RED Algorithm Research Articles

A Kind of Improved RED Algorithm of WSN Oriented to Self-Similar Traffic

Active queue management algorithm works at network routing node. It notifies terminal system control transmission rate in advance with discard or mark packet before buffer queue overflows, so as to avoid congestion. Aiming at characteristics of wireless sensor network (WSN) and based on introduction of traditional RED algorithm, the paper introduced H parameter to represent traffic similarity to original linear relationship between packet loss probability and average queue length to form the non-linear relationship related to self-similarity. Then a kind of improved RED algorithm of WSN oriented to self-similar traffic was proposed. The detail implementation flow was also provided. Simulation based on OPNET shows that the improved RED is superior to traditional RED algorithm in steady performance.

An Improved Adaptive Active Queue Management Algorithm Based on Nonlinear Smoothing

According to analyzing the principle and limitations of RED and its improved algorithms, an improved adaptive RED congestion control mechanism is proposed in this paper, which imposes nonlinear smooth for packet loss rate function of RED algorithm by using the membership function of the ascend demi-cauchy of fuzzy distribution. The speed of growth of packet loss rate is relatively slow near the minimum threshold, while near the maximum threshold the speed of growth of packet loss rate is relatively faster. ThePmax will be dynamically adjusted by the length of average queue and the target for adapting the changing of network environment. NS simulation shows that this algorithm has been significantly improved for packet loss rate, throughput and other performance.

Robustness of RED in Mitigating LDoS Attack

The Random Early Detection algorithm is widely used in the queue management mechanism of the router. We find that the parameters of the RED algorithm have a significant influence on the defense performance of the random early detection algorithm and discuss the robust of the algorithm in mitigating Low-rate Denial-of-Service attack in details. Simulation results show that the defense performance can be effectively improved by adjusting the parameters of Q min andQ max . Some suggestions are given for mitigating the LDoS attack at the end of this paper.

Active Network Based Queue Management for Providing QoS Using IXP 2400 Network Processor

The objective of this paper is to implement the Active Network based Active Queue Management Technique for providing Quality of Service (QoS) using Network Processor (NP) based router to enhance multimedia applications. The performance is evaluated using Intel IXP2400 NP Simulator. The results demonstrate that, Active Network based Active Queue Management has better performance than RED algorithm and is well suited to achieve high speed packet classification to support multimedia applications with minimum delay and Queue loss. Using simulation, we show that the proposed system can provide assurance for prioritized flows with improved network utilization where bandwidth is shared among the flows according to the levels of priority. We first analyze the feasibility and optimality of the load distribution schemes and then present separate solutions for non-delaysensitive streams and delay-sensitive streams. Rigorous simulations and experiments have been carried out to evaluate the performance.

Linear stability and Hopf bifurcation in an exponential RED algorithm model

We consider a novel congestion control model, i.e., the exponential RED algorithm with a single link and single source. Using the gain parameter of the system instead of the delay as the bifurcation parameter, the linear stability and Hopf bifurcation are investigated, and the stability and direction of the Hopf bifurcation are determined by employing the normal form method and the center manifold reduction. Numerical simulations are carried out to illustrate our theoretical results.

Linear stability and Hopf bifurcation analysis for exponential RED algorithm with heterogeneous delays

In this paper, the exponential RED algorithm with heterogeneous delays is considered. Local stability of the equilibrium solution of this algorithm is investigated based on analyzing the corresponding transcendental characteristic equation. Some general stability criteria involving the delays and the system parameters are derived by using generalized Nyquist criteria. In particular, using one of the delays as the bifurcation parameter, when the delays exceed a critical value, the exponential RED system undergoes a supercritical Hopf bifurcation. The explicit formulas determining the stability and the direction of periodic solutions bifurcating from the equilibrium are obtained by applying Hassard et al’s approaches. Finally, some numerical simulations are performed to verify the theoretical results.

A Hybrid Random Early Detection Algorithm for Improving End-to-End Congestion Control in TCP/IP Networks

The successful operation of the present Internet depends mainly upon TCP/IP which employs end-to-end congestion
 control mechanisms built in the end hosts. In order to further enhance this paradigm of end-to-end control the
 Random Early Detection algorithm (RED) has been proposed, which starts to mark or drop packets at the onset of congestion. 
 The paper addresses issues related to the choice of queue length 
 indication parameters for packet marking/dropping decisions 
 in RED-type algorithms under varying traffic conditions. Two
 modifications to RED are proposed: (i) use of both instantaneous queue size and its Exponential Weighted Moving Average
 (EWMA) for packet marking/dropping and (ii) reducing the effect of the EWMA queue size value when the queue size is less than 
 $min_{th}$ for a certain number of consecutive packet arrivals. 
 
 The newly developed Hybrid RED algorithm can effectively improve the performance of TCP/IP based networks while working in a control loop formed by either dropping or marking of packets during congestion epochs. New guidelines are developed for better marking/dropping of packets to achieve a faster response of RED-type algorithms. The hybrid RED algorithm has been tested using ns-2 simulations, which show better utilization of network bandwidth and a lower packet loss rate.

New active queue management algorithm

A new Active Queue Management(AQM)algorithm based on the Misra's TCP windows stochastic differential equation was proposed.With the restriction on the bound sizes of TCP windows,the transfer function of the new AQM model was obtained by using local linearization technique,and then this transfer function was taken as the controlled object,the differences between the output of the transfer function and the ideal queue were controlled by a Proportional Integral Differential(PID)controller.The experimental simulation results show that the overall performance of the new algorithm is better than RED and ARED algorithm.

Necessary and sufficient conditions for Hopf bifurcation in exponential RED algorithm with communication delay

In this paper, we investigate a novel congestion control algorithm, i.e., exponential RED algorithm, with communication delay. We derive some necessary and sufficient conditions ensuring Hopf bifurcation to occur for this model. By choosing the delay as a bifurcation parameter, we demonstrated that Hopf bifurcation would occur when the delay exceeds a critical value. A formula for determining the bifurcation direction and stability of bifurcation periodic solutions is given by applying the normal form theory and the center manifold theorem. Some numerical simulations for justifying the theoretical results are also provided.

Stability and Hopf bifurcation analysis in a novel congestion control model with communication delay

In this paper, we investigated Hopf bifurcation by analyzing the distributed ranges of eigenvalues of characteristic linearized equation. Using communication delay as the bifurcation parameter, linear stability criteria dependent on communication delay have also been derived, and, furthermore, the direction of Hopf bifurcation as well as stability of periodic solution for the exponential RED algorithm with communication delay is studied. We find that the Hopf bifurcation occurs when the communication delay passes a sequence of critical values. The stability and direction of the Hopf bifurcation are determined by applying the normal form theory and the center manifold theorem. Finally, a numerical simulation is presented to verify the theoretical results.

Cross‐layer protocols for satellite communication networks: part I

Cross‐layer protocols for satellite communication networks: part I

Congestion due to Rate Variations in cdma2000 Data Networks

In order to support high data rate requirements and effectively manage the scarce wireless resources, additional bandwidth channels are allocated and taken away from mobile stations in 3G wireless data networks quite frequently. A TCP sender connected to the mobile, on seeing ACKs coming at a faster pace after additional bandwidth allocation, turns overtly optimistic and injects data into the network at a rate that might be excessive for an intermediate router, thereby leading to loss of multiple packets and subsequent prolonged recovery and periods of underutilization. In this work, we characterize this problem using an analytical model for losses based on continuous flow approximation as well as an extensive simulation setup. We also illustrate how bandwidth oscillations create more severe congestion than an increase in number of users to the extent that even RED algorithm is unable to check the sharp growth of queues. As a result, multiple packets are lost in a droptail fashion. We further demonstrate the dependence of congestion due to bandwidth allocation on the time during which mobiles' rates are increased and observe the degradation in performance for typical load scenarios. We also try to identify the boundary for stable operation of RED and finally present some possible methods for improving the performance.

Congestion Control for Mixed TCP and UDP Traffic

In this letter, we propose a protocol sensitive random early detection algorithm for active queue management to improve fairness between TCP and UDP flows and to reduce delay time with small overheads. The algorithm classifies the packets into responsive and unresponsive flows, and applies the RED algorithm individually to each classified group. Using ns-2 simulations, we showed the effectiveness of the proposed PSRED algorithm compared with several well-known AQM schemes, such as RED and RED-PD algorithms.

Using Markov chains for modelling networks

The paper contains the review and the discussion on modelling communication networks with the use of queuing models and Markov chains. It shows how to take into account various characteristics of real systems - like some control mechanisms and the traffic self-similarity. There are presented two mechanisms modelled with Markov chains: the RED algorithm in TCP/IP and a self-similar traffic shaping.

A simulation study of the Adaptive RIO (A-RIO) queue management algorithm

Active queue management (AQM) algorithms are useful not only for congestion avoidance purposes, but also for the differentiated forwarding of packets, as is done in the DiffServ architecture. It is well known that correctly setting the parameters of an AQM algorithm may prove difficult and error-prone. Besides, many studies have shown that the performance of AQM mechanisms is very sensitive to network conditions. In this paper we present a detailed simulation study of an Adaptive RIO (A-RIO) AQM algorithm which addresses both of these problems. A-RIO, first introduced by Orozco and Ros (2003), draws directly from the original RIO proposal of Clark and Fang (1998) and the Adaptive RED (A-RED) algorithm described by Floyd et al. (2001). Our results, based on ns-2 simulations, illustrate how A-RIO improves over RIO in terms of stabilizing the queue occupation (and, hence, queuing delay), while maintaining a high throughput and a good protection of high-priority packets; A-RIO could then be used for building controlled-delay, AF-based services. These results also provide some engineering rules that may be applied to improve the behaviour of the classical, non-adaptive RIO.

Design a congestion controller based on sliding mode variable structure control

As an effective mechanism acting on the intermediate nodes to support end-to-end congestion control, Active Queue Management (AQM) takes a trade-off between link utilization and delay experienced by data packets. Most existing AQM algorithms are heuristic, and lack a systematic and theoretical design and analysis approach. From the viewpoint of control theory, the AQM system can be regarded as a typical regulating system. Although the PI controller for AQM outperforms the RED algorithm, the mismatches in a simplified TCP flow model inevitably degrade the performance of controller designed using classical control theory. In this paper, a robust controller for AQM is developed based on Sliding Mode Variable Structure Control (SMVS). Because it is insensitive to noise and variance of parameters, it is very suitable for time-varying network systems. The principles and design of the SMVS controller are presented in detail. The integrated performance is evaluated using ns simulations. The results show that the SMVS is responsive and robust against disturbance. At the same time, a complete comparison between SMVS controller and PI controller is made. The conclusion is that both transient and steady performance of the SMVS controller is superior to those of PI controller, thus the SMVS controller can readily achieve to the AQM objectives.

A study of a high speed packet scheduling method for achieving fairness among TCP connections

In this paper, we first investigate the fairness between TCP Reno and TCP Vegas by focusing on the situation where Reno and Vegas connections share the bottleneck link. From the analysis and the simulation results, we find that the performance of TCP Vegas is much smaller than that of TCP Reno as opposed to an expectation on TCP Vegas. The RED algorithm improves the fairness to some degree, but there still be an inevitable trade‐off between fairness and throughput. Accordingly, we propose a ZL‐RED (Zombie Listed RED) algorithm, which enhances the RED algorithm to provide fair service for many flows at the bottleneck router. ZL‐RED uses the Zombie List, which has been originally proposed by SRED, to detect mis‐behaving flows which send packets at higher rate than others. Then, ZL‐RED sets higher packet discarding probabilities for those mis‐behaving flows. We evaluate an effectiveness of ZL‐RED by simulation experiments, and show that ZL‐RED can actually improve fairness among TCP connections.

Design of a fuzzy controller for active queue management

As an effective mechanism acting on the intermediate nodes to support end-to-end congestion control, active queue management (AQM) takes a trade-off between link utilization and delay experienced by data packets. From the point of view of the control theory, it is rational to regard AQM as a typical regulating system. Although proportional integral (PI) controller for AQM outperforms traditional RED algorithm, the mismatches in simplified TCP flow model inevitably degrades the performance because the design of PI controller is heavily dependent of the accuracy of the plant, such as, for small buffer the system tends to perform poorly. In this paper, the fuzzy logic controller (FLC) for AQM is designed based on the fuzzy logical control. Its superiority is independent of the model of the plant, which is very suitable to the high variability and uncertainty networks. We present the guidelines and highlights to design the parameters of the FLC. We then compare its performance with the PI controller through simulations, and investigate the impact of the network configuration and operating parameters on the stability and responsibility. The results show that the FLC is rather robust against the noise and disturbance caused by the round-trip time, the link capacity, the number of the active flows and the non-responsive UDP flows, etc., which badly degrade the performance of the PI controller. The transient response and tracking capability of the FLC is superior to that of the PI controller, which is beneficial to achieve the goals of AQM scheme.

Fluid-based analysis of a network of AQM routers supporting TCP flows with an application to RED

In this paper we use jump process driven Stochastic Differential Equations to model the interactions of a set of TCP flows and Active Queue Management routers in a network setting. We show how the SDEs can be transformed into a set of Ordinary Differential Equations which can be easily solved numerically. Our solution methodology scales well to a large number of flows. As an application, we model and solve a system where RED is the AQM policy. Our results show excellent agreement with those of similar networks simulated using the well known ns simulator. Our model enables us to get an in-depth understanding of the RED algorithm. Using the tools developed in this paper, we present a critical analysis of the RED algorithm. We explain the role played by the RED configuration parameters on the behavior of the algorithm in a network. We point out a flaw in the RED averaging mechanism which we believe is a cause of tuning problems for RED. We believe this modeling/solution methodology has a great potential in analyzing and understanding various network congestion control algorithms.