Multipath TCP Research Articles

D-LIA: Dynamic congestion control algorithm for MPTCP

The congestion control algorithm (CCA) of Multipath TCP (MPTCP) mainly portrays​ two fundamental challenges to properly utilize the available bandwidth. First, MPTCP should provide an incentive over single-path TCP while not harming any existing single-path TCP flows when sharing the same bottleneck. Second, it should better utilize the paths by ensuring high throughput with low packet losses. We focus to improve the second goal by implementing a novel technique to dynamically control the decrease factor of the CCA depending on the interval between packet losses. We implemented it in Linux kernel and found a significant performance improvement by extensive the Mininet experiments.

System Reliability Assessment of a Fast Retransmit Through ${k}$ Separate Minimal Paths Under the Latency

A fast retransmit, which reduces the sender’s waiting time before retransmitting a lost segment, is applied to guarantee data integrity with no data loss in transmission. Based on fast retransmit, many application protocols have been enhanced and evolved to ensure quality of service and reduce data transmission time. One of application protocols is the multipath transmission control protocol which is catholically applied in modern computer networks. Communication lines used in this kind of network have different states, namely, failure, partial failure, and maintenance. Therefore, a computer network with a fast retransmit can be classified as stochastic and is called a stochastic-flow computer network with a fast retransmit (SCNFR). This paper assesses the system reliability of SCNFR for the successful transmission of demand d through ${k}$ ( ${k} \,\, >1$ ) separate minimal paths ( ${k}$ SMiP) under the latency. An algorithm is proposed to find all minimal capacity vectors (MCVs) that satisfy the demand and latency. Then, the system reliability is computed based on all MCVs. We adopt two practical cases of the pan-European research and education network and the Taiwan academic network to explore the effectiveness of the algorithm. The results show that the system reliability can be classified as decision reference while the manager decides the better ${k}$ SMiP with higher system reliability.

Shared Bottleneck-Based Congestion Control and Packet Scheduling for Multipath TCP

In order to be TCP-friendly, the original Multipath TCP (MPTCP) congestion control algorithm is always restricted to gain no better throughput than a traditional single-path TCP on the best path. However, it is unable to maximize the throughput over all available paths when they do not go through a shared bottleneck. Also, bottleneck fairness based solutions detect the bottleneck and conduct different congestion control algorithms at different bottleneck sets to increase throughput while remaining fair to single TCP. However, existing solutions generally detect shared bottlenecks through delay correlation and loss correlation between two flows, which often lead to misjudgement in dynamic and complex network scenarios. Therefore, in this paper, we first propose a new Shared Bottleneck based Congestion Control scheme, called SB-CC, which leverages ECN (Explicit Congestion Notification) mechanism to detect shared bottlenecks among subflows and estimate the congestion degree of each subflow. Then, with the congestion degree, SB-CC balances the loads among all subflows, and smooths out congestion window fluctuation. Also, in order to prevent throughput degradation due to out-of-order packets, we propose a Shared Bottleneck based Forward Prediction packet Scheduling scheme, called SB-FPS. SB-FPS distributes data according to the window size changes of each subflow, and thus could more accurately schedule data in shared bottleneck scenarios. We implement our proposed scheme in the Linux kernel and simulation platform to evaluate the performance in different scenarios. Measurement results indicate that our scheme can detect the bottleneck more accurately and improve the overall network performance while still keeping bottleneck fairness.

Design and Development of Efficient Multipath TCP using GMM clustering for Big Data in Public Cloud Data Center

Currently new topologies have been introduced in many data centers that provide location independence and larger aggregate bandwidth by making different multiple paths in the network core. This work proposes transport of data from TCP (Transmission control Protocol) to multi-path TCP (MPTCP) for maximum utilization of paths over network flow. In spite of its added advantages, some sort of work on MPTCP to be carried out on cloud environment and further, efficient way of using MPTCP on real-world cloud application still looks like unclear problem. Further, the work also concerned on MPTCP usage in most effective and feasible way for cloud and data center environments over various conditions on network. The experiment is conducted by clustering the public cloud data using Gaussian Mixture Model (GMM) based Expectation and Maximization (EM) algorithm and communicated over a network using MPTCP. The results shows that the proposed method yields high-speed data transfer and low communication delay when compare to traditional TCP technique.

ORCHESTRA: Supercharging Wireless Backhaul Networks Through Multi-technology Management

Today’s and tomorrow’s networks are becoming increasingly complex and heterogeneous with a large diversity of devices and technologies. To meet growing demand, and support client mobility there is need for intelligent mechanisms like multi-technology load balancing and handovers. Current solutions, like Multipath Transmission Control Protocol (MPTCP), fail to provide a fine-grained, coordinated, and transparent answer to this heterogeneity, while the lower layers of the Open Systems Interconnection stack simply ignore it by providing full separation of layers. Therefore, we introduce ORCHESTRA, a data link layer framework for the management of multi-technology networks and devices, enabling packet-level dynamic handovers, load balancing, and duplication across network technologies. The framework is the first of its kind in providing fine-grained packet-level control across different technologies in a network-wide manner. Moreover, it works on top of existing standards without the need for hardware changes. This is achieved through a fully transparent virtual Medium Access Control layer and a Software-Defined Networking controller with global intelligence. The framework is implemented in a prototype running on off-the-shelf hardware and we demonstrate its features across different IEEE 802.11 technologies and 4G (Long Term Evolution). We demonstrate that ORCHESTRA outperforms MPTCP and allows for real-time inter-technology handovers and that overall throughput and reliability are improved in wireless networks.

Redundancy and Diversity in Wireless Networks to Support Mobile Industrial Applications in Industry 4.0

Factories are evolving into fully digitalized and networked structures for more adaptive and agile production ecosystems in the context of the Industry 4.0. Wireless communications will be a technical pillar of this evolution as it improves the reconfigurability of factories and the integration of mobile robots and objects. The integration of industrial wireless networks into the Industry 4.0 requires solutions capable to support highly reliable and deterministic low latency communications. This is particularly challenging for mobile industrial applications with constantly changing link quality conditions. This article experimentally evaluates for the first time the capacity of diversity and redundancy to improve the reliability and latency of wireless networks for mobile industrial applications. To this aim, a prototype is built in a collaborative robotics experimental facility. The prototype wirelessly connects a dual-arm robot and a mobile robot that collects and supplies components to the dual-arm robot. The prototype implements redundancy and diversity (using multipath TCP) for the wireless connections between both robots. The conducted trials show that both techniques improve the reliability of mobile industrial wireless communications even under the presence of interference. However, redundancy achieves lower latency levels and represents then the most attractive solution to support mobile industrial applications.

A Memory-Efficient Transmission Scheme for Multi-Homed Internet-of-Things (IoT) Devices.

Internet-of-things (IoT) is a wide spreading technique that enables intelligence to the everyday objects, however, IoT devices are limited in computation and memory space due to their small physical sizes. As a result, IoT applications generally connect to the remote cloud that provides high computation and large storage. To enhance this communication, some IoT devices are equipped with multiple networks, e.g., cellular or Wi-Fi, by using Multipath TCP (MPTCP). However, MPTCP requires large buffer memory space compared to the legacy TCP, which is problematic for low-memory IoT devices. This paper proposes a new MPTCP scheme that leverages the multi-homed feature of low-memory IoT devices. Our design utilizes an application-level distributor that transmits packets to each MPTCP socket at each endpoint of the data. This scheme cleverly avoids the buffer blocking problem, while still maintaining the benefits of multi-homing. The main contribution of our paper is three-fold. First, our proposal achieves the benefits of multipath while avoiding buffer blocking due to out-of-order packets. Second, since our scheme utilizes the original MPTCP and modifies only the application level, it can be deployed more easily to the legacy systems. Finally, our experimental results, conducted on a Linux testbed and real-world cellular/Wi-Fi, show that the proposed scheme requires only half or less memory to achieve the performance of MPTCP.

Tuning high flow concurrency for MPTCP in data center networks

In the data center networks, multipath transmission control protocol(MPTCP) uses multiple subflows to balance traffic over parallel paths and achieve high throughput. Despite much recent progress in improving MPTCP performance in data center, how to adjust the number of subflows according to network status has remained elusive. In this paper, we reveal theoretically and empirically that controlling the number of concurrent subflows is very important in reducing flow completion time (FCT) under network dynamic. We further propose a novel design called MPTCP_OPN, which adaptively adjusts the number of concurrent subflows according to the real-time network state and flexibly shifts traffic from congested paths to mitigate the high tail latency. Experimental results show that MPTCP_OPN effectively reduces the timeout probability caused by full window loss and flow completion time by up to 50% compared with MPTCP protocol.

Multipath congestion control with network assistance

The use of multiple transport flows over distinct, if possible, paths, is a well-known technique for enhancing the performance and stability of data transfer. Multipath TCP (MPTCP), the most popular multipath transport protocol in-use, allows a single receiver to exploit multiple paths from a single sender. Nevertheless, MPTCP cannot fully exploit the potential gains of multipath connectivity, as it must fairly share resources with regular, single-path TCP, without knowing whether the available paths are distinct or share bottleneck links, due to IP’s design choices. We introduce a hybrid congestion control algorithm for multipath transport that enables higher bandwidth utilization compared to MPTCP, while remaining friendly to TCP-like flows. Our solution employs (i) Normalized Multiflow Congestion Control (NMCC), a novel end-to-end congestion control algorithm and (ii) an in-network module that exposes routing information to the end-users in order to support the greedy friendliness technique. The end-to-end NMCC is architecture-independent and can be seamlessly integrated with MPTCP. The in-network module has been implemented for the PSI Information-Centric Networking architecture, but it can also be integrated with Multi-Protocol Label Switching (MPLS) and Software Defined Networking (SDN). Using an actual protocol implementation deployed on our testbed, as well as on a comprehensive packet-level simulator, we obtain experimental results which demonstrate clear gains for our design in terms of throughput and friendliness to other flows.

Packet Scheduling in Multipath TCP: Fundamentals, Lessons, and Opportunities

Multipath transmission control protocol (MPTCP) is a transport protocol that allows the simultaneous use of multiple transmission control protocol subflows across the existing IP addresses between peers. Since each subflow undergoes the bottleneck link condition of its path, selecting the best subflow to schedule an outgoing packet plays a key role in the multipath performance. While good scheduling decisions can significantly improve throughput, wrong decisions prevent users from benefiting the aggregating capacities of available subflows. To deal with this concern, in the last years, several scheduling solutions were proposed to achieve different goals and applications. Different from other surveys and tutorials, in this article, we provide a tutorial of packet scheduling in the MPTCP that brings not only its fundamentals but also a detailed analysis of multipath performance from a consistent experimental methodology. In a multipath network setup, we compare single-criterion and multicriteria schedulers under different bottleneck conditions and multipath congestion controls. From a comprehensive experimental analysis that unveils several performance issues, we discuss the lessons learned and research opportunities regarding the multipath throughput improvement as the central motivation. In this way, this article provides a comprehensive analysis of packet scheduling in the MPTCP, not only in theory but in practice as well.

Multipath transmission control protocol–based multi-access traffic steering solution for 5G multimedia-centric network: Design and testbed system implementation

Various technologies have been developed for the efficient use of the multiple radio access technologies resource at the radio access network level or other network levels to improve user service quality in mobile communication networks. In long-term evolution, mobile carriers are commercializing radio access network-level traffic aggregation technologies such as licensed-assisted access-long-term evolution, long-term evolution-unlicensed, and long-term evolution-wireless local area network aggregation, which use the multi-accesses of the 3rd Generation Partnership Project and WiFi, and the multipath transmission control protocol–based traffic aggregation technologies at the L3 network level. The standardization of 3rd Generation Partnership Project Release 16, which is scheduled to be completed by 2020, is under progress to support the traffic aggregation technology at the L3 network level through a multi-access 5G network. Multipath transmission control protocol is also considered as a traffic aggregation technology. However, it is difficult to apply the multipath transmission control protocol employment model used in long-term evolution to the 5G network structure as it is due to the change to a common core architecture that accommodates multiple radio access technologies through one common interface. Therefore, this article proposes an optimal 5G system architecture and a multipath transmission control protocol adaptation method to support the access traffic steering function based on multipath transmission control protocol in a 3rd Generation Partnership Project 5G mobile communication network. We have verified the development of the multipath transmission control protocol–based multi-access traffic steering technology by implementing the proposed solution in a commercial server on a testbed based on the 5G system standard of 3rd Generation Partnership Project Release 15. Furthermore, this article defines problems that occur when implementing the multipath transmission control protocol–based multi-access traffic steering system and proposes relevant solutions. Based on the implementation results, it is demonstrated that the proposed multipath transmission control protocol–based multi-access traffic steering system can perform traffic steering in the 3rd Generation Partnership Project 5G network.

Discrete-Time Sliding-Mode Controllers for MPTCP Networks

TCP provides the principal framework for the Internet traffic control. Following the protocol development, however, the communicating parties have not benefitted from the potential of multiple interfaces, now commonly installed at the end-point devices. In order to grasp new opportunities, a multipath version of TCP - multipath TCP (MPTCP) - has recently been introduced. It permits the simultaneous use of a few, diverse interfaces for enhancing the user experience. This article provides a discrete-time model of the data exchange process in the MPTCP framework and new flow control algorithms. The algorithms, applicable to the paths with nonhomogenous properties with respect to delays, loss rate, etc., are designed following the rules of discrete sliding-mode control (DSMC). As a result, direct implementation in discrete networking context and robust transmission system performance are guaranteed in uncertain operating conditions. It is formally demonstrated that a finite data queue length in the end-point buffers and a feasible (non-negative and bounded) input signal are ensured despite input and output perturbations affecting the control process. It is also shown that the classical DSMC design approach results in decreased performance for unanticipated surge in the intensity of network-related perturbations. A second, improved algorithm, with a well-chosen sliding variable, eliminates this drawback.

Towards Adaptive Multipath Managing: A Lightweight Path Management Mechanism to Aid Multihomed Mobile Computing Devices

With the large scale deployment of multihomed mobile computing devices in today’s Internet, the Multipath TCP (MPTCP) is being considered as a preferred data transmission technology in the future Internet due to its promising features of bandwidth aggregation and multipath transmission. However, MPTCP is more likely to be vulnerable to the transmission quality differences of multiple paths, which cause a “hot-potato” out-of-order arrival of packets at the receiver side, and in the absence of a related approach to fix this issue, serious application level performance degradations will occur. In this paper, we proposes MPTCP-LM 3 , a Lightweight path Management Mechanism to aid Multihomed MPTCP based mobile computing devices towards efficient multipath data transmission. The goals of MPTCP-LM 3 are: (i) to offer MPTCP a promising path management mechanism, (ii) to reduce out-of-order data reception and protect against receiver buffer blocking, and (iii) to increase the throughput of mobile computing devices in a multihomed wireless environment. Simulations show that MPTCP-LM 3 outperforms the current MPTCP schemes in terms of performance and quality of service.

Coupled Multipath BBR (C-MPBBR): A Efficient Congestion Control Algorithm for Multipath TCP

Multipath transmission control protocol (MPTCP) is a promising transport layer protocol that enables a device to utilize multiple communication interfaces simultaneously, thereby achieving high throughput. A congestion control algorithm (CCA) employed in MPTCP constitutes a key part that controls the data flow through different subflows (SFs). There are two fundamental challenges associated with MPTCP CCAs. First, MPTCP flows should have an advantage over single-path flows; second, MPTCP flows should be fair, indicating that SFs sharing a common bottleneck should occupy a capacity fairly close to that occupied by a single-path flow. Several MPTCP CCAs have been developed; however, they have failed to satisfy these challenges in all scenarios. Recently, Google has introduced the bottleneck bandwidth and round-trip-time (BBR), a new CCA for single-path TCP, achieving high throughput with minimum delay by employing a network model. In the present paper, we propose a novel MPTCP CCA based on BBR named coupled multipath BBR (C-MPBBR) that satisfies the fundamental challenges by exploiting the concept of network modeling in BBR. C-MPBBR addresses the first challenge by closing the low-bandwidth SFs by tracking the delivery rate and bottleneck bandwidth (BtlBW). Then, it satisfies the second challenge through identifying those SFs that share a common bottleneck and dividing the BtlBW share corresponding to a SF among them. We implemented C-MPBBR in the Linux kernel, tested it on a wide range of scenarios by the Mininet emulation experiments, and the real-world Internet, and confirmed that the proposed C-MPBBR outperforms the existing MPTCP CCAs in terms of successfully satisfying the fundamental challenges by ensuring both throughput and fairness.

Can Multipath TCP be Robust to Cyber Attacks With Incomplete Information?

Promoted by the advancements in the various wireless access technologies, modern mobile devices equipped with multiple network interfaces are rapidly becoming the norm, and this provides a driving force for the large-scale deployment of the Multipath Transmission Control Protocol (MPTCP) in the current and future Internet. However, the simultaneous use of multiple network paths for concurrent multipath data transmission can make MPTCP have a larger attack surface than the traditional single-path transport protocols, and this may be likely to pose a risk of MPTCP being much more susceptible to cyber attacks. In this paper, we present a measurement method to investigate the vulnerability and robustness of MPTCP under cyber attacks with incomplete network information, by considering the fact that most cyber attacks normally lack of real-time information with respect to various MPTCP attributes. We mathematically characterize cyber attacks with incomplete network information from the viewpoints of both the cyber attacker and the MPTCP communication system, and then we introduce a mixed attack strategy, by jointly considering the features of both the random attacks and the selective attacks, to evaluate the robustness of MPTCP.

Analysis of Congestion Control for Multipath Transmission Control Protocol: Challenges and Solutions

Multipath Transmission Control Protocol has turned into an intriguing matter in today’s protocol stack. With the development of rising technologies, it is the most noteworthy expansion of Transmission Control Protocol. A cell phone normally supports both a 2G/3G/4G connectivity and a wireless connectivity. Limitation of Transmission Control Protocol particularly in a mobile environment is that it does not handle mobility very well. Multipath Transmission Control Protocol resolves the shortcomings of Transmission Control Protocol. It allows multihoming simultaneously. Here multiple network links act as a single link and a single stream of data is divided into subflows across multiple networking paths. This has clear advantages for reliability and it can prompt more productive utilization of networking resources. But Multipath Transmission Control Protocol is far away from being a flawless protocol. The significant issues are the congestion control and the reordering of the packet at the destination. Congestion control and packet reordering in this protocol have been very complex so far but if it’s not considered, it can radically influence the throughput for the protocol. Therefore, in this work, we will find various problems for congestion control and packet reordering techniques in Multipath Transmission Control Protocol and also, we will discuss possible solutions for these problems.

MPWiFi: Synergizing MPTCP Based Simultaneous Multipath Access and WiFi Network Performance

Multipath TCP (MPTCP) enables a client to exploit multiple wireless paths simultaneously for improved throughput and mobility resilience. However, MPTCP clients in WiFi networks may easily lower the achievable throughput of the network due to excessively created connections over access points (APs), particularly those that own a weak link quality. This is caused by the fact that the maximal achievable throughput of a WiFi AP can be easily affected by the number of connections accessing it and the link qualities of those connections. In this paper, we first verify such effects through extensive experiments and analysis. We then propose a novel scheme, denoted MPWiFi, to solve this issue while keeping the benefits of MPTCP based multipath access in WiFi networks. Our scheme allows a MPTCP client to obtain resources on its best WiFi path freely and suppresses its subflows in additional paths when congestion happens. As a result, the degrading to the WiFi AP's achievable throughput is greatly prevented with acceptable influences on the benefits of MPTCP clients (i.e., their multipath access is intervened only on congested non-best APs). The fairness to MPTCP clients is also guaranteed through their best WiFi connection. The proposed solution is implemented along with the Linux Kernel MPTCP implementation. Extensive real-world deployment based experiments and NS3 simulation show that the proposed scheme can effectively alleviate the adverse impact of MPTCP based multipath access in WiFi networks while keeping its benefits.

QSOCKS: 0-RTT Proxification Design of SOCKS Protocol for QUIC

Multipath TCP (MPTCP) is an evolution of TCP, capable of using multiple network paths to enhance resilience to network handovers. However, Server-side modification is the key challenge for deployment of MPTCP on a large scale. Therefore, a proxy-based design that uses SOCKSv5 over MPTCP was proposed. Though MPTCP enhances the download experience, it also impacts the browsing experience and Page Loading Time (PLT) due to additional SOCKSv5 protocol signaling overhead. On the other hand, to improve the performance of TCP, Google proposed QUIC (Quick UDP Internet Connection), which addresses the network handover resilience. QUIC also faces server modification as a major challenge. In this article, we propose a novel design of SOCKS over QUIC (QSOCKS), which improves browsing experience while enhancing reliability. QSOCKS ensures 0RTT/1RTT connection time, thereby improving the Page Loading Time (PLT) and Video Loading Time (VLT). We evaluated the performance of QSOCKS through live experiments on the top websites of various web properties located in different regions, using Samsung S9 smartphones. Moreover, we evaluated our proposal for file download scenario in both homogeneous and heterogeneous Wi-Fi & cellular environment. The users not only benefit from the inherent advantages of QUIC but are also privileged with a better browsing experience.

Multipath Routing and MPTCP-Based Data Delivery Over Manets

In some special circumstances (e.g., tsunamis, battlefields, and earthquakes), communication infrastructures are damaged or nonexistent. For communication among people, mobile smart devices (MSDs) can be used to construct mobile ad hoc networks (MANETs). This paper focuses on the problem of data delivery in MANETs aiming to improve the quality of service (QoS) and quality of experience (QoE) users receive. MANETs, however, have the well-known problems of frequent disconnections and high rates of failed transmissions as MSDs move in and out of network coverage areas, and the topology constantly changes. To solve these issues, the main contributions of this work are as follows: (1) we provide and investigate the QoE-driven multipath TCP (MPTCP)-based data delivery model in MANETs; (2) we present hidden Markov model-based optimal-start multipath routing, which can effectively predict a mobile node's near future network connection state according to its past connection state; (3) we leverage MPTCP to simultaneously transmit data via multiple interfaces of MSDs and improve the establishment method for MPTCP subpaths; and (4) we study and improve the algorithm of multihop routing in MANETs. The test results show that our algorithms can offer more efficient use of multiple subpaths and better network traffic load balancing than using standard MPTCP alone.

Optimized Preference-Aware Multi-Path Video Streaming with Scalable Video Coding

Most client hosts are equipped with multiple network interfaces (e.g., WiFi and cellular networks). Simultaneous access of multiple interfaces can significantly improve the users’ quality of experience (QoE) in video streaming. An intuitive approach to achieve it is to use Multi-path TCP (MPTCP). However, the deployment of MPTCP, especially with link preference, requires OS kernel update at both the client and server side, and a vast amount of commercial content providers do not support MPTCP. Thus, in this paper, we realize a multi-path video streaming algorithm in the application layer instead, by considering Scalable Video Coding (SVC), where each layer of every chunk can be fetched from only one of the orthogonal paths. We formulate the quality decisions of video chunks subject to the available bandwidth of the different paths, chunk deadlines, and link preferences as an optimization problem. The objective is to to optimize a QoE metric that maintains a tradeoff between maximizing the playback rate of every chunk and ensuring fairness among chunks. The proposed metric prefers to use bandwidth of the links to optimize a concave utility function of the chunk quality. Even though the formulation is a non-convex discrete optimization, we provide a quadratic complexity algorithm which is shown to be optimal in some special cases. We further propose an online algorithm where several challenges including bandwidth prediction errors, are addressed. Extensive emulated experiments in a real testbed with real traces of public dataset reveal the robustness of our scheme and demonstrate its significant performance improvement compared to other multi-path algorithms.