Improve Transmission Control Protocol Performance Research Articles

Enhanced Congestion Control Mechanism to Improving TCP Performance over Heterogeneous Wired-Cum-Wireless Environments

The proposed idea in this paper based on identifying an optimum congestion window (cwnd) of Transmission Control Protocol (TCP) the sender side. The proposed mechanism includes a strategy to keeping the cwnd in fixed level to a point that is the reasonable portion in the link, and then reformed substantially since the occasion of the control of the magnitude of the last cwnd level. At this time, the TCP cwnd is estimated conferring to the environment of new situation. The suggested technique is mainly operative on wireless channels, that are have an fundamentally high packet drop rate, than the enhanced TCP cwnd being self-determining of packet drop but keeping the transmitted packet rate on the same level

TCP-LoRaD: A Loss Recovery and Differentiation Algorithm for Improving TCP Performance over MANETs in Noisy Channels

Mobile Ad hoc Networks (MANETs) are becoming popular technologies because they offer flexibility in setting up anytime and anywhere, and provide communication support on the go. This communication requires the use of Transmission Control Protocol (TCP) which is not originally designed for use in MANET environments; therefore, it raises serious performance issues. To overcome the deficiency of the original TCP, several modifications have been proposed and reported in the networking literature. TCP-WELCOME (Wireless Environment, Link losses, and Congestion packet loss ModEls) is one of the better TCP variants suitable for MANETs. However, it has been found that this protocol has problems with packet losses because of network congestion as it adopts the original congestion control mechanism of TCP New Reno. We also found that TCP-WELCOME does not perform well in noisy channel conditions in wireless environments. In this paper, we propose a novel loss recovery and differentiation algorithm (called TCP-LoRaD) to overcome the above-mentioned TCP problems. We validate the performance of TCP-LoRaD through an extensive simulation setup using Riverbed Modeler (formerly OPNET). Results obtained show that the proposed TCP-LoRaD offers up to 20% higher throughput and about 15% lower end-to-end delays than the TCP-WELCOME in a noisy channel under medium to high traffic loads.

Analysis of Transmission Control Protocol Incast over Large-scale HPC Clusters

The lifecycle of large-scale applications executing on High-Performance Computing (HPC) clusters involves massive use of transmission control protocol (TCP) while performing orchestration for job completion on multiple compute resources. As the HPC clusters involve large local area network communication for distributing jobs over compute and data nodes, the core network fabric in cluster architecture faces heavy workloads of TCP sessions; causing more than average packet drop events. This results in the poor TCP throughput; thus reducing the overall performance indices of the cluster. In this article, we have analyzed the TCP behavior at nominal, average, and heavy transmission load in a cluster environment for assessing various alternatives to solve the problem. We have also analyzed the cumulative queuing behavior of multiple TCP sessions at the contention switch and used a fine-grained configuration at the network fabric to improve the TCP performance. The simulation results show that the smaller set of data flow suffers a significant throughput collapse. The performance of TCP variants tested indicates that the congestion control mechanism of these protocols plays a significant role in performance degradation and needs a scalable solution to improve TCP performance indices. In this paper, different versions of TCP are employed for an HPC compute cluster and data storage to cater to the TCP Incast problem and simple solutions are presented. It has been observed that none of the classical, as well as newer TCP variants, perform consistently under heavy fan-in workload but a better queue management system at the network fabric greatly simplifies the problem and improves the cluster performance.

U-NewReno transmission control protocol to improve TCP performance in Underwater Wireless Sensors Networks

Advances in the different fields of application on Underwater Wireless Sensor Networks (UWSNs) makes this environment more attractive for researchers and industry. Communication in this environment faces exceptional challenges, since its data transmission is experiencing a limitation in the use of bandwidth, the presence of surrounding noise and also the long delays of acoustic propagation. It is of great benefit to design an adaptive transmission control protocol (TCP) for the underwater environment. In this work, we propose U-New Reno a transmission control protocol suitable for the marine environment wherein we consider both the adaptation of the maximum size of the congestion window and the expiry of the round-trip time (RTT). U-New Reno can achieve a very significant improvement concerning the retransmission rate of the packets and the evolution of the number of packets delivered. The performances of both metrics are closely observed during the comparison of simulation results between the standard New Reno and our proposed U-New Reno.

TCP-CLD: Cross-Layer Design for Improving TCP Performance Over Cognitive Radio Networks

Due to the development and evolution in Cognitive Radio Networks (CRNs), the performance of Transmission Control Protocol (TCP) over CRN has become a crucial factor. TCP ensures the reliable end-to-end delivery of data, which is very important for the quality of service (QoS) requirements. TCP performance is severely affected by channel switching and channel availability in CRNs. The frequent occurrence of such events is due to CRNs nature which unnecessarily reduces the transmission rate which results in degrading the overall performance. In this paper, the authors investigate the limitations of using TCP NewReno (i.e., standard TCP) over CRNs, and further propose a cross-layer-design protocol based on an interaction between transport layer and lower layers to improve TCP performance over CRNs. The design is called Cross-Layer Design for TCP (TCP-CLD). It primarily aims at improving the TCP performance over CRNs via controlling and adapting a few selected TCP parameters. Specifically, the authors propose freezing the data transmission and re-transmission timeout (RTO) of TCP during the time of channel switching and channel unavailability. In addition, the authors update the size of congestion window (cwnd) of TCP based on the bandwidth and buffer size of relay nodes. Moreover, in the case of channel switching, the authors update the Round Trip Time (RTT) of TCP based on the new route delay. Simulation experiments have been conducted using ns-2 network simulator tool whereas results show that the proposed design achieves a significant performance improvement compared with the standard TCP NewReno protocol and the other known protocol, namely, TCP-CRAHN.

On implementation of DCTCP on three-tier and fat-tree data center network topologies.

A data center is a facility for housing computational and storage systems interconnected through a communication network called data center network (DCN). Due to a tremendous growth in the computational power, storage capacity and the number of inter-connected servers, the DCN faces challenges concerning efficiency, reliability and scalability. Although transmission control protocol (TCP) is a time-tested transport protocol in the Internet, DCN challenges such as inadequate buffer space in switches and bandwidth limitations have prompted the researchers to propose techniques to improve TCP performance or design new transport protocols for DCN. Data center TCP (DCTCP) emerge as one of the most promising solutions in this domain which employs the explicit congestion notification feature of TCP to enhance the TCP congestion control algorithm. While DCTCP has been analyzed for two-tier tree-based DCN topology for traffic between servers in the same rack which is common in cloud applications, it remains oblivious to the traffic patterns common in university and private enterprise networks which traverse the complete network interconnect spanning upper tier layers. We also recognize that DCTCP performance cannot remain unaffected by the underlying DCN architecture hence there is a need to test and compare DCTCP performance when implemented over diverse DCN architectures. Some of the most notable DCN architectures are the legacy three-tier, fat-tree, BCube, DCell, VL2, and CamCube. In this research, we simulate the two switch-centric DCN architectures; the widely deployed legacy three-tier architecture and the promising fat-tree architecture using network simulator and analyze the performance of DCTCP in terms of throughput and delay for realistic traffic patterns. We also examine how DCTCP prevents incast and outcast congestion when realistic DCN traffic patterns are employed in above mentioned topologies. Our results show that the underlying DCN architecture significantly impacts DCTCP performance. We find that DCTCP gives optimal performance in fat-tree topology and is most suitable for large networks.

Improving TCP Performance in Wireless Networks by Detection and Avoidance of Spurious Retransmission Timeouts

Transmission Control Protocol (TCP) is a connection oriented, reliable delivery, transport layer protocol. The performance of TCP is degraded when it is used in wireless networks. This is mainly because of the basic assumption of TCP that any packet loss is an indication of congestion, which is not true in wireless links. The TCP performance in wireless network can be improved by differentiating the wireless losses from the congestion losses. Various Loss Differentiation Algorithms (LDAs) are used to identify whether the packet losses are due to congestion or due to wireless links. The accuracy of wireless loss discrimination and the accuracy of congestion loss discrimination have a trade-off relationship based on their own threshold. The detection information of LDA alone is not sufficient to improve the performance of TCP due to presence of Spurious Retransmission Timeouts (SRTO). In this paper, a novel cross-layer approach, TCP-DDA (TCPDetection, Differentiation and Avoidance) is proposed, wherein the packet losses are differentiated using cross-layer based LDA, SRTO is detected and steps are taken to avoid the SRTO. A new TCP mechanism that is capable of detecting and differentiating the loss of retransmitted packets is also proposed, thereby enhancing the performance of TCP over wireless networks. The work is evaluated using simulation, and the performance improvement is observed by comparing with the existing TCP NewReno.

Cross Layer Techniques used for Improving TCP Performance in Wireless Networks: A Proposed Technique

Transmission Control Protocol (TCP) running in the Transport Layer of layered architecture models like OSI, has been struggling with poor performance in wireless networks. Various probable solutions have been established by researchers worldwide. One branch of solutions uses the Cross Layer Design for improving TCP performance. Cross Layer Design violates the layered architecture norms of strictly discrete layers, and is used to improve TCP performance in wireless technology. In this paper, we talk about two cross layer techniques that have been established by researchers over past few years, employed to improve TCP performance. We compare, contrast and judge these techniques and propose our own technique for the same.

Acknowledgment Time Delay Approach to Optimize TCP Performance in Hybrid Networked Systems

Transmission Control Protocol (TCP) is connection oriented transport protocol used on IP in wireless medium and it insists lossless data transmission in proper order. When TCP is used as a transmission protocol where physical layer is wireless medium, results high packet reordering due to bursty traffic and drastic variation in quality of service with respect to time. By sharing the same path for data and acknowledgement increases the traffic and collision, resulting in reduced throughput. In order to improve QoS this paper proposes a solution “Improved Delay the Duplicate Acknowledgement” (IDDA). This reduces traffic and spurious retransmissions, thereby improving TCP performance.

Improving TCP Performance based on Fuzzy-Logic for Mobile Ad hoc Networks

Transmission Control Protocol (TCP) is designed for wired networks and the sender assumes that packet loss is an indicator of network congestion. However, this assumption may not apply to Mobile Ad hoc Networks (MANETs). Numerous transmission control protocols have been proposed in the literature to address the problem of congestion in MANETs. Their performance is highly dependent on networks conditions, probe and explicit notification messages. This paper proposed a fuzzy logic based inference system based on the factors of expected throughput and actual throughput to dynamically adjust the congestion window size to improve the performance of TCP in MANETs. Fuzzy inference system is an attractive approach used in MANETs which suffer from all kinds of uncertainty, randomness and vagueness. The scheme does not rely on any explicit feedback from the network and requires only sender side modifications. The simulation study examine the throughput, fairness index degree, packet loss percentage and packet delay as performance metrics of the ad hoc network with regard to equal sharing of network bandwidth among multiple TCP flows. The results observe that the proposed scheme achieves the desired goals of performance improvement in terms of packet loss and packet delay compared to TCP-Vegas, Reno and New Reno.

Novel Fastest Retransmission and Rate Control Schemes for Improving TCP Performance in Wireless Ad Hoc Networks

A number of different authors have considered the problem of performance degradation of transmission control protocol (TCP) in wireless ad hoc networks. We herein show that pauses in packet transmission due to packet losses are the fundamental cause of performance degradation of TCP in wireless ad hoc networks. To minimize the duration of packet transmission pauses, we propose a fast retransmission scheme for improving TCP performance in consideration of the inter-operability of previously deployed TCPs in wireless ad hoc networks. We also propose an additional rate control scheme for TCPs to reduce the probability of packet contention. Using OPNET and NS2 simulations, we show that our proposed schemes can provide a much better performance than conventional TCPs.

A MODEL FOR CONGESTION CONTROL OF TRANSMISSION CONTROL PROTOCOL IN MOBILE WIRELESS AD HOC NETWORKS

Transmission Control Protocol (TCP) is a fundamental protocol in the TCP/IP Protocol Suite.TCP was well designed and optimized to work over wired networks where most packet loss occurs due to network congestion. In theory, TCP should not care whether it is running over wired networks, WLANs, or Mobile Ad hoc Networks (MANETs). In practice, it does matter because most TCP deployments have been carefully designed based on the assumption that congestion is the main factor of network instability. However, MANETs have other dominating factors that cause network instability. Forgetting the impact of these factors violates some design principles of TCP congestion control and open questions for future research to address. This study aims to introduce a model that shows the impact of MANET factors on TCP congestion control. To achieve this aim, Design Research Methodology (DRM) proposed by BLESSING was used as a guide to present this model. The proposed model describes the existing situation of TCP congestion control. Furthermore, it points to the factors that are most suitable to be addressed by researchers in order to improve TCP performance. This research proposes a novel model to present the impact of MANET factors on TCP congestion control. The model is expected to serve as a benchmark for any intended improvement and enhancement of TCP congestion control over MANET.

Comparative Analysis of ADTCP and M-ADTCP: Congestion Control Techniques for Improving TCP Performance over Ad-Hoc Networks

Identifying the occurrence of congestion in a Mobile Ad -hoc Network (MANET) is a major task. The inbuilt congestion control techniques of existing TransmissionControl Protocol (TCP) designed for wired ne tworks do not handle the unique properties of shared wireless multi -hop link. There are several approaches proposed for detecting and overcoming the congestion in the mobile ad -hoc network. In this paper we present a Modified AD-hoc Transmission Control Protocol (M -ADTCP) method where the r eceiver detects the probable current network status and transmits this information to the sender as feedback. The sender behavior is altered appropriately. The proposedtechnique is also compatible with standard TCP .

Applications of network coding to improve TCP performance over wireless mesh networks: a survey

ABSTRACTThere is growing interest in the use of wireless mesh network (WMN) as a last‐mile option for Internet access. Despite the many benefits of WMNs, the performance of Internet access may not be ideal. One of the main issues is the interaction of transmission control protocol (TCP) with the underlying network. The poor performance of TCP over multi‐hop networks is well‐documented, and extensive research exists, which addresses TCPs foible and enhance TCP performance for multi‐hop environments. This paper provides a thorough survey of TCP performance issues over WMNs and the available solutions to address these issues. Among the existing methods, we focused on network coding (NC) and the ways that TCP interacts with network coded systems. NC is a technique that encodes the received packets in each node before forwarding them towards the destination. The use of NC in the transport layer to address performance issues raised by wireless access is a recent research topic. This paper presents a detailed study of TCP interaction with NC. Some open research areas in this field are suggested. Copyright © 2012 John Wiley & Sons, Ltd.

An Adaptive Delayed Acknowledgment Strategy to Improve TCP Performance in Multi-hop Wireless Networks

In multi-hop wireless networks, transmission control protocol (TCP) suffers from performance deterioration due to poor wireless channel characteristics. Earlier studies have shown that the small TCP acknowledgments consume as much wireless resources as the long TCP data packets. Moreover, generating an acknowledgment (ACK) for each incoming data packet reduces the performance of TCP. The main factor affecting TCP performance in multi-hop wireless networks is the contention and collision between ACK and data packets that share the same path. Thus, lowering the number of ACKs using the delayed acknowledgment option defined in IETF RFC 1122 will improve TCP performance. However, large cumulative ACKs will induce packet loss due to retransmission time-out at the sender side of TCP. Motivated by this understanding, we propose a new TCP receiver with an adaptive delayed ACK strategy to improve TCP performance in multi-hop wireless networks. Extensive simulations have been done to prove and evaluate our strategy over different topologies. The simulation results demonstrate that our strategy can improve TCP performance significantly.

Improving TCP performance in residential broadband networks

ADSL and cable connections are the prevalent technologies available from Internet Service Providers (ISPs) for residential Internet access. Asymmetric access technologies such as these offer high download capacity, but moderate upload capacity. When the Transmission Control Protocol (TCP) is used on such access networks, performance degradation can occur. In particular, sharing a bottleneck link with different upstream and downstream capacities among competing TCP flows in opposite directions can degrade the throughput of the higher speed link. Despite many research efforts to solve this problem in the past, there is no solution that is both highly effective and easily deployable in residential networks. In this paper, we propose an Asymmetric Queueing (AQ) mechanism that enables full utilization of the bottleneck access link in residential networks with asymmetric capacities. The extensive simulation evaluation of our design shows its effectiveness and robustness in a variety of network conditions. Furthermore, our solution is easy to deploy and configure in residential networks.

Resource Allocation Based on TCP Performance in Base Station Diversity Systems

This paper proposes a resource allocation method based on TCP (Transmission Control Protocol) throughput for base station diversity systems. A goal of this study is to achieve high throughput wireless Internet access by utilizing multiple wireless links effectively.The conventional work showed that base station diversity techniques can improve TCP performance. However, the improvement depends on the wireless environment of the wireless terminal.The proposed resource allocation method allocates wireless links to a wireless terminal based on its estimated TCP throughput and current traffic of each base station. Our method can take account of some network protocols such as TCP and UDP (User Datagram Protocol) by measuring the current traffic of each base station. In addition, wireless links are preferentially assigned to the wireless terminal that has the largest performance improvement per wireless link. Therefore, the proposal provides better overall system performance than the previous technique.

Optimal channel access for TCP performance improvement in cognitive radio networks

Cognitive radio (CR) is a promising technology to improve spectrum utilization. Most of previous work on CR networks concentrates on maximizing transmission rate in the physical layer. However, the end-to-end transmission control protocol (TCP) performance perceived by secondary users is also a very important factor in CR networks. In this paper, we propose a novel multi-channel access scheme in CR networks, where the channel access is based on the TCP throughput in the transport layer. Specifically, we formulate the channel access process in CR network as a restless bandit system. With this stochastic optimization formulation, the optimal channel access policy is indexable, meaning that the channels with highest indices should be selected to transmit TCP traffic. In addition, we exploit cross-layer design methodology to improve TCP throughput, where modulation and coding at the physical layer and frame size at the data-link layer are considered together with TCP throughput in the transport layer to improve TCP performance. Simulation results show the effectiveness of the proposed scheme.

Improving TCP performance over mobile ad hoc networks

The transmission control protocol (TCP) was designed to provide reliable end-to-end delivery of data over unreliable networks. Most TCP implementations have been carefully optimised to operate in wired networks. Deploying standard TCP in wireless mobile ad hoc networks (MANETs) can lead to poor performance of TCP. The main problem that faces TCP in ad hoc networks is its inability to distinguish between packet losses due to congestion and those due to route failures. In order to adapt TCP to MANET environment, several TCP improvements that differentiate between different types of packet losses using explicit notification messages from lower layers have been proposed. In this paper, we propose a new end-to-end technique that does not require any participation from intermediate nodes within the network. The proposed scheme relies on expanding the retransmission timeout (RTO) interval in order to reduce the number of timeouts that do not result from congestion. Simulation results show that our scheme can improve TCP throughput and delay. It outperformed the standard TCP in detailed simulation experiments.

Improving TCP performance for vertical handover in heterogeneous wireless networks

AbstractThe incorporation of wireless local area networks (WLANs) into existing cellular networks as supplementary access technologies has become an issue of great interest. However, vertical handover (VHO), which allows users to roam between a WLAN and a cellular network, causes an abrupt change in certain link characteristics such as the round trip time and data rate. Owing to such changes, reordering problem and premature timeout occur and trigger unnecessarily fast retransmission during VHO, causing throughput degradation. Thus, we propose a new transmission control protocol (TCP) mechanism, which resolves the reordering problem by suppressing unnecessary retransmission caused by spurious duplicate acknowledgments (dupacks) incurred because of the reordering problem, and prevents premature timeout by employing an adaptive retransmission timer. We analytically investigate the throughput of our proposed TCP scheme. The numerical and simulation results show that our proposed TCP performs better in terms of throughput than other schemes appearing in the literature. Copyright © 2009 John Wiley & Sons, Ltd.