Concurrent Multipath Transfer Research Articles

A Review of Multihoming Issues Using the Stream Control Transmission Protocol

Known as multihoming, devices with more than one network interface can enhance their performance capabilities by harnessing unused resources from alternative access networks. Whether it's improved reliability or sheer throughput potential, network devices will benefit from a multihomed framework. Unfortunately, our current means of guaranteeing reliability while maintaining quality control, specifically, the transmission control protocol (TCP), does not support multihoming. Despite the latter, a relatively young transport layer standard called the stream control transmission protocol (SCTP), incorporates multihoming into its design. In this paper, we investigate state-of-the-art multihoming techniques using SCTP. A comprehensive survey of developments has brought forth three main research areas, namely: handover management, concurrent multipath transfer (CMT), and cross-layer activities. While the presented algorithms may offer sufficient results, many open problems still remain.

Multipath state aware concurrent multipath transfer using redundant transmission for multi-homed hosts

Concurrent multipath transport protocols have the potential to improve significantly the throughput performance and resilience of the internet traffic flows. If the data transfer starts to the destined IP, unaware of paths condition, that may result in packet loss and delay in data transfer. This is due to bursty conditions of IP traffic or physical damage. To overcome this, status of the network path is determined before transmission. In our new mechanism multipath state aware concurrent multipath transfer using redundant transfer (MSACMT-RT), status of multipath is determined, initially and periodically before transmission. MSACMT-RT begins immediately after determining the path status, for a particular interval of time and later transfers data with CMT only for predefined period. We demonstrate using simulation under assumption that both the sender/receiver have three paths for CMT. By using MSACMT-RT, it is inferred that our algorithm outperforms better than concurrent multipath transfer potentially failed (CMT-PF). MSACMT-RT mechanism in alternate paths increases the throughput. We present and discuss MSACMT-RT performance in asymmetric paths with the constrained receiver buffer (RBUF) value of 128 KB. We also discuss this scenario with no path failures, frequent and on more frequent path failures with regular and irregular intervals.

Background Traffic-Based Retransmission Algorithm for Multimedia Streaming Transfer over Concurrent Multipaths

The content-rich multimedia streaming will be the most attractive services in the next-generation networks. With function of distribute data across multipath end-to-end paths based on SCTP's multihoming feature, concurrent multipath transfer SCTP (CMT-SCTP) has been regarded as the most promising technology for the efficient multimedia streaming transmission. However, the current researches on CMT-SCTP mainly focus on the algorithms related to the data delivery performance while they seldom consider the background traffic factors. Actually, background traffic of realistic network environments has an important impact on the performance of CMT-SCTP. In this paper, we firstly investigate the effect of background traffic on the performance of CMT-SCTP based on a close realistic simulation topology with reasonable background traffic in NS2, and then based on the localness nature of background flow, a further improved retransmission algorithm, namedRTX_CSI, is proposed to reach more benefits in terms of average throughput and achieve high users' experience of quality for multimedia streaming services.

Performance Metrics of Multipath State Aware Concurrent Multipath Transfer using Redundant Transfer in Stream Control Transmission Protocol Multihoming for Symmetric Paths

Problem statement: In multihomed host, if data transfer starts using CMT, unaware of paths status causes delay in data transfer or packet loss due to path failure. Transmission Path (one or more paths) failures result in out-of-order data delivery causing receiver buffer blocking and preventing sender from transmitting further data. Approach: Multipath State Aware Concurrent Multipath Transfer using Redundant Transfer (MSACMT-RT), status of multipath is determined, initially and periodically before transmission. Data transfer begins immediately after determining the path status, for a particular interval of time and later transfers with CMT only for predefined period. Results: We discuss MSACMT-RT performance in symmetric paths with the constrained receiver buffer (rbuf) value of 128 and 256KB’s. Our simulation result shows Percentage of throughput Increase between 5-15% for transfer of 20 and 40MB file sizes. Conclusion: By using MSACMT-RT we infer that our algorithm outperforms on par or better but never worse than Concurrent Multipath Transfer Potentially Failed (CMT-PF). MSACMT-RT mechanism in alternate paths increases the throughput during aggressive failures and Non-failure scenarios. Larger the file sizes of file transfer, greater the degree of throughput with less transfer time is achieved.

OSIA: Out-of-order Scheduling for In-order Arriving in concurrent multi-path transfer

One major problem of concurrent multi-path transfer (CMT) scheme in multi-homed mobile networks is that the utilization of different paths with diverse delays may cause packet reordering among packets of the same flow. In the case of TCP-like, the reordering exacerbates the problem by bringing more timeouts and unnecessary retransmissions, which eventually degrades the throughput of connections considerably. To address this issue, we first propose an Out-of-order Scheduling for In-order Arriving (OSIA), which exploits the sending time discrepancy to preserve the in-order packet arrival. Then, we formulate the optimal traffic scheduling as a constrained optimization problem and derive its closed-form solution by our proposed progressive water-filling solution. We also present an implementation to enforce the optimal scheduling scheme using cascaded leaky buckets with multiple faucets, which provides simple guidelines on maximizing the utilization of aggregate bandwidth while decreasing the probability of triggering 3 dupACKs. Compared with previous work, the proposed scheme has lower computation complexity and can also provide the possibility for dynamic network adaptability and finer-grain load balancing. Simulation results show that our scheme significantly alleviates reordering and enhances transmission performance.

The unreliable-concurrent multipath transfer (U-CMT) protocol for multihomed networks

Many real-time applications, such as Video on Demand, are sensitive to the transmission delay and allow data loss. Computing devices in multihomed networks are equipped with multiple interfaces such as 3G and Wi-Fi. This work presents an Unreliable Concurrent Multipath Transfer (U-CMT) protocol that satisfies requirements of real-time applications running on multihomed devices. U-CMT is based on Stream Control Transmission Protocol Partial Reliability Extension (PR-SCTP) and the Concurrent Multipath Transfer (CMT) protocol. The novel features of U-CMT are (1) allowance of data loss, (2) sequential data delivery, (3) congestion control, and (4) multipath data transmission. During multipath transfer of unreliable data, congestion control of PR-SCTP may become useless, and receiver buffer blocking occurs. U-CMT uses Path Sequence Number (PSN) to identify data transmission sequence on a per-path basis. The receiver is able to abandon lost data using PSN. As a result, the occurrence of receiver buffer blocking is reduced. Comparing with other protocols, the simulation results show that U-CMT achieves better stable playable frame rate in multihomed networks.

I-SNG: A cost-effective live news broadcasting system over heterogeneous wireless networks

Live satellite news gathering services, featuring real-time streaming of high-quality video, are typically enabled via expensive SNG vehicles and satellite transmissions by TV news companies. With advances in broadband wireless access technologies, delivering live news broadcasting service over broadband wireless networks will become a reality. However, LNB services demand high video fidelity and may consume excessive uplink bandwidth in wireless networks. In addition, the channel condition of terrestrial wireless links between mobile nodes and base stations may vary with time and location, rendering quality of service for LNB services unstable, which is most undesirable to TV news companies. In this article, we share our experience of implementing a novel, cost-effective system called i-SNG for LNB services, under deployment for an M-Taiwan project by a TV company in Taiwan. Specifically, we aggregate bandwidth from locally available heterogeneous wireless networks by employing multilink SCTP, together with Concurrent Multipath Transfer, to cope with limitations in today's network environments. We then perform experiments over a test-bed with different network settings. The experimental results show that, compared with existing solutions, the proposed i-SNG system has superior performance in terms of higher throughput and better perceptual quality, making it an excellent solution for cost-effective LNB services. To the best of our knowledge, this is the first work that uses SCTP-based CMT for bandwidth aggregation in real-time video transmissions.

Performance Evaluation of Multimedia Content Distribution Over Multi-Homed Wireless Networks

The growing availability of IP based heterogeneous wireless access technologies coupled with the increasing capabilities of mobile devices is creating opportunities for multimedia distribution. Through its multi-homing feature, the ability to support multiple network connections in a single end to end association, the transport layer Stream Control Transmission Protocol (SCTP) can enable seamless and transparent communication sessions over multiple heterogeneous networks. This paper analyzes the performance of multimedia distribution when making use of two multi-homing SCTP-based approaches: Single Path Transfer and Concurrent Multi-path Transfer, in which a single or all paths within an association are used simultaneously for data transmission. In this investigation various retransmission policies and different parameter sets are used in turn and recommendations are made for achieving best results during video delivery. In order to perform this study a novel realistic evaluation tool-set was proposed and is described, which can simulate video delivery over SCTP. Our simulation results and analysis show how to optimize the transmission of multimedia content over SCTP associations in both single and multipath scenarios.

Fast Retransmission for Concurrent Multipath Transfer (CMT) over Vehicular Networks

In vehicular networks, a vehicle can connect to a nearby Rode Side Unit (RSU) covered by a relay gateway using IEEE 802.11p. When a vehicle communicates with a server, the link between the vehicle and RSU is a wireless link, while the link between the gateway and the server is a wired link. In most cases, packets are lost in the wireless link, not in the wired link. In this paper, we propose fast retransmission made by the Relay Gateway for Concurrent Multipath Transfer (RG-CMT) in vehicular networks. When packets are lost due to error loss or handoff loss in the wireless link, RG-CMT is able to fast retransmit lost packets from the relay gateway to the vehicle. Comparing to fast retransmission made by the server, retransmission made by the relay gateway saves transmission time and bandwidth. The simulation results show that RG-CMT can recover from handoff faster than CMT, and improve the throughput of CMT by 41% when the packet loss rate over the IEEE 802.11p link is 10%.

Multimedia streaming using partially reliable concurrent multipath transfer for multihomed networks

The authors propose a partially reliable-concurrent multipath transfer (PR-CMT) protocol for multimedia streaming. The novelty of PR-CMT is to combine techniques of CMT's concurrent multipath transfer, PR-SCTP's partially reliable transmission and prioritised stream transmission. Moving picture experts group (MPEG) frames are with varying priorities and lifetime. PR-CMT can transmit important frames before other frames but does not transmit lifetime expired frames. The combination of the aforementioned techniques, however, causes imprecise congestion window and receiver buffer blocking problems without suitable control. Consequently, the throughput and video quality degrade. PR-CMT adopts the concept of delay abandoning data to resolve the imprecise cwnd and the receiver buffer blocking problems. The simulation results show that PR-CMT can precisely infer cwnd. Most importantly, PR-CMT can prevent large gaps between two playable frames to have good video quality.

Introducing multipath selection for concurrent multipath transfer in the future internet

It is essential for the Future Internet to fully support multihoming and select most appropriate paths for Concurrent Multipath Transfer (CMT). In real complex networks, different paths are likely to overlap each other and even share bottlenecks which can weaken the path diversity gained through CMT. Spurred by this observation, it is necessary to select multiple independent paths insofar as possible. However, the path correlation lurks behind the IP/network layer topology, so we have to fall back to end-to-end probes to estimate this correlation by analyzing path delay characteristics. In this paper, we present the first step towards a new topic of correlation-aware multipath selection, with formal and systematic problem definition, modeling and solution. Based on a well-designed delay probing, a Grouping-based Multipath Selection (GMS) mechanism is developed to avoid underlying shared bottlenecks between topologically joint paths. In addition, we further propose a practical functionality framework and define a novel multihoming sublayer for the exchange of the multipath capabilities. Extensive simulations demonstrate that the GMS under different network conditions performs much better than other selection schemes, even with burst background traffic.

SCTP-based concurrent multipath transfer in wireless network

With the increasing diversity in network access technology and the lower cost of access device, more and more mobile terminals have multi-homing property. But current TCP /IP protocol stack can only use single interface for transmission, and it cannot make full advantage of multi-homing. On the basis of Stream Control Transmission Protocol ( SCTP) , this paper designed path selection module and fast path handover module and implemented a solution for wireless Concurrent Multipath Transfer ( CMT) , which made using multiple interfaces to transmit at the same time available. The effects of bandwidth aggregation and fast path handover of Wireless CMT were tested in a real wireless network environment. The test results reveal that the Wireless CMT obviously improves the efficiency and reliability of wireless transmission.

Distributed rate allocation for elastic flows in concurrent multipath transfer

Distributed rate allocation for elastic flows in concurrent multipath transfer

A simulation-based study of FAST TCP compared to SCTP: Towards multihoming implementation using FAST TCP

The current multihome-aware protocols (like stream control transmission protocol (SCTP) or parallel TCP for concurrent multipath data transfer (CMT) are not designed for high-capacity and large-latency networks; they often have performance problems transferring large data files over shared long-distance wide area networks. It has been shown that SCTP-CMT is more sensitive to receive buffer (rbuf) constraints, and this rbuf-blocking problem causes considerable throughput loss when multiple paths are used simultaneously. In this research paper, we demonstrate the weakness of SCTP-CMT rbuf constraints, and we then identify that rbuf-blocking problem in SCTP multihoming is mostly due to its loss-based nature for detecting network congestion. We present a simulation-based performance comparison of FAST TCP versus SCTP in high-speed networks for solving a number of throughput issues. This work proposes an end-to-end transport layer protocol (i.e., FAST TCP multihoming as a reliable, delay-based, multihome-aware, and selective ACK-based transport protocol), which can transfer data between a multihomed source and destination hosts through multiple paths simultaneously. Through extensive ns-2 simulations, we show that FAST TCP multihoming achieves the desired goals under a variety of network conditions. The experimental results and survey presented in this research also provide an insight on design decisions for the future high-speed multihomed transport layer protocols.

Concurrent multipath transfer protocol used in ad hoc networks

This study studies the received buffer blocking problem caused by traditional concurrent multipath transfer protocol. The authors propose a new transport protocol, named wireless concurrent multipath transfer stream control transport protocol (WCMT-SCTP), to solve the received buffer blocking problem. It can bind certain data streams to certain paths and use multiple active paths to transfer data simultaneously. The authors evaluate the performance of WCMT-SCTP through theoretical analysis and extensive simulation. Both simulation and analysis results show WCMT-SCTP can improve the system throughput obviously and keep the independence of data streams.

Employing transport layer multi-railing in cluster networks

Building clusters from commodity off-the-shelf parts is a well-established technique for building inexpensive medium- to large-size computing clusters. Many commodity mid-range motherboards come with multiple Gigabit Ethernet interfaces, and the low cost per port for Gigabit Ethernet makes switches inexpensive as well. Our objective in this work is to take advantage of multiple inexpensive Gigabit network cards and Ethernet switches to enhance the communication and reliability performance of a cluster. Unlike previous approaches that take advantage of multiple network connections for multi-railing, we consider CMT (Concurrent Multipath Transfer) that extends SCTP (Stream Control Transmission Protocol), a transport protocol developed by the IETF, to make use of the multiple paths that exist between two hosts. In this work, we explore the applicability of CMT in the transport layer of the network stack to high-performance computing environments. We develop SCTP-based MPI (Message Passing Interface) middleware for MPICH2 and Open MPI, and evaluate the reliability and communication performance of the system. Using Open MPI with support for message striping over multiple paths at the middleware level, we compare the differences in supporting multi-railing in the middleware versus at the transport layer.

The Design of Mobile Concurrent Multipath Transfer in Multihomed Wireless Mobile Networks

As more and more devices are equipped with multiple network interfaces, the multihomed technology is becoming an important technology that can provide more reliable connection against the network failure and higher data transmission rate. Concurrent Multipath Transfer (CMT), which is based on SCTP, is devised for multihomed networks. CMT can transmit data over all paths to maximize the data transmission speed. One of the main concerns of CMT is the receiver buffer blocking issue, especially in multihomed wireless mobile networks. Receiver buffer blocking is mainly caused by lost data. In this paper, we propose mobile CMT (mCMT) over wireless networks to deal with the receiver buffer blocking caused by error loss and handoff loss. mCMT has the features of (i) path-oriented multistreaming, (ii) MIH-assisted handoff mechanism, in which MIH denotes Media Independent Handover and (iii) association resume. Path-oriented multistreaming can reduce the receiver buffer blocking caused by error loss. MIH-assisted a handoff can reduce the amount of packet loss during a handoff, which may lead to receiver buffer blocking. Moreover, mCMT introduces the concept of association resume to recover the disconnected association. Simulation results show that mCMT can reduce the effect of the receiver buffer blocking effectively for devices that have smaller buffer size.

Concurrent Multipath Transfer during path failure

We investigate how path failure influences Concurrent Multipath Transfer (CMT) using SCTP multihoming. We show that CMT suffers from significant “receive buffer blocking” which degrades performance during both permanent and short-term failure. To improve performance, we introduce a new “Potentially-Failed” (PF) destination state, and revise CMT’s failure detection and (re)transmission policies to include the PF state. Using simulation, we demonstrate that the modification called CMT-PF outperforms CMT during failure – even with aggressive failure detection thresholds and varying receive buffer constraints. In non-failure scenarios, CMT-PF performs on par or better but never worse than CMT. Finally, we confirm these simulation results using FreeBSD implementations of CMT and CMT-PF. Based on our findings, we recommend CMT-PF be used in existing and future CMT implementations and RFCs.

A multi-path mechanism for reliable VoIP transmission over wireless networks

With the advances in audio encoding standards and wireless access networks, voice over IP (VoIP) is becoming quite popular. However, real-time voice data over lossy networks (such as WLAN and UMTS), still posses several challenging problems because of the adverse effects caused by complex network dynamics. One approach to provide QoS for VoIP applications over the wireless networks is to use multiple paths to deliver VoIP data destined for a particular receiver. This paper introduced cmpSCTP, a transport layer solution for concurrent multi-path transfer that modifies the standard stream control transmission protocol (SCTP). The cmpSCTP aims at exploiting SCTP's multi-homing capability by selecting several best paths among multiple available network interfaces to improve data transfer rate to the same multi-homed device. Through the use of path monitoring and packet allotment techniques, cmpSCTP tries to transmit an amount of packets corresponding to the path's ability. At the same time, cmpSCTP updates the transmission strategy based on the real-time information of all of paths. Using cmpSCTP's flexible path management capability, we may switch the flow between multiple paths automatically to realize seamless path handover. The theoretical analysis evaluated the model of cmpSCTP and formulated optimal traffic fragmentation of VoIP data. Extensive simulations under different scenarios using OPNET verified that cmpSCTP can effectively enhance VoIP transmission efficiency and highlighted the superiority of cmpSCTP against the other SCTP's extension implementations under performance indexes such as throughput, handover latency, packet delay, and packet loss.

Latent Handover: A flow-oriented progressive handover mechanism

The next generation network may be regarded as an IP (Internet Protocol) converged network, combining various access technologies. In this environment, ubiquitous computing and seamless networking are required for the mobile host. The growing availability of multiple network interfaces on mobile devices makes Concurrent Multi-path Transfer (CMT) an appealing candidate to realize the seamless handover. In this paper, we proposed a novel Latent Handover mechanism, which is flow-oriented and switches the traffic to the new path progressively to make the handover process unconscious to users or upper layer applications, especially real-time services. In addition, to support the proposed Latent Handover, the transport layer introduces our proposed cmpSCTP (concurrent multi-path Stream Control Transmission Protocol), which adds concurrent multi-path transfer and dynamic Multi-Path Management support to the standard SCTP for realizing seamless handover. The theoretical analysis verified that the proposed Latent Handover can efficiently optimize the handover process and enhance transmission efficiency during handover. Extensive simulations under different scenarios using OPNET highlighted the superiority of the proposed Latent Handover solution against other existing handover schemes under performance indexes such as throughput, handover latency, packet delay, and packet loss.