To Transmission Control Protocol Research Articles

Analysis of Retransmission Policies for Parallel Data Transmission

Stream control transmission protocol (SCTP) is a transport layer protocol, which is efficient, reliable, and connection-oriented as compared to transmission control protocol (TCP) and user datagram protocol (UDP). Additionally, SCTP has more innovative features like multihoming, multistreaming and unordered delivery. With multihoming, SCTP establishes multiple paths between a sender and receiver. However, it only uses the primary path for data transmission and the secondary path (or paths) for fault tolerance. Concurrent multipath transfer extension of SCTP (CMT-SCTP) allows a sender to transmit data in parallel over multiple paths, which increases the overall transmission throughput. Parallel data transmission is beneficial for higher data rates. Parallel transmission or connection is also good in services such as video streaming where if one connection is occupied with errors the transmission continues on alternate links. With parallel transmission, the unordered data packets arrival is very common at receiver. The receiver has to wait until the missing data packets arrive, causing performance degradation while using CMT-SCTP. In order to reduce the transmission delay at the receiver, CMT-SCTP uses intelligent retransmission polices to immediately retransmit the missing packets. The retransmission policies used by CMT-SCTP are RTX-SSTHRESH, RTX-LOSSRATE and RTX-CWND. The main objective of this paper is the performance analysis of the retransmission policies. This paper evaluates RTX-SSTHRESH, RTX-LOSSRATE and RTX-CWND. Simulations are performed on the Network Simulator 2. In the simulations with various scenarios and parameters, it is observed that the RTX-LOSSRATE is a suitable policy.

Congestion Control for Background Data Transfers With Minimal Delay Impact

Congestion control protocols for background data are commonly conceived and designed to emulate low priority traffic, which yields to transmission control protocol (TCP) flows. In the presence of even a few very long TCP flows, this behavior can cause bandwidth starvation, and hence, the accumulation of large numbers of background data flows for prolonged periods of time, which may ultimately have an adverse effect on the download delays of delay-sensitive TCP flows. In this paper, we look at the fundamental problem of designing congestion control protocols for background traffic with the minimum impact on short TCP flows while achieving a certain desired average throughput over time . The corresponding optimal policy under various assumptions on the available information is obtained analytically. We give tight bounds of the distance between TCP-based background transfer protocols and the optimal policy, and identify the range of system parameters for which more sophisticated congestion control makes a noticeable difference. Based on these results, we propose an access control algorithm for systems where control on aggregates of background flows can be exercised, as in file servers. Simulations of simple network topologies suggest that this type of access control performs better than protocols emulating low priority over a wide range of parameters.

Throughput optimization of TCP incast congestion control in large-scale datacenter networks

The many-to-one traffic pattern in datacenter networks leads to Transmission Control Protocol (TCP) incast congestion and puts unprecedented pressure to cloud service providers. The abnormal TCP behaviors in incast increase system response time and unavoidably reduce the applicability of cloud-based system deployments. This paper proposes Receiver-oriented Congestion Control (RCC) to address heavy incast in large-scale datacenter networks. RCC is motivated by oscillatory queue size of switch when handling heavy incast and substantial potential of receiver in congestion control when using TCP. RCC makes effective use of centralized scheduler and Explicit Congestion Notification (ECN) at receiver. The RCC prototype is realized in network simulator 3 (ns3) which implements TCP exactly. This paper details the RCC design and evaluates its performance in diverse and heavy workloads. The evaluation results indicate that RCC has an average decreases of 47.5% in the mean queue size and 51.2% in the 99th-percentile latency in the heavy incast over TCP.

Opportunistic Hybrid Transport Protocol (OHTP) for Cognitive Radio Ad Hoc Sensor Networks.

The inefficient assignment of spectrum for different communications purposes, plus technology enhancements and ever-increasing usage of wireless technology is causing spectrum scarcity. To address this issue, one of the proposed solutions in the literature is to access the spectrum dynamically or opportunistically. Therefore, the concept of cognitive radio appeared, which opens up a new research paradigm. There is extensive research on the physical, medium access control and network layers. The impact of the transport layer on the performance of cognitive radio ad hoc sensor networks is still unknown/unexplored. The Internet’s de facto transport protocol is not well suited to wireless networks because of its congestion control mechanism. We propose an opportunistic hybrid transport protocol for cognitive radio ad hoc sensor networks. We developed a new congestion control mechanism to differentiate true congestion from interruption loss. After such detection and differentiation, we propose methods to handle them opportunistically. There are several benefits to window- and rate-based protocols. To exploit the benefits of both in order to enhance overall system performance, we propose a hybrid transport protocol. We empirically calculate the optimal threshold value to switch between window- and rate-based mechanisms. We then compare our proposed transport protocol to Transmission Control Protocol (TCP)-friendly rate control, TCP-friendly rate control for cognitive radio, and TCP-friendly window-based control. We ran an extensive set of simulations in Network Simulator 2. The results indicate that the proposed transport protocol performs better than all the others.

A survey on TCP Incast in data center networks

SUMMARYIn high bandwidth, low latency data center networks, when multiple data senders simultaneously communicate with a single receiver, namely in many‐to‐one communication pattern, the burst data overload the receiver's switch buffers, which leads to Transmission Control Protocol (TCP) throughput collapse. This is the so‐called TCP Incast problem. It has become a new hot research topic in recent years. Also, many proposals have been put forward from the aspects of multiple layers including link layer, transport layer, and application layer, etc., to mitigate TCP Incast. In this paper, an in‐depth survey on these proposals is given, and the principles, merits, and drawbacks of the main proposals for solving the TCP Incast issue are analyzed and summarized. Copyright © 2012 John Wiley & Sons, Ltd.

SGTP: Smart Grid Transport Protocol for secure reliable delivery of periodic real time data

In emerging smart grid networks, massive amounts of data will be continuously generated from measurement devices embedded in the power grid such as phasor management units (PMUs), intelligent electronic devices, advanced meters, or electric vehicle charging stations. Data generated from these measurement devices must be delivered immediately, reliably, and safely to specific locations for wide-area monitoring and grid control. The transport requirements for periodic measurement data are characterized as continual, reliable, and secure delivery of small-sized packets (less than 1.5 KB) over a utility-owned wide area network (WAN). Motivated by our assessment that no well-known transport protocol adequately meets these requirements, we designed the Smart Grid Transport Protocol (SGTP) for smart grid networking. Compared to Transmission Control Protocol (TCP), we show through simulation studies that SGTP can indeed achieve lower latency while preserving reliability and lightweight communication overhead and supporting inherent security extensions.

English

  Despite the larger performance and higher throughput compared to transmission control protocol (TCP) Reno, TCP Vegas still has a few obstacles to be deployed in new networks, such as 4G LTE systems (4th Generation, Long term evolution). One of these obstacles is the Vegas congestion control that is not used in all available bandwidth capacity of the network path and which causes minimization in packet quantity transferred from source to destination. However, many researches have shown unfair treatment of TCP Vegas connections when they compete with Reno connections. So, Vegas need more developments and more modifications to be efficient over bidirectional links with unbalanced traffic, and on wireless links. TCP-Vegas is a congestion control algorithm that reduces queuing and packet loss, and thus reduces latency and increases overall throughput, by carefully matching the sending rate to the rate at which packets are successfully being drained by the network. This paper presents results from a series of simulation experiments designed to study TCP Vegas performance in LTE network model using NS-2 network simulator. The characterization and analysis of Vegas behavior performed using the main two parameters, alpha and beta, to configure the congestion window (cwnd) phases. After used multiple values, the configuration results show that TCP Vegas perform better than TCP Reno.   Key words: Transmission control protocol; TCP-Vegas, cwnd, long term evolution (LTE), NS-2.

Optimal design of forward error correction for fairness maximisation among transmission control protocol flavours over wireless networks

A plethora of modifications to transmission control protocol (TCP) have recently been proposed, a major aim being to improve its performance over wireless links. Two schools of thought have emerged: the first investigates changes to the transport-layer protocol, whereas the second explores the potential to enhance the characteristics of lower layers to improve the end-to-end performance of TCP. This study focuses on the latter, and, in contrast to most research in this area, which thus-far has concentrated on a single TCP flavour, examines the case where different TCP flavours are competing over a wireless link. To this end, the authors present and assess a cross-layer solution to adapt the coding rate at the link-layer based on the detected TCP flavour, to maximise fairness among TCP flows. Through both analysis and simulation, the authors show that the proposed scheme considerably improves the fairness among different TCP flavours that compete over a wireless link. Furthermore, the proposed approach has minimal detrimental effect on the aggregate throughput of TCP flows.

Providing proportional TCP performance by fixed-point approximations over bandwidth on demand satellite networks

In this paper we focus on the provision of proportional class-based service differentiation to transmission control protocol (TCP) flows in the context of bandwidth on demand (BoD) split-TCP geostationary (GEO) satellite networks. Our approach involves the joint configuration of TCP-Performance Enhancing Proxy (TCP-PEP) agents at the transport layer and the scheduling algorithm controlling the resource allocation at the Medium Access Control (MAC) layer. We show that the two differentiation mechanisms exhibit complementary behavior in achieving the desired differentiation throughout the traffic load space: the TCP-PEPs control differentiation at low and medium system utilization, whereas the MAC scheduler becomes the dominant differentiation factor under high traffic load. The main challenge for the satellite operator is to appropriately configure those two mechanisms to achieve a specific differentiation target for the different classes of TCP flows. To this end, we propose a fixed-point framework to analytically approximate the achieved differentiated TCP performance. We validate the predictive capacity of our analytical method via simulations and show that our approximations closely match the performance of different classes of TCP flows under various scenarios for the network traffic load and configuration of the MAC scheduler and TCP-PEP agent. Satellite network operators could use our approximations as an analytical tool to tune their networks.

A power efficient solution to the large interference range problem in ad hoc networks

AbstractDue to the mismatch between the transmission range and interference‐vulnerable range, the reception at a receiving node in a wireless network could still be interfered by a sending node beyond the coverage of its clear‐to‐send (CTS). This is the so‐called large interference range problem. It is a common problem in real environments but overlooked by the standards and related studies. The large interference range problem could lead to transmission control protocol (TCP) instability and TCP unfairness, especially in case of multi‐hop transmission. There exist research works devoted to this issue. However, more power consumption was incurred at the same time. For a power‐efficient solution to this problem, a novel scheme, named power control interference avoidance (PCIA), is developed and presented in this article. The proposed scheme decouples control channel from data channel and use different power level in the transmission of control frames and data frames. By doing so, the large interference problem can be effectively avoided, while retaining a high level of power efficiency. The feasibility and effectiveness of the proposed scheme had been validated by an analytic study on a simplified model and a series of simulations. As revealed in the simulation results, the proposed PCIA scheme outperforms conservative CTS reply (CCR) and IEEE 802.11 in many aspects, including data corruption ratio and power efficiency. Copyright © 2008 John Wiley & Sons, Ltd.

The TCP “Adaptive-Selection” Concept

The rapidly increasing importance of wireless communications (including satellite), together with the rapid growth of high speed networks, pose new challenges to transmission control protocol (TCP). Among them, the most prominent are long round trip times (RTTs), not negligible packet error rates (PER), and very large bandwidths. To overcome them, a wide variety of TCP enhancements has been presented in the literature with different purposes and capabilities. However, as most proposals aim to address different impairments, they result optimized for specific network environments. Therefore, given the increasing level of heterogeneity of present and future networks, the choice of ldquothe bestrdquo TCP enhancement seems a quite irresolvable problem, depending on the characteristics of the specific connections. The TCP adaptive-selection concept, presented and discussed in this paper, aims to circumvent this problem by providing an alternative approach that challenges at the root the idea that only one TCP enhancement must be adopted, not only on the whole network in general, but also on the same server machine. In fact, by extending the concept that underlies adaptive coding and modulation (ACM) to transport layer, TCP adaptive-selection envisages the concurrent adoption of different TCP versions on the same server, the better to match the different impairments present on different connections. The implication of this novel approach, as well as the possible criteria to be adopted for the TCP selection, are deeply discussed in this paper, where a particular emphasis is given to the ldquodynamicrdquo TCP adaptive-selection variant. Preliminary results, referring to a simple network topology, chosen to enlighten the mechanism of the TCP adaptive-selection technique, are also provided. They are quite encouraging and justify the following remarks on feasibility and the discussion of some implementation proposals.

ARLP: an adaptive link layer protocol to improve TCP performance over wireless fading channels

AbstractImproving the performance of Internet services is essential for future generation wireless networks. However, the correlated fading channels are found to be very unfriendly to transmission control protocol (TCP) performance in such networks. The variation in fading rate brings further challenge to wireless networks when supporting Internet applications, most of which run TCP as the transport layer protocol. In this paper, we first analytically study the performance of different radio link protocol (RLP) retransmission schemes in supporting TCP. In particular, we investigate the key quality of service (QoS) parameters of RLP such as average delay, delay variance and recovery rate of lost frames. Our analytical and simulation results show that a single retransmission scheme does not yield the best performance for different fading rates. To address this problem, we propose an adaptive radio link protocol (ARLP) that dynamically estimates the channel fading rate and also adaptively chooses those retransmission schemes that best fit the estimated fading rate. The performance of ARLP is evaluated in terms of response time (the time ARLP takes to respond to fading rate change), throughput improvement and energy consumption. The results show that ARLP can improve the performance of a particular mobile host as well as the total throughput of wireless networks, at the cost of a little extra energy consumption at low frame error rate. On the other hand, at high frame error rate, ARLP saves energy because of fewer retransmissions. Copyright © 2004 John Wiley & Sons, Ltd.

Grid-distributed visualizations using connectionless protocols

The NERSC and Lawrence Berkeley National Laboratory visualization group has developed the Visapult tool to attack grand challenge problems. Visapult is a distributed, parallel, volume rendering application that leverages parallel computation and high-performance networking resources that are on the same scale as the supercomputers generating the data. We've improved Visapult's effectiveness using aggressive network tuning and network protocol modifications. In particular, we used a new connectionless user datagram protocol (UDP) to improve network efficiency from a 25 to 88 percent line rate increase for multigigabit networks. This connectionless protocol also dramatically reduces the latency of network event delivery, improving the responsiveness of wide area distributed interactive graphics applications as compared to transmission control protocol (TCP) streams. We believe that this UDP protocol, as well as transport encodings and algorithms that can tolerate loss gracefully, will become a fundamental component of future grid visualization architectures.