Transport Control Protocol Performance Research Articles

PEPesc: A TCP Performance Enhancing Proxy for Non-Terrestrial Networks

Non-terrestrial networks (NTNs) using flying objects such as satellites play key roles in the next-generation wireless system (6 G). The NTN links with long propagation delay and random packet losses pose a great challenge to the performance of Transport Control Protocol (TCP), which many Internet applications rely on. Performance enhancing proxy (PEP) is an easy-to-deploy approach for improving TCP's performance. In this paper, we design and implement a novel PEP called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PEPesc</i> which has two distinctive features. First, it features <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">retransmission-free</i> loss recovery, using an adaptive packet-level forward erasure correction method called streaming coding (SC). Second, as packet losses are recovered by SC, the congestion control problem is simplified to rate control and local acknowledgement between entities based on bandwidth estimation. Based on a queueing theoretic analysis of the design, we carefully devise a protocol and implement PEPesc as an open-source application. Extensive evaluations show that PEPesc can achieve much higher <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">and</i> smoother goodput than the canonical TCP variants and than other existing open-source PEPs in applications including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">iperf</i> and HTTP-based adaptive streaming, and achieves similar performance in web browsing. Finally, we also present a deployment case over a real-world geostationary satellite link.

Performance Evaluation of QUIC Protocol in Message Replication Overhead in PBFT Consensus using NS-3

The development of protocols in the ICT world to increase reliability and speed in data traffic gave an inspiration to a new protocol called the QUIC protocol. The QUIC protocol is expected to improve the performance of Transport Control Protocol (TCP). In addition, developments also occur in blockchain technology where the protocol used in this technology still uses the existing TCP protocol. In this paper, we aimed to research whether the QUIC protocol implementation in blockchain infrastructure could improve the performance of the blockchain infrastructure itself, in terms of the time required for transactions. We focus on conducting research to measure the overhead time reduction of Practical Byzantine Fault Tolerance (PBFT) consensus by implementing the QUIC protocol, the consensus propagation process is a crucial phase in Blockchain. For simulation we used NS-3 discrete simulation environment to conduct scenario and our simulation result showed that the QUIC Protocol have potential significant performance compared to TCP Protocol in large datasets, on the other hand QUIC protocols have more room for improvement by implementing appropriate congestion algorithms.

A Performance Analysis Model of TCP over Multiple Heterogeneous Paths for 5G Mobile Services

Driven by the primary requirement of emerging 5G mobile services, the demand for concurrent multipath transfer (CMT) is still prominent. Yet, multipath transport protocols are not widely adopted and CMT schemes based on Transport Control Protocol (TCP) will still be in dominant position in 5G. However, the performance of TCP flow transferred over multiple heterogeneous paths is prone to the link quality asymmetry, the extent of which was revealed to be significant by our field investigation. In this paper, we present a performance analysis model for TCP over multiple heterogeneous paths in 5G scenarios, where both bandwidth and delay asymmetry are taken into consideration. The evaluation using large-scale simulation and field experiment shows that the proposed model can achieve high accuracy in practical environments. Some interesting inferences can be drawn from the proposed model, such as the dominant factors that affect the performance of TCP over heterogeneous networks, and the criteria of determining the appropriate number of links to be used under different circumstances of path heterogeneity. Thus, the proposed model can provide a guidance to the design of TCP-based CMT solutions for 5G mobile services.

AN EVALUATION OF MANET PROTOCOLS IN TERMS OF TCP VARIANTS BASED ON THIER PERFORMANCES USING OPNETT

MANET stands for Mobile Ad-Hoc network which means an on-demand network with n number of mobile nodes, each connected to one another through wireless connections. These networks has many advantages over the traditional wireless networks such as ease of setting up, no need for infrastructure etc. Due to the presence of mobility in the MANET, the interconnections between stations are likely to change on a continual basis, resulting in frequent changes of network topology. The transport control protocol (TCP) is responsible for providing reliable data transport in the Internet. As a matter of fact, it is extensively tuned to providing high-quality performance in the conventional wired network. However, it cannot offer reliable service while using e-mail, internet search, several application file transmission in a mobile Ad-hoc network. Several studies reveal that TCP does not perform as well in a mobile environment as it does in other networks. There are several factors that affect the TCP performance in MANETs, such as dynamic topology, shared medium, signal fading and high bit errors. , there are other factors like network size, network load, bandwidth and signal strength that affect the performance of the MANET routing protocols. Therefore, a detailed analysis is required in order to gain an insight of these factors that determine the performance of the routing protocol. So in this paper we will be discoursing different aspects of the network design. The measurements were taken in the light of throughput, end to end delay etc using DSR and AODV protocols of MANET. Simulation is done in Optimized Network Engineering Tool14.5 (OPNET 14.5).

Achieving high throughput and TCP Reno fairness in delay-based TCP over large networks

The transport control protocol (TCP) has been widely used in wired and wireless Internet applications such as FTP, email and http. Numerous congestion avoidance algorithms have been proposed to improve the performance of TCP in various scenarios, especially for high speed and wireless networks. Although different algorithms may achieve different performance improvements under different network conditions, designing a congestion algorithm that can perform well across a wide spectrum of network conditions remains a great challenge. Delay-based TCP has a potential to overcome above challenges. However, the unfairness problem of delay-based TCP with TCP Reno blocks widely the deployment of delay-based TCP over wide area networks. In this paper, we proposed a novel delay-based congestion control algorithm, named FAST-FIT, which could perform gracefully in both ultra high speed networks and wide area networks, as well as keep graceful fairness with widely deployed TCP Reno hosts. FAST-FIT uses queuing delay as a primary input for controlling TCP congestion window. Packet loss is used as a secondary signal to adaptively adjust parameters of primary control process. Theoretical analysis and experimental results show that the performance of the algorithm is significantly improved as compared to other state-of-the-art algorithms, while maintaining good fairness.

무선 메쉬 네트워크에서 TCP 성능 향상 기법

Wireless mesh network is similar to ad-hoc network, so when transferred to the data packet in the wireless environment, interfered factor arise. When TCP(Transport Control Protocol) was created, however as it was design based on wired link, wireless link made more transmission error than wired link. It is existent problem that TCP unfairness and congestion collapse over wireless mesh network. But packet losses due to transmission errors are more frequent. The cause of transmission error in wireless ad-hoc network may be inexactly regarded as indications of network congestion. And then, Congestion Control Algorithm was running by this situation causes the TCP performance degradation. In this paper, proposed TCP can adaptively regulate the congestion window through moving node in the Wireless Mesh Network. And it enhanced the performance.

TCP and web browsing performance in case of bi-directional packet loss

Performance modeling of the transport control protocol (TCP) has received a lot of attention over the past few years. The most commonly quoted results are approximate formulas for TCP throughput (Padhye et al. (2000) [1]) and document download times (Cardwell et al. (2000) [2]) which are used for dimensioning of IP networks. However, the existing modeling approaches unanimously assume that packet loss only occurs for packets from the server to the client, whereas in reality the packets in the direction from the client to the server may also be dropped. Our simulations with NS-2 show that this bi-directional packet loss indeed may have a strong impact on TCP performance. Motivated by this, we refine the models in Padhye et al. (2000) [1] and Cardwell et al. (2000) [2] by including bi-directional packet loss, also including correlations between packet loss occurrences. Simulations show that the proposed model leads to strong improvements of the accuracy of the TCP performance predictions. In addition we show how our model can be used to predict quality of experience for web browsing sessions.

Rate Control Algorithm Considering Mobility in Mobile Ad Hoc Networks

For reducing the loss of data packet due to network congestion and mobility, rate control algorithm is effective means for ensuring the fair allocation of network resource among communication flows and alleviating network congestion. The Transport Control Protocol (TCP) was originally designed for wire-line networks, where the links are assumed to be reliable and with fixed capacities. However, the performance of TCP becomes very poor when it is directly used in ad hoc networks. Some optimization-based congestion control schemes have been proposed to improve TCP performance in ad hoc networks, but the mobility of hosts and route change frequently are not considered for designing rate control algorithm. In this paper, we propose rate control algorithms in a more practical way by taking into account link congestion and node movement. Numerical results show that the rate control algorithms can approach the globally optimal value and show the effect of the node mobility on the algorithms.

Loss classification in optical burst switching networks using machine learning techniques: improving the performance of TCP

Optical burst switching (OBS) is considered as a contending technology for the core of the Internet in future. However, due to lack of the buffers, losses occur due to contention among simultaneously arriving bursts at the core nodes. Contention losses do not necessarily indicate a situation of congestion in the network. Thus differentiation (classification) of losses is essential in many applications to avoid false identification of congestion. In this paper, we propose a loss classification technique for the OBS networks based on machine learning techniques. We devise a new measure to differentiate between congestion and contention losses, which is derived from the observed losses, called the number of bursts between failures (NBBF). We observe that the NBBF follows a Gaussian distribution with different parameters for contention and congestion losses. This feature is used in differentiation. We use both a supervised learning technique (hidden Markov model (HMM)) and an unsupervised learning technique (expectation maximization (EM) clustering) on the observed losses and classify them into a set of states (clusters) after which an algorithm differentiates between the congestion and contention losses. We also demonstrate the use of loss differentiation in improving the performance of transport control protocol (TCP) over OBS networks. We modify congestion control mechanism of TCP suitably to arrive at two variants of TCP, HMM-TCP and EM-TCP. Their performance is compared with TCP NewReno, TCP SACK, and Burst TCP (X. Yu et al., Mar. 2004). Simulation results demonstrate the effectiveness and accuracy of the loss classification technique in different network scenarios.

Efficient enhancing scheme for TCP performance over satellite-based internet

Abstract Satellite link characteristics drastically degrade transport control protocol (TCP) performance. An efficient performance enhancing scheme is proposed. The improvement of TCP performance over satellite-based Internet is accomplished by protocol transition gateways at each end of a satellite link. The protocol which runs over a satellite link executes the receiver-driven flow control and acknowledgements- and timeouts-based error control strategies. The validity of this TCP performance enhancing scheme is verified by a series of simulation experiments. Results show that the proposed scheme can efficiently enhance the TCP performance over satellite-based Internet and ensure that the available bandwidth resources of the satellite link are fully utilized.

Shielding TCP from last hop wireless losses

AbstractThe pervasiveness of the transport control protocol (TCP) and the proliferation of wireless local area networks (WLAN) of the 802.11 type make the topic of TCP performance over last hop wireless networks very relevant. The Snoop protocol, a link layer solution introduced several years ago to improve the performance of TCP in this scenario, has been shown to neglect its benefits to the most widely used TCP version, TCP SACK. In this paper, we introduce the TCP SACK‐Aware Snoop protocol to address this problem. Our results indicate that the TCP SACK‐Aware Snoop protocol improves the performance of TCP SACK by around 30% compared with the original Snoop protocol and by about 8% in an environment where no TCP enhancing mechanism is in place. In addition, we introduce further modifications to the proposed protocol to make its advantages available to any TCP sender. We also show that the mechanism does not introduce unfairness among TCP sources and somewhat protects TCP against UDP traffic. Our results show important throughput improvements to all TCP versions and demonstrate that the TCP SACK‐Aware Snoop protocol shields TCP from last hop wireless losses providing throughtput values very close to the maximum possible. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Improving TCP Performance in Mobile Networks

In this letter, a new transport layer mechanism is proposed to improve the performance of transport control protocol (TCP) in mobile networks. The proposed mechanism is comprised of two parts: a loss classifier (LC) and a congestion window extrapolator (CWE). Based on LC, the cause of packet loss during roaming is determined. If the loss is considered to be caused by congestion in the wireline, the congestion window is halved; otherwise, the packet is considered to be lost in the last hop, the wireless portion, and the sender adjusts the size of the congestion window based on CWE. We conduct simulations to evaluate the performance of the proposed mechanism. The results show that our mechanism significantly improves TCP performance as compared with existing solutions for mobile networks.

Accurate Analysis of TCP on Channels With Memory and Finite Round-Trip Delay

In this paper, we present an accurate analytical model for transport control protocol (TCP) over correlated channels (e.g., as induced by multipath fading) taking into account a finite round-trip delay. In particular, we develop models and analysis for studying four versions of TCP, namely, Old Tahoe, Tahoe, Reno, and New Reno. We focus on a single wireless TCP connection by modeling the correlated packet loss/error process as a Discrete Time first-order Markov chain. Our model explicitly incorporates important aspects such as slow start, congestion avoidance, fast retransmit and fast recovery. The main findings of this study are that: 1) an increasing round-trip time may significantly affect the throughput performance of TCP, especially when an independent channel is considered; 2) New Reno performs better than Reno and Tahoe when the channel is uncorrelated, whereas Tahoe's recovery strategy is the most efficient when the channel correlation is high; and 3) the maximum window size does not play a determinant role in increasing throughput performance in both correlated and independent channels. While some of these conclusions confirm what other authors have observed in simulation studies, our analytical approach sheds some new light on TCP's behavior.

Comparing TCP variants in presence of reverse traffic

A comparison of the performance of transport control protocol (TCP) congestion control variants: Reno, Vegas, and SACK in the presence of varying reverse traffic is presented. A new metric called adjusted utilisation, which is based on both link utilisation and fairness, is introduced in the comparison.

A reconfigurable protocol setting to improve TCP over wireless

Wireless access to the Internet requires that information integrity be preserved while transmitting data over the radio channel. Automatic repeat request (ARQ) schemes and transport control protocol (TCP) are often used as error-control techniques at the link layer and at the transport layer, respectively. In this paper, we study the interactions between an ARQ protocol and TCP when the last hop of the connection path is wireless. Link layer retransmissions are used to hide losses over the wireless link to TCP and to avoid that TCP interprets these losses as signs of network congestion. By adapting the protocol parameter setting at the link and transport layers to the time-varying characteristics of the wireless channel, we obtain a reliable communication link in spite of disadvantageous radio channel conditions. The number of retransmissions of the ARQ scheme and the TCP segment size can be set to proper values that, given certain propagation conditions, enable the desired quality of service (QoS) at the transport layer. In order to derive the protocol parameter setting fulfilling the QoS requirements, we develop detailed models of the ARQ protocol and TCP by using standard Markovian techniques. Through these models, the impact of the link layer functions on the TCP performance is evaluated in the presence of different wireless environments.

Efficient Integration of IP-Based Terrestrial and Satellite Systems: ARQTechniques and Inter-Segment Handover

A satellite communication system is an excellent candidate to provide broadband integrated Internet services to globally scattered users. The inter-operation between a satellite system and the existing terrestrial Internet infrastructure introduces new challenges at different layers. Automatic Repeat reQuest (ARQ) techniques have been introduced at radio link layer to improve the performance of Transport Control Protocol (TCP)/IP over wireless terrestrial links, but these techniques are usually dismissed in presence of high latency links such as satellite links. In this paper, we will show that a truncated power control can effectively improve the trade-off delay-residual error after retransmissions and makes ARQ techniques a feasible solution for error control in satellite links. Furthermore, mobility management issues in presence of satellite diversity are addressed. Performance of an Inter-Segment Hand-Over (ISHO) procedure, in terms of propagation delay, will be carried out through simulation for different space segment configurations.

Comparative performance analysis of versions of TCP in a local network with a lossy link

We use a stochastic model to study the throughput performance of various transport control protocol (TCP) versions (Tahoe (including its older version that we call OldTahoe), Reno, and NewReno) in the presence of random losses on a wireless link in a local network. We model the cyclic evolution of TCP, each cycle starting at the epoch at which recovery starts from the losses in the previous cycle. TCP throughput is computed as the reward rate in a certain Markov renewal-reward process. Our model allows us to study the performance implications of various protocol features, such as fast retransmit and fast recovery. We show the impact of coarse timeouts. In the local network environment the key issue is to avoid a coarse timeout after a loss occurs. We show the effect of reducing the number of duplicate acknowledgements (ACKs) for triggering a fast retransmit. A large coarse timeout granularity seriously affects the performance of TCP, and the various protocol versions differ in their ability to avoid a coarse timeout when random loss occurs; we quantify these differences. We show that, for large packet-loss probabilities, TCP-Reno performs no better, or worse, than TCP-Tahoe. TCP-NewReno is a considerable improvement over TCP-Tahoe, and reducing the fast-retransmit threshold from three to one yields a large gain in throughput; this is similar to one of the modifications in the TCP-Vegas proposal. We explain some of these observations in terms of the variation of fast-recovery probabilities with packet-loss probability. The results of our analysis compare well with a simulation that uses actual TCP code.

The effect of correlated errors on the performance of TCP

Wireless channels are known to introduce correlated bursts of errors at the physical layer. Although these errors affect the performance at all layers of a protocol stack, their precise impact, especially at the higher layers, is not completely understood. We study the effect of error correlations on the throughput of a single transport control protocol (TCP) Tahoe connection. We find that TCP Tahoe performs better in the presence of clustered errors. This suggests that techniques that reduce channel memory may be undesirable.

Dynamics of TCP traffic over ATM networks

Investigates the performance of transport control protocol (TCP) connections over ATM networks without ATM-level congestion control and compares it to the performance of TCP over packet-based networks. For simulations of congested networks, the effective throughput of TCP over ATM can be quite low when cells are dropped at the congested ATM switch. The low throughput is due to wasted bandwidth as the congested link transmits cells from corrupted packets, i.e., packets in which at least one cell is dropped by the switch. The authors investigate two packet-discard strategies that alleviate the effects of fragmentation. Partial packet discard, in which remaining cells are discarded after one cell has been dropped from a packet, somewhat improves throughput. They introduce early packet discard, a strategy in which the switch drops whole packets prior to buffer overflow. This mechanism prevents fragmentation and restores throughput to maximal levels. >