A path characteristics based adaptive subflow switching algorithm for dynamic heterogeneous MPTCP network

Today's laptops and mobile terminals are equipped with several network interfaces belonging to different access technologies. Users can benefit from multi-homing to access network services anywhere, at any time and from any network. Multipath TCP (MPTCP) is a modified version of Transmission Control Protocol (TCP) which allows a TCP connection to simultaneously send data over multiple paths. One of the objectives of MPTCP is to improve the throughput of TCP connection. A MPTCP connection over multiple paths should achieve a no worse throughput than a single TCP connection over the best constituent path. In this paper, we evaluate the performance of MPTCP in terms of throughput optimization and load sharing. The measurements show that the context of heterogeneous networks (Ethernet, Wifi and 3G) has a great impact on the MPTCP performances and reveal the need of an intelligent algorithm for interface selection in MPTCP.

Recent data centers provide dense inter-connectivity between each pair of servers through multiple paths. These data centers offer high aggregate bandwidth and robustness by using multiple paths simultaneously. Multipath TCP (MPTCP) protocol is developed for improving throughput, fairly sharing network link capacity and providing robustness during path failure by utilizing multiple paths over multi-homed data center networks. Running MPTCP protocol for latency-sensitive rack-local short flows with many-to-one communication pattern at the access layer of multi-homed data center networks creates MPTCP incast problem. In this paper, Balanced Multipath TCP (BMPTCP) protocol is proposed to mitigate MPTCP incast problem in multi-homed data center networks. BMPTCP is a window-based congestion control protocol that prevents constant growth of each worker’s subflow congestion window size. BMPTCP computes identical congestion window size for all concurrent subflows by considering bottleneck Top of Rack (ToR) switch buffer size and increasing count of concurrently transmitting workers. This helps BMPTCP to avoid timeout events due to full window loss at ToR switch. Based on current congestion situation at ToR switches, BMPTCP adjust transmission rates of each worker’s subflow so that total amount of data transmitted by all concurrent subflows does not overflow bottleneck ToR switch buffer. Simulation results show that BMPTCP effectively alleviates MPTCP incast. It improves goodput, reduces flow completion time as compared to existing MPTCP and EW-MPTCP protocols.

Multipath TCP (MPTCP) is a promising technique for boosting application throughput while using well-known and versatile network socket interfaces. Recently, many interesting applications of MPTCP in various environments such as wireless networks and data centers have been proposed, but little work has been done to investigate the impact of this protocol on conventional network devices. For example, MPTCP throughput advantage can be better achieved if all MPTCP subflows are routed on disjoint paths, but this is currently not feasible since routers are not designed to recognize the membership of MPTCP subflows. In this paper, we take a first step to address this issue by proposing SAMPO, an online algorithm to detect and associate MPTCP subflows in network. The main challenge is that sampling techniques and network dynamics may cause a network device to only obtain partial flow records. SAMPO takes advantage of both protocol information and statistical characteristics of MPTCP data sequence number to overcome the challenge in network. Through analysis and experimentation, we show that SAMPO is able to detect and associate MPTCP subflows with high accuracy even when a small portion of the entire flow records are available.

TCP was originally designed for single session, thus could not utilize resources of multiple paths. MPTCP (Multipath TCP) provides enhanced performance and reliability by using multiple paths simultaneously at the Transport layer. But, LIA based congestion control of basic MPTCP does not show good performance when characteristics of two path are asymmetrical in the aspects of bandwidth in high-speed networks. In this paper, we suggest new MPTCP control scheme by applying TCP CUBIC on the high-speed path and modified LIA on the other low-speed data path. Our proposed scheme can enhance performance of high-speed asymmetric path more than 4 times compared to the basic MPTCP protocol.

Multipath Transmission Control Protocol (MPTCP) is an approach towards high-throughput and efficient load balancing over multiple paths. Each of paths forms a TCP connection with an IP address, and those can be implemented as multiple network interfaces or multiple ports within a network interface. In this paper, we focus on the multiple network interfaces environment. Each network interface with an IP address is called as a subflow. A subflow is a TCP connection which can have a different internet path identified by IP addresses of source and destination network interfaces. To control these multiple subflows, MPTCP supports many options. Specifically, to establish a new subflow, MPTCP uses an <monospace>ADD&#x005F;ADDR</monospace> option. A host sends <monospace>ADD&#x005F;ADDR</monospace> option to inform another host of its IP address, and then, the host receiving <monospace>ADD&#x005F;ADDR</monospace> option tries to establish a subflow at the address of <monospace>ADD&#x005F;ADDR</monospace> option. However, by forging the <monospace>ADD&#x005F;ADDR</monospace> option, an attacker can create a fake subflow that passes through itself and eventually hijack the connection between both end hosts. In a previous study, Hash-based Message Authentication (HMAC) was added to the <monospace>ADD&#x005F;ADDR</monospace> option, preventing it from being forged. Nevertheless, since the keys for generating HMAC can be leaked during three-way handshake, a variant of the <monospace>ADD&#x005F;ADDR</monospace> attack called the persistent <monospace>ADD&#x005F;ADDR</monospace> attack can be possible. To this end, we propose a protocol that can prevent the <monospace>ADD&#x005F;ADDR</monospace> attacks by backward confirmation of the <monospace>ADD&#x005F;ADDR</monospace> option without encryption. The main idea of our proposal is to apply a digital signature scheme for the backward confirmation. We show security analysis for the proposed protocol and compare with the previous studies in terms of time/space overheads.

Multipath Transmission Control Protocol (MPTCP) promises higher bandwidth and higher resilience against network path failures as an evolving technology for the future Internet. MPTCP allows multiple paths between two devices to be pooled and appear to the application as a single end-to-end transport connection. In this paper, we propose a solution for the packet reordering problem, to improve path utilization and aggregate throughput. The proposed method maintains the congestion window size when three duplicate acknowledgements occur to avoid unnecessary reductions in transmission rate. We evaluate the performance of the proposed solution using an NS-3 in different wireless scenarios and compare it against the performance of other existing reordering methods. The results show that the proposed method improves the aggregate throughput and path utilization when the packet drop rate is high.

One of the main goals of multipath TCP (MPTCP) is to achieve higher throughput than regular TCP by utilizing multiple paths simultaneously. When these paths share a common bottleneck, MPTCP tries not to be more aggressive than a regular TCP flow. This is achieved by MPTCP's coupled congestion control mechanism that couples the increase factor of MPTCP's subflows in congestion avoidance. However, slow-start remains unchanged and behaves uncoupled for each subflow, affecting MPTCP and concurrent traffic at the bottleneck. We propose LISA, a simple algorithm for coupling MPTCP subflows in slow-start, and investigate the trade-off that this coupling entails. Our evaluations show that coupling in slow-start not only provides gains for MPTCP but also for a concurrent TCP at the bottleneck.

Network functions virtualization (NFV) offers an alternative way to design, deploy, and manage networking services. This paper presents the implementation and deployment of a virtualized network function to solve MP-TCP’ shared bottlenecks problem. MP-TCP (MultiPath-TCP) is a protocol that allows hosts that have several interfaces to send data through multiple paths in the network. An MP-TCP connection is divided into several TCP connections called subflows that may follow different paths, in this way effective connection rates and resilience can be increased. However, in a scenario where MP-TCP is used with hosts having a single network interface, created subflows follow the same path even if several are available; this generates the problem known as a shared bottleneck. A solution to this problem is implemented as a SDN (Software Defined Networking) module that is integrated into OpenDayLight’s framework which is used as the SDN controller. This solution is then deployed as a NFV over a cloud infrastructure implemented with OpenStack over a high-end physical server. The deployment of the NFV is automated to a certain degree using Ansible, a DevOps tool. Finally, results of the tests of the SDN solution to MP-TCP’s shared bottlenecks and its operation as a NFV using a completely virtualized network are reported.

Multipath TCP (MPTCP) is a major extension of TCP that aims to offer higher aggregate bandwidth and robustness by pooling multiple paths within one transport connection. One of the current weaknesses of the protocol is the Delayed ACK scheme inherited from TCP. The Delayed ACK is an option of TCP that allows the receiver to delay sending an ACK for every other packet within a window given by the Delayed ACK timer. At the sender, the RTO should be no less than the Minimum RTO to avoid spurious timeouts. This strategy can lead to significant performance degradation in the presence of timeouts, especially in high speed networks, where RTT is usually one- or two-order of magnitude smaller than the Minimum RTO. When a subflow occurs a timeout, the receiver has to buffer data from all the subflows until the missing packet is received. The data may overrun the receive buffer to cause flow control at the sender, which seriously impacts the overall performance. In order to avoid MPTCP performance degradation, we propose a new Delayed ACK aiming to remove the Minimum RTO constraint at the sender while to reserve the Delayed ACK function at the receiver. Our solution requires only minor modification to the legacy Delayed ACK scheme and it introduces negligible computational overhead and no extra traffic overhead. We use a NS-3 network simulator to evaluate the performance of our new Delayed ACK in three typical network environments. The results indicate that MPTCP using new Delayed ACK scheme requires much smaller aggregate buffer than MPTCP using the legacy Delayed ACK scheme, especially in high speed networks where the buffer requirement reduces one- or two-order of magnitude.

With increasing deployment of Multipath TCP (MPTCP) in multihoming and data enter scenarios, there is a need to understand how its performance is affected in practice-both by traditional factors such as RTT measurements, and by new multipath-specific considerations such as sub flow selection. We carried out an initial but comprehensive study using an actual MPTCP implementation in an emulated network environment, to explore the impact of different factors on MPTCP throughput. We find that path selection and packet scheduling have a large effect on performance, and that merely trusting the congestion control mechanism to do the right thing is not enough. Moreover, we provide evidence that throughput can be improved by slight modifications to the send buffers and path selection components of the implementation. Important challenges in network design remain, if only to ensure that multiple suitable paths exist in a network.

The number of mobile terminals that have both a cellular interface and a Wi-Fi interface has been growing in the recent years. Meanwhile, Multipath TCP (MPTCP) that enables the simultaneous use of multiple paths with multiple TCP flows while showing just one regular TCP connection with the application has been standardized by the IETF and has drawn more attention recently. One feature of MPTCP is that it can be realized only by operating system layers supporting multipath communication without any modifications of the application. However, it might be difficult to install MPTCP in all server operating systems. In this paper, we propose a method for applying a proxy that forwards TCP communication from a server to MPTCP communication on a mobile core network, and show the results of evaluation with the existing equipment.

Multipath TCP (MPTCP) is the most significant extension of TCP that enables transmission via multiple paths concurrently to improve the resource usage and throughput of long flows. However, due to the concurrent multiple transfer (CMT) in short flow trans-mission, the congestion window (cwnd) of each MPTCP subflow is too small and it may lead to timeout when a single lost packet cannot be recovered through fast retransmission. As a result, MPTCP has even worse performance for short flows compared to regular TCP. In this paper, we take the first step to analyze the main reason why MPTCP has the diminished performance for short flows, and then we propose MPTCP-SF, which dynamically adjusts the number of subflows for each flow . In particular, MPTCP-SF firstly analyzes the distribution characteristics of the web objects to extract two thresholds to be used for classifying each flow. After eceiving each new ACK, MPTCP-SF periodically counts the data being sent based on per-flow and uses the threshold to classify the we blows. Finally, MPTCP-SF dynamically switches path scheduling model for different classification flows. We conduct extensive experiments in NS3 to evaluate its e fficiency. Our evaluation proves that MPTCP-SF decreases the completion time of short flows by over 42.64% com-pared to MPTCP, and the throughput achieved by MPTCP-SF in transmitting long flows is about 11.11% higher than that of MPTCP in a WLAN/LTE wireless network. The results successfully validate the improved performance of MPTCP-SF.

Network embedding (graph embedding) has become the focus of studying graph structure in recent years. In addition to the research on homogeneous networks and heterogeneous networks, there are also some methods to attempt to solve the problem of dynamic network embedding. However, in dynamic networks, there is no research method specifically for heterogeneous networks. Therefore, this paper proposes a heterogeneous dynamic graph attention network (HDGAN), which attempts to use the attention mechanism to take the heterogeneity and dynamics of the network into account at the same time, so as to better learn network embedding. Our method is based on three levels of attention, namely structural-level attention, semantic-level attention and time-level attention. Structural-level attention pays attention to the network structure itself, and obtains the representation of structural-level nodes by learning the attention coefficients of neighbor nodes. Semantic-level attention integrates semantic information into the representation of nodes by learning the optimal weighted combination of different meta-paths. Time-level attention is based on the time decay effect, and the time feature is introduced into the node representation by neighborhood formation sequence. Through the above three levels of attention mechanism, the final network embedding can be obtained.Through experiments on two real-world heterogeneous dynamic networks, our models have the best results, proving the effectiveness of the HDGAN model.

Today, there is a generalized standard usage of internet for all.The devices via multiple technologies that facilitates to provide few communication methods to scholars to work with. By forming multiple paths in the data center network, latest generation data centers offer maximum bandwidth with robustness. To utilize this bandwidth, it is necessary that different data flows take separate paths. In brief, a single-path transport seems inappropriate for such networks. By using Multipath TCP, we must reconsider data center networks, with a diverse approach as to the association between topology, transport protocols, routing. Multipath TCP allows certain topologies that single path TCP cannot use. In newer generation data centers, Multipath TCP is already deployable using extensively deployed technologies such as Equal-cost multipath routing. But, major benefits will come when data centers are specifically designed for multipath transports. Due to manifold of technologies like Cloud computing, social networking, and information networks there is a need to deploy the number of large data centers. While Transport Control Protocol is the leading Layer-3 transport protocol in data center networks, the operating conditions like high bandwidth, small-buffered switches, and traffic patterns causes poor performance of TCP. Data Center TCP algorithm has newly been anticipated as a TCP option for data centers which address these limitations. It is worth noting that traditional TCP protocol.

The upgrade of network devices to be equipped with multiple network interfaces makes it possible to improve network throughput performance through multipath transmission protocols, especially multipath TCP (MPTCP). However, so far the mostly used MPTCP protocols have a common limitation, namely the rigid and conservative method. They have been designed with little consideration of the fact that real networks are dynamic and the network status changes frequently, thus leading to the poor performance of current MPTCP in many realistic scenarios. In this paper, we propose a lightweight multipath congestion control algorithm based on online learning, named MP-OL. MP-OL models congestion control as a multi-armed bandit problem, and adjusts the sending rate of each subflow flexibly and adaptively through online learning. Therefore, MP-OL possesses the capability of suiting various network scenarios, and can achieve fairness and high performance in dynamic network environment. It can also flexibly switch between online learning and traditional method, which reduces the computational complexity while ensuring the learning efficiency, thus making MP-OL easy to deploy and use. As the experimental results demonstrated, compared with the leading MPTCP variants, MP-OL achieves significant improvements in fairness and link utilization, and shows better resilience to non-congestion loss and better adaptability to unstable network conditions. In real networks, MP-OL also obtains better throughput performance.