Congestion Avoidance Phase Research Articles

Methodical Improvement of Congestion Control Mechanism in Distinctive Data Transmission

Data transmission using protocols such as TCP (Transmission Control Protocol) between wireless and wired systems, is still include a concrete difficult. The congestion control appliance does not allow the flow of data to obtain a full bandwidth on present system acquaintances. To resolving this problematic, various protocols is hosted with a high performance. Consequently, this article improved congestion control algorithm and congestion window (cwnd) is suggested to increase TCP performance by growing the cycles number of the next cwnd to improving the number of sent packets. The suggested procedure uses a novel technique supported by the existing bandwidth of links to detecting the capacity of the network channel to develop a steady clocking mechanism in congestion avoidance phase. The effort provided in this article is based on Network Simulation (NS-2) to modeling the putative mechanism.

Improving the TCP Newreno Congestion Avoidance Algorithm on 5G Networks

Enhancing Transmission Control Protocol (TCP) performance is one of the key solutions for improving the performance of modern wireless communication networks. It is a highly dependable protocol for communication between network hosts based on an internet protocol (IP). It uses packet sequence numbering and acknowledgment (ACK) packets to ensure that data is recoverable in the event of problems like data loss, and corruption. Loss-based Congestion Control (CC) algorithms overreact and underperform in the presence of rapid channel oscillations, resulting in buffer bloat and significant delays. The goal of this paper is to develop an efficient congestion control mechanism for the new TCP agent Newreno over the fifth generation (5G) network, as well as to improve the increment and decrement strategy for adjusting the congestion window (cwnd) during the congestion avoidance phase, It also fast adapts to the current network requirements and adjusts the transmission rate accordingly. TCP enhancements can improve performance under dynamic traffic loads and over long product channels with high bandwidth. As a result, when such a TCP congestion control mechanism is improved, the network’s throughput increases, and low packet losses, and delay are reduced.

A Genetic Predictive Model Approach for Smart Traffic Prediction and Congestion Avoidance for Urban Transportation

With emerging population and transportation in today’s world, traffic has become a challenging issue to be addressed. Most of the metropolitan cities are facing various traffic-related issues. This poses the need for a smart traffic system, which could tackle the external environment and provide energy efficient transportation system. Intelligent transportation system (ITS) is required to support traffic management system in smart cities. The existing systems concentrate on the traffic prediction to yield better results. The work in this paper proposes a Smart Traffic Prediction and Congestion Avoidance System (s-TPCA) which helps in better identification of the traffic scenario that in turn helps in predicting and avoiding the congestion. The proposed work uses Poisson distribution for prediction of vehicle arrivals from recurring size. The framework comprises traffic identification, prediction, and congestion avoidance phases. The system checks for the fitness function to determine the traffic intensity and further use predictive analytics to determine the traffic level in future. This also integrates fuel consumption model to save time and energy. The proposed s-TPCA system outperforms the conventional systems in terms of delay and proves to conserve energy. The fuel conservation is observed to be 20% higher than the other existing systems.

FB-TCP: A 5G mmWave Friendly TCP for Urban Deployments

5G era opens a new horizon toward communication with new features and capabilities. The new mobile generation comes up with a multi-gigabit per second data rate along with its huge available bandwidths provided by millimeter-wave frequency bands. Dispensing a fully connected world throughout low latency is the supreme aim for 5G networks. However, attaining high-speed, reliable communication is challenging in the new generation, especially in scenarios with numerous obstacles such as the urban one. As the frequency rises, the signal's penetration power declines, which can mislead TCP in adjusting the sending rate because TCP cannot distinguish that a packet drop in a network is due to congestion or other shortcomings of the network such as blockage or random packet drops. This paper proposes a new TCP based on Fuzzy logic, which strives to prevent performance reduction in urban deployments. The Fuzzy rules are implemented in the congestion avoidance phase of the new protocol to adjust the sending rate intelligently and prevent blockage impacts. The ultimate aim of the protocol is to control the sending rate based on the current situation of the network so it can attain the highest possible performance. Moreover, it tries to reach its goal through low latency and keep the average sending rate as small as possible to restrain the buffer exhaustion. The extensive conducted simulations showed that the newly proposed protocol could attain higher performance compared to BBR, HighSpeed, Cubic, and NewReno in terms of throughput, RTT, and sending rate adjustment in the urban scenario.

Performance Analysis of TCP New Reno Over Satellite DVB-RCS2 Random Access Links

In this paper, the performance evaluation of TCP New Reno over satellite DVB-RCS2 links with random access is analyzed. Based on the satellite system consisting of a large number of source-destination TCP New Reno pairs, a Markov chain model for a TCP connection is conducted. According to the principles of TCP New Reno, two one-step transition probabilities for the value of congestion window in different data transmission phases (e.g. the slow start phase and congestion avoidance phase) are proposed. In order to analysis the throughput of a TCP connection, according to the packets lost events, three conditions (no packet lost, packets lost in the congestion avoidance phase, and packets lost in the slow start phase), are theoretically analyzed. We analytically derive the upper and lower throughput bounds, simulations and analysis are integrated together to indicate the effective ness and correctness of theoretical analysis. Moreover, we can clearly determine which factor plays role for the performance of TCP New Reno. The analysis not only includes the main algorithms of TCP protocol, but also is developed for general random access. Therefore, the Markov model and the theoretical analysis can be applied to many erasure channel, and the conclusions are extremely critical for the research of improving TCP performance over links with random access.

Comparative analysis of cumulative distribution function for TCP congestion window size and triple‐duplicate period

SummaryVarious version of Transmission Control Protocol (TCP) congestion window model are available in the literature. TCP congestion control is handled in two phases: (a) slow start and (b) congestion avoidance. This paper deals with congestion avoidance phase that is based on additive increase multiplicative decrease (AIMD) mechanism in which window size either increase by one or cuts to half of the previous window size. For distribution of window sizes, a model developed by Yan et al has been presented for two loss indications: (a) triple duplicate (TD) and (b) time‐outs (TOs) only while it does not deal with the window size limitation. It does not allow to cap over the TCP congestion window size if the buffer size is restricted to a fixed value though window size could not move beyond that. The unconstrained window size moves on in the presence of low loss probability. In this paper, we propose a model for the case where the window size is bounded by a maximum value that makes applicable to window size limitation as well. Further, the work has been extended to develop a new model that obtains a cumulative distribution function for TD periods (TDPs). The proposed model is validated on ns‐2, and we conclude that observed results for distribution function are very closed to our proposed model.

Modeling MPTCP Performance

Multi-path TCP (MPTCP) has been standardized by IETF and being used in practice. However, the MPTCP performance analysis has been paid less attention than algorithm improvement, such as coupled congestion control between subflows. The existing analytical models lack consideration of both slow start and congestion avoidance phases. In this letter, we perform a full analysis to derive the MPTCP performance by considering both the phases in the network with shared bottleneck so that we can calculate data transfer latency as well as throughput for a given size of data. Via direct code execution on top of the NS-3 simulation, we show that the proposed analysis captures data transfer latency under packet losses due to buffer overflow.

Performance evaluation of TCP-BIAD in high-speed, long-distance networks

In this paper, the performance of Binary Increase Adaptive Decrease (TCP-BIAD) congestion control algorithm in high-speed long-distance networks is evaluated. As its name implies, this TCP variant is a combination of an enhanced binary increase algorithm during the congestion avoidance phase with the adaptive decrease mechanism of TCP Westwood after a packet loss episode. We also propose a mathematical analysis of the TCP-BIAD paradigm to study the steady-state throughput provided by TCP-BIAD and investigate the intra-protocol friendliness between TCP-BIAD and Additive Increase/Multiplicative Decrease algorithms. Our analysis shows that TCP-BIAD algorithm is exponentially stable, while maintaining an adequately fair and friendly behavior with respect to co-existing TCP-Reno flows. Finally, our results are validated with respect to other TCP variants such as BIC-TCP, CUBIC, HighSpeed TCP, HTCP, Hybla and TCP-Reno by means of computer simulations in networks with large bandwidth-delay products and low sensitivity to RTT values.

Energy Efficient Congestion Control for Multipath TCP in Heterogeneous Networks

In this paper, we propose a receiver energy efficient congestion control algorithm based on multipath transmission control protocol (MPTCP) to enable the battery powered mobile devices receive more data than MPTCP with the same energy consumption. First, based on the receiver energy consumption model of wireless interface, a constrained optimization problem to maximize energy efficiency is formed. With genetic algorithm, a rate distribution vector is obtained as a near-optimal solution. Second, we adjust the congestion windows based on the acquired vector to schedule packets over each path directly. Jointly considering energy efficiency, round trip time and path loss rate, a novel congestion control algorithm is proposed to adjust the increment of congestion window when an acknowledgement is received in the congestion avoidance phase. The energy efficiency term is obtained by extending the energy efficient rate distribution vector into the window-based congestion control algorithm via fluid model. The simulation results demonstrate that the proposed algorithm shifts part of traffic from the higher energy consumption paths to the lower ones. It improves throughput greatly and achieves higher energy efficiency, almost twice the size of MPTCP.

Dynamic TCP-Vegas based on cuckoo search for efficient congestion control for MANET

In the internet congestion control, transmission control protocol (TCP)-Vegas is a source algorithm that provides better performance. However, it has two main issues: first one is rerouting and unable to identify updation of round-trip time (RTT) when changes occurred in the network, these two problems leads to affects the performance of Vegas. These drawbacks persist mostly in the Vegas estimation process of the propagation delay, i.e. BaseRTT. In this paper, we proposed a novel algorithm that uses the cuckoo search optimisation algorithm for selecting the optimal value of BaseRTT. Also, our proposed algorithm has dynamically considered slow start algorithm based on the estimation in real time, the available bandwidth and adjust decrease/ increase rate in congestion avoidance phase for a particular network environment. Simulation results have shown that our proposed algorithm can effectively avoid packet losses and attain the maximum throughput when compared with existing algorithms.

Finishing the tiny flows quickly for common data centre services

Meeting the deadline requirement for the application flow is always a challenge in data centre. Aiming at this problem, many transmission control protocol (TCP) variants are proposed and most of them focus on improving the congestion avoidance phase while rarely considering the slow-start. This paper presents an improved TCP slow-start mechanism, which uses large initial windows (LIW) to help more flows to be finished before their deadlines and does not increase the network congestion meanwhile. The simulation results show that LIW can greatly enhance the meeting deadline ratio of flows involved in web searching and data mining application services which are common in data centres. Moreover, LIW can be easily deployed with rarely modifying the TCP stack.

Finishing the tiny flows quickly for common data centre services

Meeting the deadline requirement for the application flow is always a challenge in data centre. Aiming at this problem, many transmission control protocol (TCP) variants are proposed and most of them focus on improving the congestion avoidance phase while rarely considering the slow-start. This paper presents an improved TCP slow-start mechanism, which uses large initial windows (LIW) to help more flows to be finished before their deadlines and does not increase the network congestion meanwhile. The simulation results show that LIW can greatly enhance the meeting deadline ratio of flows involved in web searching and data mining application services which are common in data centres. Moreover, LIW can be easily deployed with rarely modifying the TCP stack.

Improvement of SCTP congestion control in the LTE-A network

Long Term Evolution-Advanced (LTE-A) is the fourth-generation wireless communication of mobile technology. LTE-A offers a scalable coverage as it possesses efficient throughput and ubiquitous connectivity. The congestion control of the LTE-A transport layer negatively influences the overall performance of the throughput. Moreover, the existing slow-start and congestion avoidance mechanisms helps to reduce the LTE-A performance. Thus, this paper improves the congestion control mechanism by incorporating the Stream Control Transmission Protocol (SCTP) in LTE-A. Specifically, the slow-start and congestion avoidance phases will be improved. The proposed mechanism, called ENH-SCTP, reduces the time duration, towards reaching a threshold, by ranking the congestion window, throughput, queue size and packet loss as performance metrics. The ranking can be achieved by adding a value which selection is based on a multi-criteria problem. Concretely we used the multi-criteria decision-making (MCDM) technique, especially the utilization of the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The simulation results show that the proposed SCTP in LTE-A performs better than the conventional SCTP. As a consequence, the congestion window, throughput, queue size and packet loss are significantly improved.

An Improved TCP Congestion Control Algorithm in High Speed Satellite Links

The throughput of traditional TCP degrades drastically in high speed satellite links, where the characteristics of long round trip time (RTT) and high bit error rate (BER) happen together. Two typical improved algorithms, Hybla and Westwood, are designed to solve the problems of long RTT and high BER respectively. TCP-HW which combines the advantages of Hybla and Westwood is proposed in this paper, on the basis of consideration of both long RTT and high BER. At slow start and congestion avoidance phase, TCP-HW adopts a radical congestion window (cwnd) growth policy to eliminate the low data transmission rate bring by long RTT as Hybla does. At fast retransmit and fast recover phase, TCP-HW updates the cwnd according to the estimated available bandwidth in Westwood to avoid the frequently unnecessary reduction of cwnd due to high BER. There, the cwnd can be kept large enough to achieve high throughput. Simulation results in NS2 indicate that the change of RTT and packet error rate (PER) has little impact on TCP-HW and the bandwidth utilization of TCP-HW can reach more than fifty percent in the 1Gbps GEO satellite link with 500ms RTT and 0.001 PER. In addition, TCP-HW still have good fairness.

Vegas-f: Adaptive Growth Rate of Slow Start for TCP Vegas in Large Bandwidth-Delay Network

TCP Vegas has the problem that it stops slow start too early, and it is more obvious in the large delay-bandwidth network. This phenomenon can cause a very long linear growth after entering congestion avoidance phase, and it will reduce the transmission efficiency. This paper analyzes that the reasons for this phenomenon is due to the exponential growth of slow start itself, then puts forward a dynamic growth algorithms of slow start, we call it Vegas-f. Improved algorithms can dynamically adjust the growth rate of slow start, so as to improve the transmission efficiency and competitiveness in mixing network. Simulation results show that the improved algorithm has completely solved the problem and the performance is improved significantly.

Adaptive Logarithmic Increase Congestion Control Algorithm for Satellite Networks

This paper presents a new algorithm called the adaptive logarithmic increase and adaptive decrease algorithm (A-LIAD), which mainly addresses the Round-Trip Time (RTT) fairness problem in satellite networks with a very high propagation delay as an alternative to the current TCP congestion control algorithm. We defined a new increasing function in the fashion of a logarithm depending on the increasing factor α, which is different from the other logarithmic increase algorithm adopting a fixed value of α = 2 leading to a binary increase. In A-LIAD, the α value is derived in the RTT function through the analysis. With the modification of the increasing function applied for the congestion avoidance phase, a hybrid scheme is also presented for the slow start phase. From this hybrid scheme, we can avoid an overshooting problem during a slow start phase even without a SACK option. To verify the feasibility of the algorithm for deployment in a high-speed and long-distance network, several aspects are evaluated through an NS-2 simulation. We performed simulations for intra- and inter-fairness as well as utilization in different conditions of varying RTT, bandwidth, and PER. From these simulations, we showed that although A-LIAD is not the best in all aspects, it provides a competitive performance in almost all aspects, especially in the start-up and packet loss impact, and thus can be an alternative TCP congestion control algorithm for high BDP networks including a satellite network.

광대역 무선 네트워크에서 효율적인 멀티미디어 전송을 위한 혼잡 제어 기법

TCP does not ensure the bandwidth and delay bound required for multimedia streaming services in broadband wireless network environments. In this paper, we propose a new congestion control scheme for efficient multimedia transmission, called COLO TCP (Concave Increase Slow Start Logarithmic Increase Congestion Avoidance TCP). The COLO TCP prevents the burst packet loss by applying the concave increase algorithm in slow start phase. In the congestion avoidance phase, COLO TCP uses the logarithmic increase algorithm that quickly recovers congestion window after packet loss. To highly utilize network bandwidth and reduce packet loss ratio, COLO TCP uses additive increase algorithm and adaptive decrease algorithm . Through simulation results, we prove that our COLO TCP is more robust for random loss. It is also possible for efficient multimedia transmission.

Analytical modeling of Transmission Control Protocol NewReno using Generalized Stochastic Petri Nets

SUMMARYThis paper presents a novel analytical model of Transmission Control Protocol (TCP) using a generalized stochastic Petri net (GSPN). Extensive simulation work has been done for the performance evaluation of TCP NewReno protocol. In view of the limitations of the simulation technique, we present an analytical approach using GSPN. A GSPN is a useful mathematical tool that solves continuous time Markov chains for complex systems and evaluates the stationary behavior. In this paper, we analyze the slow‐but‐steady variant of TCP NewReno. The model captures the behavioral aspects of the slow start and the congestion avoidance phase together with the fast retransmit and recovery capabilities of TCP NewReno. Performance metrics such as throughput, goodput, and task completion time of the system are obtained. The effect of variation in the model parameters on the performance is studied. The results are validated using the network simulator, and their accuracy is verified by evaluating the confidence interval. The performance of the proposed model is compared with that of TCP Reno. The performance of the proposed model is also compared with one of the previous models. The numerical illustrations and comparison of the proposed technique with simulation validates the accuracy, efficiency, and competence of the GSPN technique. While GSPN modeling for TCP is investigated in depth for the TCP NewReno and TCP Reno variant in this paper, other protocols could be also analyzed similarly. Copyright © 2013 John Wiley & Sons, Ltd.

TCP congestion avoidance algorithm based on adaptive congestion window

Concerning the unsmooth growth of congestion window at congestion avoidance phase of TCP Reno,the traditional AIMD algorithm was researched and an improved congestion avoidance algorithm was proposed: a logarithmic function based on the growth of congestion window was adopted.In this new algorithm,additive factor is usually increased quickly when the network is doing well and less so when network situation is getting to congestion.The mathematical analysis shows the feasibility of the new algorithm,and its throughput,fairness and friendliness were evaluated by NS simulation.The simulation results show the effectiveness of the algorithm.

Performance Enhancement of DCCP TCP-like over Long Delay Link Networks

The performance of DCCP TCP-like degrades significantly over long delay link networks. Despite the TCP-like congestion control mechanism follows the TCP SACK, the performance is really affected by the congestion window growth algorithms as employed by Jacobson based TCP variants. In this paper, all the experiments are done using Network Simulator ns-2, and we manipulated the congestion window size drop during congestion avoidance phase to enhance the performance of DCCP TCP-like over long delay link networks. Instead of halving the current congestion window when congestion events are detected, the reduction of current congestion window drop has been shown to improve the DCCP TCP-like throughput with minimal drop packet percentage.