is calculated directly at the Access Point (AP). Moreover, the redundancy rate is tuned in accordance with both the wireless channel condition (as indicated by the number of packet retransmissions) and the network traffic load (as indicated by the AP queue length). The experimental results show that the proposed ERED-FEC mechanism achieves a significant improvement in the video quality compared to existing FEC schemes without introducing an excessive number of redundant packets into the network.

Easing Congestion in Computer Networks using the Receiver-Window Modification (RWM) Scheme

Random Early Detection (RED), Adaptive RED (ARED), BLUE and other Active Queue Management (AQM) queues have been proposed to replace drop-tail queues for Transmission Control Protocol/Internet Protocol (TCP/IP) networks to ease network congestion. Together with the Exp licit Congestion Notification (ECN) scheme, they had shown some pro mise over the drop tail queues. However, the timeout mechanism or the duration of the reception of three duplicate acknowledgements (ACKs), due to early-dropped packets, delays the response time of TCP in reducing the network congestion. Moreover, using ECN has its downsides: i) its messages may get lost; and ii) TCP implementations at the source, router and the destination have to be ECN-co mpliant (which presents a significant problem in today's implementations). To minimize these problems, this paper presents a novel AQM modification scheme called Receiver-W indow Modification (RWM), wh ich can be used together with any AQM queue for congestion avoidance in packet switched networks, especially at ingress and gateway routers. RWM improves on the average queue sizes, one-way end-to-end packet delays, delay jitter, throughput and number of dropped packets. It also overcomes the dependency of these AQM queues on the queues of downstream routers since ECN messages may get dropped or delayed due to congestion at these routers. We carry out extensive NS2 simulat ions to show our results and to support our claims.

ENHANCEMENT OF QUALITY OF SERVICE PARAMETERS IN WIMAX MOBILE NETWORKS

Next generation mobile networks are expected to provide seamless personal mobile communication and QoS. Since the demands for high speed Internet access as well as multimedia service had increased for last mile broadband access, the Scheduling is one of the most important components of BWA systems that affect system QoS provided to users. Priority queuing gives better throughput than the existing scheme. The IEEE 802.16 standard is a rapidly developing technology for broadband wireless access system. It supports QoS and has very high transmission rate. WiMAX is a standard wireless technology which is used to improve internet access and the multimedia services at very high speed to the end user. The purpose of QoS is to provide a definitive connection to the users who are intrested to connect to the WiMAX tower. In this study we propose a scheme to improve the QoS in the WiMAX system by increasing the throughput and decreasing the jitter. This study is based on the use of two scheduling algorithms to calculate the data in the MAC layer in order to provide maximum throughput. Moreover we propose a scheme to calculate the jitter between the various mobile users. The scheme performance is investigated through simulation. Priority Queuing gives better throughput compared to the Random Early Detection. Also jitter is minimized in priority queuing.

Further results on local stability of LRC-RED algorithm in Internet

This paper presents some further results on the local stability of a recently developed Internet congestion control scheme, namely the loss ratio and rate control random early detection (LRC-RED) algorithm. Necessary and sufficient stability conditions in terms of key tuning parameters are derived, which can provide further guidelines for control gain selection. The numerical simulations are given to illustrate the correctness of the theoretical analysis.

Performance Evaluation of AQM Techniques in PIM-DM Multicast Network for SRM Protocol

The focus of this work is to study the behavior of various queue management algorithms, including RED (Random Early Detection), RIO (RED IN/OUT), SRR, SFB (Stochastic Fair Blue) and BLUE. The performance metrics of the comparison are Throughput (Quantity of Service), end–to–end delay (Quality of Service) and drop of packets. The simulation is done using NS-2. In this paper we have illustrated the different behavior of RED, RIO, SFB, SRR and BLUE, which use the queue length as the indicator of the grimness of congestion. Thus SFB achieve significant better performance in terms of packet loss rates and throughput in the Network.

Game-theoretic analysis of Internet switching with selfish users

We consider the problem of Internet switching, where traffic is generated by selfish users. We study a packetized (TCP-like) traffic model, which is more accurate than the widely used fluid model. We assume that routers have First-In-First-Out (FIFO) buffers of bounded capacity managed by the drop-tail policy. The utility of each user depends on its goodput and the congestion level. Since selfish users try to maximize their own utility disregarding the system objectives, we study Nash equilibria that correspond to a steady state of the system. We quantify the degradation in the network performance called the price of anarchy resulting from such selfish behavior. We show that for a single bottleneck buffer, the price of anarchy is proportional to the number of users. Then we propose a simple modification of the Random Early Detection (RED) drop policy, which reduces the price of anarchy to a constant. We demonstrate that a Nash equilibrium can be reached if all users deploy TCP Vegas as their transport protocol under the drop-tail policy. We also consider some natural extensions of our model including the case of multiple Quality of Service (QoS) requirements, routing on parallel links and general networks with multiple bottlenecks.

Fuzzy-Logic Adaptive Queuing for a Heuristic TCP Performance in Mobile Wireless Networks

In this paper, we propose a new Fuzzy-Logic Adaptive Queuing controller (FLAQ) based on a classical Random Early Detection (RED) algorithm in wireless cellular network. The controller predicts dynamically the packet dropping rate and the corresponding average queue length. It relies on the average queue length at the base station router and the packet loss rate caused by the channel variations in mobile environment; assuming there is no buffer overflow due to the congestion. Using this model, a heuristic TCP performance can be estimated over a time-varying channel under different conditions of user’s mobility. The results show a significant improvement in TCP throughput performance when the user’s mobility is below 5 m/s; and becomes constant (i.e., close to i.i.d) beyond this speed especially at 5% of predefined packet error rate.

Service Violation Monitoring Model for Detecting and Tracing Bandwidth Abuse

Bandwidth abuse is a critical Internet service violation. However, its origins are difficult to detect and trace given similarities between abusive and normal traffic. So far, there is no capable and scalable mechanism to deal with bandwidth abuse. This paper proposes a distributed edge-to-edge model for monitoring service level agreement (SLA) violations and tracing abusive traffic to its origins. The mechanism of policing misbehaving user traffic at a single random early detection (RED) gateway is used in the distributed monitoring of SLA violations, including violations carried out through several gateways. Each RED gateway reports misbehaving users who have been sent notifications of traffic policing to an SLA monitoring unit. Misbehaving users are considered suspicious users and their consumed bandwidth shares are aggregated at every gateway to be compared with SLA-specified ratios. Bandwidth is abused when SLA-specified ratios are exceeded. By reporting bandwidth abuse, illegitimate users can be isolated from legitimate ones and source hosts of abusive traffic may be traced. Approximate simulation results show that the proposed model can detect any SLA violation and identify abusive users. In addition, the proposed model can trace user violations back to their source machines in real time.

Improving MANET performance by a hop‐aware and energy‐based buffer management scheme

ABSTRACTA hop‐aware and energy‐based buffer management scheme (HEB) is proposed in this paper. HEB can provide better quality of service to packets with real‐time requirements and improve MANET power efficiency. In our algorithm, the buffer is divided into real‐time and non‐real‐time partitions. We consider the number of hops passed, the power levels of the transmitting node, the predicted number of remaining hops, and waiting time in the buffer to determine packet transmission priority. In addition, specialized queue management and a probabilistic scheduling algorithm are proposed to decrease retransmissions caused by packet losses. Mathematical derivations of loss rates and end‐to‐end delays are also proposed. Coincidence between mathematical and simulation results is also shown. Finally, the HEB is compared with first in first out, random early detection, and hop‐aware buffering scheme. Simulation results show that the proposed algorithm reduces loss rates, power consumption, and end‐to‐end delays for real‐time traffic, considerably improving the efficiency of queue management in MANET. Copyright © 2012 John Wiley & Sons, Ltd.

Improving network congestion: A RED-based FuzzyPID approach

This research proposes a new active queue management method (or FPID) to improve network congestion, which integrates the random early detection (RED) method and fuzzy proportional integral derivative (FuzzyPID) approach. Fuzzy theory applied together with PID helps control the buffer queue within the target. This article provides the literature and theoretical background of network congestion problems, active queue management methods, automatic control systems, and fuzzy controllers. Following the discussion of the proposed FPID method and the experimental design, a simulation test is conducted and analyzed in comparison to the existing popular active queue management methods. The results prove the superiority of the proposed method.

NS Simulator for Beginners

NS-2 is an open-source discrete event network simulator which is widely used by both the research community as well as by the people involved in the standardization protocols of IETF. The goal of this book is twofold: on one hand to learn how to use the NS-2 simulator, and on the other hand, to become acquainted with and to understand the operation of some of the simulated objects using NS-2 simulations. The book is intended to help students, engineers or researchers who need not have much background in programming or who want to learn through simple examples how to analyse some simulated objects using NS-2. Simulations may differ from each other in many aspects: the applications, topologies, parameters of network objects (links, nodes) and protocols used, etc. The first chapter is a general introduction to the book, where the importance of NS-2 as a tool for a good comprehension of networks and protocols is stated. In the next chapters we present special topics as TCP, RED, etc., using NS-2 as a tool for better understanding the protocols. We provide in the appendices a review of Random Variables and Confidence Intervals, as well as a first sketch for using the new NS-3 simulator. Table of Contents: Introduction / NS-2 Simulator Preliminaries / How to work with trace files / Description and simulation of TCP/IP / Routing and network dynamics / RED: Random Early Discard / Differentiated Services / Mobile Networks and Wireless Local Area Networks / Classical queueing models / Tcl and C++ linkage

Nonconvex integer optimal robust impulsive control strategy for first-order piecewise finite precision nonlinear random early detection algorithm

There are two main contributions of this paper. First, this paper proposes a first-order piecewise finite precision nonlinear dynamical model for characterizing the average queue size of the random early detection (RED) algorithm. Second, this paper proposes a nonconvex integer optimal robust impulsive control strategy for stabilizing the average queue size. The objective of the control strategy is to determine the average queue size so that the average power of the impulsive control force is minimized subject to a constraint on the absolute difference between the actual average queue size and the theoretical average queue size at the equilibrium point. Computer numerical simulation results show that the proposed control strategy is effective and efficient for stabilizing the average queue size.

Adaptive active queue management controller for TCP communication networks using PSO-RBF models

Addressing performance degradations in end-to-end congestion control has been one of the most active research areas in the last decade. Active queue management (AQM) aims to improve the overall network throughput, while providing lower delay and reduce packet loss and improving network. The basic idea is to actively trigger packet dropping (or marking provided by explicit congestion notification (ECN)) before buffer overflow. Radial bias function (RBF)-based AQM controller is proposed in this paper. RBF controller is suitable as an AQM scheme to control congestion in TCP communication networks since it is nonlinear. Particle swarm optimization (PSO) algorithm is also employed to derive RBF parameters such that the integrated-absolute error (IAE) is minimized. Furthermore, in order to improve the robustness of RBF controller, an error-integral term is added to RBF equation. The results of the comparison with Drop Tail, adaptive random early detection (ARED), random exponential marking (REM), and proportional-integral (PI) controllers are presented. Integral-RBF has better performance not only in comparison with RBF but also with ARED, REM and PI controllers in the case of link utilization while packet loss rate is small.

Survey on Random Early Detection Mechanism and Its Variants

Active Queue Management (AQM) algorithms are an Implementing schemes, So that packets are transmitted with higher priority than others. Random Early Detection (RED) is the first active queue management algorithm proposed for deployment in TCP/IP networks. RED has some parameter tuning issues that need to be carefully addressed for it to give good performance under different network scenarios. Various algorithms come from RED such as Stabilized RED (SRED), Dynamic RED (DRED), Adaptive RED (ARED) and Flow RED (FRED) these algorithms control congestion by discarding packets with a load dependent probability whenever a queue in the network appear to be congested, this paper will introduced some features about RED and its variants.

Queue management for the heavy-tailed traffics

The purpose of this research is to design a new queue management algorithm effectively controlling the heavy-tailed traffics. Among active queue managements (AQM), random early detection (RED), has been widely used to improve the TCP throughput. The heavy-tailed traffic, however, generates the large fluctuation on the queue causing the degradation of fairness in terms of throughput and jitter performance. In this paper, we proposed the stable time RED (ST-RED) to improve the fairness of throughput and jitter performance. ST-RED enables to stabilise the calculation timing for average queue length leading to suppress the queue fluctuations. We also implemented the ST-RED mechanism on the ns-2 simulator. As results of simulation, we extracted the following features. Firstly, RED improves the throughput and reduces the overall load balance leading to the improvement of its fairness with all different αs of the Pareto distribution. Secondly, ST-RED keeps the same TCP throughput performance for each traffic wit...

Simulation Based Performance Evaluation of Queueing Disciplines for Multi-Class Traffic

Queuing is one of the very vital mechanisms in traffic management system. Each router in the network must implement some queuing discipline that governs how packets are buffered while waiting to be transmitted. Several queue scheduling disciplines have been designed to improve the quality of service and to avoid congestion for networked multimedia applications. In this paper, we evaluate the performance of four queueing disciplines (FIFO, PQ, WFQ and DWRR) that are widely deployed for multi-class traffic and analyze their performance using OPNET simulator and compare their relative performance based on queueing delay, packet received, packet drop rate, end-to-end delay and delay jitter with RED and WRED policies. Keywords - Deficit-Weighted Round Robin, Multi-Class Traffic, OPNET Simulation, Priority Queuing, Weighted-Fair Queuing. I. Introduction With the growth of internet during the last decade IP networks are expected to support not only typical services like ftp and email but also video streaming and voice applications. There are many network parameters for its performance evaluation that are required for different application A number of queueing disciplines have been proposed to achieve the required quality of service in today's network services. In this paper, we analyze the performance of a typical network topology under four different queueing disciplines which are widely deployed and compare their performance OPNET simulator (2). The queueing disciplines considered are: First- In-First-Out (FIFO), Priority Queueing (PQ), Weighted Fair queueing (WFQ) and Deficit Weighted Round Robin queueing (DWRR). We also scrutinize the effect of two dropping policies, random-early drop (RED) (3) and weighted random-early drop(WRED), on their performance. We then present the simulation results and evaluate their performance.