Reliable TCP Research Articles

Novel Approach for Network Data Exchange Among Safety-Related Control Systems of Nuclear Reactors

Industrially mature digital networking technologies form the backbone of the distributed control architectures of nuclear reactors. Typically, hundreds of control systems responsible for assuring safer and secure plant operations are located in the field and interconnected via wired isolated local area networks, which are also connected to centralized servers and operating consoles located in the main control room. Many of such control systems require data processed by other systems situated far away in the plant, which mandates multiple concurrent reliable TCP sessions to be active or live for such field-level control systems. Multi-socket communication beyond 10 is practically difficult for embedded systems with limited memory and processing capabilities; hence, data accumulation, extraction, and routing are typically done with the help of commercially available high-performance servers and switches. The servers and operating consoles of a plant are generally Linux-based commercial-off-the-shelf (COTS) industrial computers, whose development lifecycle is not accessible for review and in accordance with safety guides; hence, qualifying such components for safety operations is extremely difficult. This paper presents a novel way of independently offloading safety-related data transactions from such COTS components (reducing dependency) with the help of very simple, reliable, and secure hardware, which is referred to as a data exchange and processing unit (DEPU). An approach is proposed to realize distributed control architecture with this proposed hardware (to simplify qualification tasks) along with existing servers and operating consoles without compromising powerful and convenient human-machine interface as well as the data logging capabilities of such components. Hardware and software design perspectives, performance characterization, and qualification testing of the DEPU in accordance with nuclear power plant instrumentation and control system design guidelines are also briefed in this paper.

Experimental study of QoE improvements towards adaptive HD video streaming using flexible dual TCP-UDP streaming protocol

The Flexible Dual TCP-UDP Streaming Protocol (FDSP) combines the reliability of TCP with the low latency of UDP, thus providing transport layer improvements towards maintaining high QoE of multi-bitrate videos in adaptive streaming. FDSP delivers the more critical parts of the video data via TCP and the rest via UDP. FDSP also uses Bitstream Prioritization (BP), a sliding scale that determines the proportion of video data that is sent using TCP. BP can be adjusted according to the level of network congestion. FDSP-based streaming reduces total rebuffering time by over 90%, and rebuffering instances by 50% in many cases compared to TCP-based streaming. At the same time, packet loss reduces by over 75% for most BP levels compared to UDP-based streaming. In addition, FDSP-based streaming is potentially more suitable for adaptive streaming compared to the state-of-the-art TCP-based HTTP Adaptive Streaming (HAS), which is often plagued by high latency and high bandwidth requirements. In contrast, FDSP requires significantly less bandwidth than TCP in congested networks while exhibiting more stable client buffers.

Understanding the Security Implication of Aborting Virtual Machine Live Migration

Live migration of Virtual machines (VMs) has become a regular tool for edge and cloud operators to facilitate system maintenance, fault tolerance, and load balancing, with little impact on running instances. However, the potential security risks of live migration of VMs are still obscure. In this article, we expose a new vulnerability in the existing VM live migration approaches, especially the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">post-copy</i> approach. The entire live migration mechanism relies upon reliable TCP connectivity for the transfer of the VM state. We demonstrate that, if the host server is vulnerable to off-path TCP attacks, the loss of TCP reliability leads to VM live migration failure. We demonstrate that, by intentionally aborting the TCP connection, attackers can cause unrecoverable memory inconsistency for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">post-copy</i> , leading to a significant increase in downtime and performance degradation of the running VM. Additionally, we present detailed techniques to reset the migration connection under heavy networking traffic. We also propose effective defenses to secure the VM live migration. Our experimental results demonstrate that memory inconsistencies could be devastating to some applications, and it only takes a few minutes to reset a heavy migration connection.

Extensive evaluation on the performance and behaviour of TCP congestion control protocols under varied network scenarios

In recent decades, many TCP Congestion Control (CC) protocols have been proposed to improve the performance and reliability of TCP in various network scenarios. However, CC protocols are usually closely coupled with network conditions such as latency and packet loss. Considering that networks with different properties are common, e.g., wired/wireless LAN and Long Fat Networks (LFNs), investigating both performance and behaviors of CC protocols under varied network scenarios becomes crucial for both network management and development. In this paper, we conduct a comprehensive measurement study on the goodput, RTT, retransmission, friendliness, fairness, convergence time and stability of most widely-used CC protocols over wired LAN/WAN and wireless LAN (both 2.4GHz and 5GHz Wi-Fi). We also conduct comparative studies with respect to transmission cost, congested reverse path and bottleneck queue size in network simulator.Based on our analysis, we reveal several interesting and original observations. We found that the goodput of BBR is at least 22.5% lower than other CC protocols in wireless LAN due to insufficient pacing rate, even though it can always fully utilize the bottleneck bandwidth with low RTT in wired networks. We also observed that the total on-wire data volume of BBR is higher than CUBIC (e.g., 2.37% higher when RTT = 100ms and loss rate = 0.01%). In addition, BBR can fully utilize the bottleneck bandwidth in most queue sizes ( ≥ 20packets). Surprisingly, we noticed that as the default CC protocol in most modern operating systems, CUBIC is too aggressive and unfriendly in both LAN and wireless LAN, greatly suppressing the goodput of other competing CC protocols. More specifically for CUBIC in wireless LAN, it generates 129% more retransmissions than other CC protocols. Nevertheless, we have also seen that, in scenario with heavily-congested reverse path, CUBIC can provide full utilization on bottleneck bandwidth. Lastly, we also observed that BBR converges very quickly in all evaluated scenarios, while other CC protocols present varied results, e.g., Westwood+ and Veno converge faster in 5GHz Wi-Fi networks than 2.4GHz networks.

Multi-channel transmission method for improving TCP reliability and transmission efficiency in UNIWAY

In ubiquitous computing environment, data is collected by a number of devices and transmitted to a central server which is trusted to provide the information to the user. In order to cope with security threats targeting the central service providing system, there is a growing trend to use unidirectional data transmission gateway to completely block the possibility of intrusion of an external network and an internal network. There is a difficulty in that a physical unidirectional data transmission gateway up to now can use only a single session and does not support a private protocol. In this paper, we propose transmission control protocol based service which is a constraint in unidirectional security gateway system was being available, and unidirectional security gateway using multi-channel transmission method for transmission efficiency in multi-proxy operation and transmission control protocol’s reliability and enhance transmission efficiency of the unidirectional security gateway and shows the experimental results of proposed method.

Cross-layer-based adaptive congestion and contention controls for accessing cloud services in 5G IEEE 802.11 family wireless networks

The big-data cloud services accessed through 4G LTE-A and 5G WiFi networks need extremely high-speed and highly reliable transmission. However, it exhibits a critical issue that of inconsistently executing congestion control for the global end-to-end connection and contention control for the local wired/wireless links. For instance, in the transport layer (Layer 4 or L4), the reliable TCP adopts ACK-based congestion control to determine the congestion window (denoted by L4_CWND) for the global E2E connection; but, the link layer (Layer 2 or L2) adopts the Truncated Binary Exponential-based (TBE) access control to determine the contention window (denoted by L2_CW) for the local wireless link. Clearly, the congestion and contention control mechanisms for the global end-to-end connection and the local wireless link should cooperate tightly and consistently, but the existing congestion control and contention control are separately operated at different layers. This paper thus proposes a Cross-layer-based Adaptive Congestion Control (namely CACC) for the connection-based transport layer and the link-based media access layer. CACC aims to determine L4_CWND for the end-to-end congestion control, and then sends the cross-layer L4 congestion state to L2 to determine L2_CW_Max and L2_CW consistently. Numerical results demonstrate that CACC outperforms the compared approaches in L2 goodput, L2 collision probability, L2 contention delay, L2 fairness, L4 goodput, L4 fairness, and L4_friendliness. Furthermore, the claims of the determined L4_CWND and L2_CW are supported by mathematical analyses.

TCP based-user control for adaptive video streaming

Nowadays, Media streaming services over TCP have become very popular because of the TCP's reliability, which provides remarkable stability to the Internet. However, in order to offer a high media quality and a good user satisfaction, the media streaming service requires that transport protocols can be adapted continuously with the network parameters. However, the diversity, of terminals (i.e., tablet, smart phones, laptop ź etc.) and their corresponding capabilities, means that users' agnostic solutions are inefficient to cope with such diverse contexts. Indeed, the intrinsic characteristics and parameters of the terminal users (i.e., devices) need to be taken into account on the video streaming adaptation process. The classic adaptive video streaming services do not consider the user parameters on the adaptation process. In this paper, we propose an adaptive video streaming solution to improve the user satisfaction factor by adapting the TCP parameters according to the user's parameters on mobile networks. The user satisfaction factor is calculated according to some metrics driven from the user's quality of experience (QoE). The work is validated through our proposal based on a new mobile agent (which does all the work) developed on a Linux script platform and tested on different kinds of devices with different scenarios.

Improving TCP Throughput Using Modified Packet Reordering Technique (MPRT) Over Manets

at the beginning of development of network technology TCP transport agent were designed assuming that communication is using wired network, but recently there is huge demand and use of wireless networks for communication. Those TCP variants which are successful in wired networks are neither able to detect exact causes of packet losses nor unnecessary transmission delays over wireless networks. The biggest challenge over MANET is design of robust and reliable TCP variant which should give best performance in different network scenarios. Till date more than dozens of TCP variants designed and modified by researcher and scientist communities even though the level of TCP performance have to be optimum in different scenarios, Such as congestion, link failure, signal loss and interferences. Over rod, grid and bulk network model also. As some of TCP-variant performs well in particular network scenarios but degrades in other scenarios. The objective of this research work, to modify packet reordering technique based TCP variant, implement and compare its performance with other variants. Validation of basic and main network model done using network simulator (NS2) and calculated throughput, delay and packet drop by processing trace files. The simulated result shows that, proposed technique performs outstanding almost in all network scenarios with minimum packet losses and minimum delay.

A Robust Analytical Model of Mobile IP Handoff with Multiple Traffic Profiles

Mobile IP has been developed to provide the continuous information network access to mobile users. The performance of Mobile IP mobility management scheme is dependent on traffic characteristics and user mobility. Consequently, it is important to assess this performance in-depth through these factors. This paper introduces a novel analytical model of handoff management in mobile IP networks. The proposed model focuses on the effect the traffic types and their frame error rates on the handoff latency. It is derived based on general distribution of both successful transmission attempts and the residence time to be applicable in all cases of traffic characteristics and user mobility. The impact of the behavior of wireless connection, cell residence time, probability distribution of transmission time and the handoff time is investigated. Numerical results are obtained and presented for both TCP and UDP traffics. As expected, the reliability of TCP leads to higher handoff latency than UDP traffic. It is shown that, higher values of FER increase the probability of erroneous packet transfer across the link layer. A short retransmission time leads to end the connection most likely in the existing FA; however a long retransmission time leads to a large delivery time. The proposed model is robust in the sense that it covers the impact of all the effective parameters and can be easily extended to any distribution.

A Power-Saving Network Architecture for Accessing the Internet from Mobile Computers: Design, Implementation and Measurements

In this paper we propose a power-saving strategy for accessing the Internet from a mobile computer. Firstly, we measure the power consumption of a mobile computer that uses a TCP connection to send/receive data from the Internet. These measurements indicate that, by adopting TCP, the power consumption is negatively affected by the congestion in the fixed network. To solve this problem we extend the Indirect TCP model to achieve both the TCP reliability and an optimal power consumption level. To test our claim we design and implement a Power-Saving Network Architecture based on an enhanced indirect TCP model. Experimental results show that our approach is a promising development, with respect to the classical TCP approach, to reduce power consumption. Specifically, in our experiments the power consumption, by exploiting the enhanced indirect model, is significantly lower than the power consumption measured when using the legacy TCP approach.