Transmission Control Protocol ACK Research Articles

A survey of transmission control protocol variants

TCP (Transmission Control Protocol), is a reliable connection oriented end-to-end protocol. It contains within itself, mechanisms for ensuring reliability by requiring the receiver to acknowledge the segments that it receives. The network is not perfect and a small percentage of packets are lost enroute, either due to network error or due to the fact that there is congestion in the network and the routers are dropping packets. TCP ensures reliability by starting a timer whenever it sends a segment. If it does not receive an acknowledgement from the receiver within the ‘time-out’ interval then it retransmits the segment. In this paper a review of various TCP is carried out. There are a number of TCP variants for application in the management of network efficiency in terms of network congestion and transmission efficiency. These variants include: - TCP Tahoe, TCP Reno, TCP New Reno, TCP Vegas, TCP SACK, TCP FACK, TCP Asym, TCP RBP, Full TCP and TCP CUBIC. Therefore, the main objective of this paper is to study the tcp types on the network performance variances. All have different features and advantages but with maximal throughput as main objective, which are termed as the clones of TCP, have been incorporated into TCP/IP protocol for handling congestion efficiently in different network scenarios.

Performance Evaluation of Reactive Routing Protocols in MANETs in Association with TCP Newreno

We inspect the performance of TCP NewReno protocol for data transfer in Mobile Ad hoc networks (MANETs). Dynamic Source Routing (DSR) protocols and AdHoc On-demand Distance Vector (AODV) are standard reactive routing protocols widely used in MANETs. In addition we also have to consider Transmission Control Protocol (TCP) as essential for MANETs since it is one of the widely used internet protocol for dependable data transmission. TCP has its variants namely TCP Reno, TCP NewReno , TCP Vegas and TCP SACK. In this paper we are evaluating the performance of DSR and AODV in association with TCP Newreno with respect to various parameters such as Average throughput, instant throughput, residual energy, packet delivery ratio. The ns-2 network simulator was used for simulation.

RESEARCH ON TCP/IP CONGESTION CONTROL BASED ON NS-2 NETWORK SIMULATION PLATFORM

The emergence of the Internet facilitates people's lives. Although the network bandwidth increases rapidly, channel resources are limited and network congestion is bound to occur. In order to alleviate network congestion and improve service quality, this paper simply introduced four transmission control protocol (TCP) congestion control algorithms and network simulation-2 (NS-2) network simulation platform for simulating the network environment. Then the performance of four TCP congestion control algorithms in congested network and high bandwidth networks is simulated and analyzed on NS-2 simulation platform. The results showed that TCP Vegas has stable performance in both congested and high-bandwidth networks, and not only the change of cwnd is stable, but also the total number of packets sent and the average throughput are more, and the packet loss rate is 0; the performance of the other three algorithms is consistent in high bandwidth network, In crowded networks, TCP Tahoe performs worst, TCP Reno performs generally, and TCP SACK performs well; TCP Vegas performs poorly on average latency. In summary, TCP Vegas can be used stably in congested networks and high bandwidth networks, but considering the average delay, it is more inclined to apply the other three algorithms in high bandwidth networks.

Detecting TCP ACK storm attack: a state transition modelling approach

Ack-storm DoS attacks are injection attacks against an active Transmission Control Protocol (TCP) connection. These attacks can be generated by a very weak adversary and can generate amplification factor of orders of magnitude by exploiting a weakness in the TCP protocol specification. This attack requires sending two packets by the adversary with acknowledgement number greater than the sequence number used in each direction and the two end hosts will attempt to re-synchronise the sequence numbers by sending duplicate acknowledgement and enter a loop. In this study, the authors propose a state transition model based detection scheme to detect these DoS attacks. This state transition machine called constrained counting automata ( CCA ) has the ability to count the number of times a state has been revisited and its transitions are constrained by invariant conditions to be satisfied. They model the chances of receiving a packet with acknowledgement number greater than the sequence number used by its peer as a probability distribution and use it to set appropriate value of threshold on revisits of a state for detecting attack. By experimenting within a local network and in Internet, they show that CCA can detect Ack-storm DoS attacks .

Packet Recycling and Delayed ACK for Improving the Performance of TCP over MANETs

Most of the schemes that were proposed to improve the performance of transmission control protocol (TCP) over mobile ad hoc networks (MANETs) are based on a feedback from the network, which can be expensive (require extra bandwidth) and unreliable. Moreover, most of these schemes consider only one cause of packet loss. They also resume operation based on the same stand-by parameters that might vary in the new route. Therefore, we propose two techniques for improving the performance of TCP over MANETs. The first one, called TCP with packet recycling (TCP-PR), allows the nodes to recycle the packets instead of dropping them after reaching the retransmission limit at the MAC layer. In the second technique, which is called TCP with adaptive delay window (TCP-ADW), the receiver delays sending TCP ACK for a certain time that is dynamically changed according to the congestion window and the trip time of the received packet. TCP-PR and TCP-ADW are simple, easy to implement, do not require network feedback, compatible with the standard TCP, and do not require distinguishing between the causes of packet loss. Our thorough simulations show that the integration of our two techniques improves the performance of TCP over MANETs.

Performance Comparison between TCP Sack and TCP Vegas using NS-2 Simulator

In this paper, two TCP variants are compared in different scenario. Transmission Control Protocol (TCP) is a reliable, end-to-end transport protocol which is most widely used for data services and is very efficient for wired networks. It also performs well in wireless networks. It is the backbone protocol of most of the internet based applications. Our analysis is on performance of TCP variants. In this paper we carry out performance study of TCP Sack and TCP Vegas to be able to classify which variant of TCP performs better in various possible scenarios. This paper describes an NS-2 based simulation analysis. By varying different parameters and congestion control mechanism we will check its effect on Throughput.

Modeling TCP SACK performance over wireless channels with completely reliable ARQ/FEC

AbstractIn this paper, we propose an analytical cross‐layer model for a Transmission Control Protocol (TCP) connection running over a covariance‐stationary wireless channel with a completely reliable Automatic Repeat reQuest scheme combined with Forward Error Correction (FEC) coding. Since backbone networks today are highly overprovisioned, we assume that the wireless channel is the only one bottleneck in the system which causes packets to be buffered at the wired/wireless interface and dropped as a result of buffer overflow. We develop the model in two steps. At the first step, we consider the service process of the wireless channel and derive the probability distribution of the time required to successfully transmit an IP packet over the wireless channel. This distribution is used at the next step of the modeling, where we derive expressions for the TCP long‐term steady‐state throughput, the mean round‐trip time, and the spurious timeout probability. The developed model allows to quantify the joint effect of many implementation‐specific parameters on the TCP performance over both correlated and non‐correlated wireless channels. We also demonstrate that TCP spurious timeouts, reported in some empirical studies, do not occur when wireless channel conditions are covariance‐stationary and their presence in those measurements should be attributed to non‐stationary behavior of the wireless channel characteristics. Copyright © 2011 John Wiley & Sons, Ltd.

Implementing an adaptive TCP fairness while exploiting 802.11e over wireless mesh networks

PurposeThe purpose of this paper is to investigate the use of 802.11e MAC to resolve the transmission control protocol (TCP) unfairness.Design/methodology/approachThe paper shows how a TCP sender may adapt its transmission rate using the number of hops and the standard deviation of recently measured round‐trip times to address the TCP unfairness.FindingsSimulation results show that the proposed techniques provide even throughput by providing TCP fairness as the number of hops increases over a wireless mesh network (WMN).Research limitations/implicationsFuture work will examine the performance of TCP over routing protocols, which use different routing metrics. Other future work is scalability over WMNs. Since scalability is a problem with communication in multi‐hop, carrier sense multiple access (CSMA) will be compared with time division multiple access (TDMA) and a hybrid of TDMA and code division multiple access (CDMA) will be designed that works with TCP and other traffic. Finally, to further improve network performance and also increase network capacity of TCP for WMNs, the usage of multiple channels instead of only a single fixed channel will be exploited.Practical implicationsBy allowing the tuning of the 802.11e MAC parameters that have previously been constant in 802.11 MAC, the paper proposes the usage of 802.11e MAC on a per class basis by collecting the TCP ACK into a single class and a novel congestion control method for TCP over a WMN. The key feature of the proposed TCP algorithm is the detection of congestion by measuring the fluctuation of RTT of the TCP ACK samples via the standard deviation, plus the combined the 802.11e AIFS and CWmin allowing the TCP ACK to be prioritised which allows the TCP ACKs will match the volume of the TCP data packets. While 802.11e MAC provides flexibility and flow/congestion control mechanism, the challenge is to take advantage of these features in 802.11e MAC.Originality/valueWith 802.11 MAC not having flexibility and flow/congestion control mechanisms implemented with TCP, these contribute to TCP unfairness with competing flows.

Performance improvement of TCP in ad hoc networks by mitigating channel contention

AbstractIn ad hoc networks, the spatial reuse property limits the number of packets which can be spatially transmitted over a path. In standard Transmission Control Protocol (TCP), however, a TCP sender keeps transmitting packets without taking into account this property. This causes heavy contention for the wireless channel, resulting in the performance degradation of TCP flows. Hence, two techniques have been proposed independently in order to reduce the contention. First, a TCP sender utilizes a congestion window limit (CWL), by considering the spatial reuse property. This prevents the TCP sender from transmitting more than CWL number of packets at one time. Second, a delayed ack (DA) strategy is exploited in order to mitigate the contention between the TCP ACK and DATA packets. Recently, although TCP‐DAA (Dynamic Adaptive Acknowledgment) attempts to utilize a CWL‐based DA strategy, TCP‐DAA overlooks a dynamic correlation between these two techniques. This paper, therefore, reveals the dynamic correlation and also proposes a protocol which not only reduces the frequency of the TCP ACK transmissions but also determines a CWL value dynamically, according to network conditions. Simulation studies show that our protocol performs the best in various scenarios, as compared to TCP‐DAA and standard TCP (such as TCP‐NewReno). Copyright © 2009 John Wiley & Sons, Ltd.

Estimation of packet losses due to propagation impairments: Application to TCP performance over satellite

AbstractThe transmission control protocol (TCP) is widely used to provide reliable data transmission due to its congestion and flow control mechanisms that provide reliable error recovery in higher layers. In satellite links, various atmospheric phenomena may lead to high packet loss rate (PLR) degrading the TCP throughput. Modern satellite systems operate at frequencies above 10 GHz, where rainfall is the dominant fading mechanism leading to high bit error ratio and correlated packet losses. In this paper, a mathematical analysis is presented to accurately describe the statistical properties of the packet‐error process in a dynamically varying satellite channel. The proposed method is extended to provide PLR estimations when block forward error correction (FEC) is employed. A new Markov‐based method, based on the previous analysis and adapted to the rain‐faded satellite channel, is also presented for the estimation of TCP SACK throughput and tested against simulation results. Based on the information provided by the packet‐error model, a study between the TCP performance under various FEC schemes and a proposed adaptive FEC scheme has provided indications about the superiority of the proposed model. Copyright © 2007 John Wiley & Sons, Ltd.