Conference Paper

The Performance Impact of Buffer Sizes for Multi-Path TCP in Internet Setups

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Abstract

The Multi-Path Transmission Control Protocol (MPTCP) is the new concurrent multi-path transfer extension for the widely-deployed Transmission Control Protocol (TCP). Of course, having multiple and possibly highly dissimilar paths for transmission is a challenge for the management of the send and receive buffers, since optimal throughput is desired with a reasonable allocation of the limited memory resources in MPTCP endpoints. This is particularly important when many MPTCP connections have to be handled simultaneously. This paper measures out the required MPTCP buffer size in the real-world Internet testbed NorNet, comparing theoretical size and real size to analyse MPTCP performance. The experiment shows that multi-path transmission can effectively increase the application payload throughput, and greatly improve the robustness of the data transmission. As an important point of this paper, we can show that appropriate buffer size settings can increase the payload throughput, while not wasting resources. This paper has certain significance for further accurately determining the optimal buffer size settings for multi-path transmission in large-scale Internet setups.

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... Effectively utilizing the redundant network resources and improving the network performance -despite the very dissimilar characteristics of the underlying networks -have become a hot issue in recent years. Therefore, the Internet Engineering Task Force (IETF) puts forward the Multi-Path Transmission Control Protocol (MPTCP) [1]- [4], which can aggregate the bandwidths, improve the throughput, as well as enhance the robustness and fast recovery by using the existing network infrastructure in the way of software. ...
... While TCP only establishes a single-path connection for the communication between two hosts, MPTCP can dynamically conduct a multi-path connection consisting of multiple subflows. Subfigure 1(a) illustrates the MPTCP protocol stack [4]. It can be seen that MPTCP provides transparent end-to-end concurrent data transmission services to achieve the purpose of aggregating bandwidth and improving transport performance. ...
... • Ubuntu Linux 16.04 "Xenial Xerus" LTS with Linux kernel version 4.19.128, • Linux MPTCP version 0.95, • Buffer size limit set to 16 MiB, to prevent throughput limitations by lack of buffer space [4]. ...
... MPTCP needs to mainly carry out two tasks [11], [12], as depicted in Figure II-A: one is Packet Scheduling (PS), which is linked with data scheduling, interfacing with the subflows, and congestion control. Another is Path Management (PM) [13], which manages the communication paths, i.e. subflows between source/destination IP address pairs. ...
... leaving the receive buffer). [11] explains that, in order to cover the worst-case retransmission situation, a buffer size B is needed: ...
... For all measurements, we used the following configuration: (a) Linux kernel version 4.4.84, (b) Linux MPTCP [35] version 0.92.1 6 using the "fullmesh" path manager (to use all possible paths [13], [36] Table I THE NORNET CORE TESTBED SITES USED FOR THE MEASUREMENTS • Initial path selection [13], and • Buffer size settings [11]. We designed a Python script that generates data for statistical analysis by measuring throughput at various values of network parameters listed above. ...
... There are several studies on the performance evaluation of MPTCP through heterogeneous paths [5][6][7][8][9][10][11]. Although they give new findings and proposals, they have some problems. ...
... There are some recent studies on MPTCP performance [10,11]. J. Kim et al. [10] proposes a scheduler using the buffer blocking prediction based on receive buffer size and RTT, but they do not care about the send socket buffer size. ...
... J. Kim et al. [10] proposes a scheduler using the buffer blocking prediction based on receive buffer size and RTT, but they do not care about the send socket buffer size. F. Zhou et al. [11] shows the MPTCP performance evaluation over the real Internet by changing socket buffer size, but they assume that the sizes of send and receive socket buffers are the same. ...
Chapter
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Recently, the multipath transport protocol such as Multipath TCP becomes increasingly important. It allows more than one TCP connections via different paths to compose one Multipath TCP communication. However, it has some problems when those paths have different delay. Especially, the limited buffer space at either sender or receiver may degrade the throughput due to head-of-line blocking. Our previous paper pointed out that insufficient send socket buffer and receive socket buffer provide different situations of performance degradation, and that insufficient send socket buffer gives poorer throughput. This paper extends the performance analysis of our previous paper in the conditions with various combinations of send socket buffer size and transmission delay. It gives more detailed analysis using Multipath TCP level sequence number and congestion window size, and suggests the reasons for performance degradation.
... MPTCP [1,2] is an extension of the well-known Transmission Control Protocol (TCP) [3]. It realizes multi-path transmission on the transport layer. ...
... However, MPTCP can dynamically conduct a multi-path connection consisting of multiple flows. Figure 1a illustrates the MPTCP protocol stack [2,4]. MPTCP transfers data simultaneously over different subflows, as depicted in Figure 1a. ...
Article
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The transmission performance of a multi-path transmission control protocol (MPTCP) is affected by many parameters, such as path management, congestion control, buffer size, and subflow bandwidth. Most of the previous studies have focused almost exclusively on the improvement of a single parameter, without a holistic view. In this paper, a multi-parameter comprehensive optimized algorithm (MPCOA) is proposed to comprehensively optimize the above parameters. The MPCOA algorithm can find a smaller buffer size and select an appropriate congestion control and path management algorithm on the premise of ensuring better throughput. Experiments in three scenarios show that MPCOA can save buffer space and subflow resources, and achieve a high throughput. Meanwhile, a set of quantitative improvement results given by MPCOA is convenient for us to evaluate the quality of the MPTCP network and provide reference for our ongoing future work.
... MPTCP uses multiple subflows to implement concurrent multipath transport [42]. Each subflow is defined by a source/destination IP address pair and appears as a regular TCP connection. ...
... In the traditional Internet, timer-based retransmissions should be rare; however, they must be considered due to the characteristics of MANETs. Hence, to utilize a network path and cover fast retransmission and timer-based retransmission, the send/receive buffer size constraint B is shown in the following formula [42]. In the worst case, it takes three times the highest subflow RTT (first transmission, fast retransmission, timer-based retransmission) plus the highest subflow RTO (retransmission timeout). ...
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... Furthermore, whenever bottleneck buffer is not properly adjusted, we can encounter the effect of "bufferbloat". Although it is an inter-related issue with regard to the receiver buffer as already addressed in [12], it was extensively analysed in [13] for wireless, and in [14] for terrestrial networks, where the traffic on links with high propagation delay experienced an RTT exceeding 7 s. In presence of such a large amount of packets in flight, there is a MP-TCP layer performance reduction in terms of aggregated throughput. ...
... In fact assuming a strict configuration may reduce the flexibility and the feasibility of the network configuration, and it is not suitable when the link characteristic changes. Such limit is set using Eq. 2, inferred from [14], where that value was proposed as size for the receiver buffer. ...
... While there are various articles on all aspects of the multipath transport protocols, e.g. congestion control [8]- [10], path management [11], buffer management [12], [13], shared bottleneck detection [14], handling of latency-sensitive traffic [15] and media streaming [16], [17], little work has been done to examine the properties of the underlying networks. In many cases, our Open Source tool NETPERFMETER 2 [18], [19] [1, Section 6.3] has been used to conduct Transport Layer performance measurements. ...
... Moreover, both TCP and MPTCP have more stable throughput performance when there is enough cache space. The buffer required to achieve stable maximum network throughput in MPTCP is close to 3 times that of TCP cache [9], which consumes a lot of cache space. Actually the buffer pool of the commercial Ethernet switch is usually small. ...
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... The severer the network load dynamism is, the larger it should be. The work in [43] adopts 3 in the Internet context. The performance of such a solution will be evaluated later in Section V-D2. ...
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Bandwidth guarantee is a critical feature to enable performance predictability in cloud datacenters. This process is expected to achieve three requirements: work conservation, fairness, and simplicity. However, the distributed nature of datacenters raises significant challenges to attaining those requirements at the same time. In this paper, we propose an efficient approach that can satisfy the three requirements simultaneously. Our scheme takes advantage of multipath TCP (MPTCP) to generate explicit bandwidth guarantee (BG) traffic and work conservation (WC) traffic. We further prioritize the BG traffic over the WC traffic in the network fabric. Due to the priority setting, work conservation cannot harm bandwidth guarantees and thus is effectively supported. We show that MPTCP fits this direction well but presents some new issues when the WC subflows own a low priority. We thus adapt MPTCP to handle these issues through a customized scheduler (which strictly prioritizes BG subflow during packet scheduling) and adopting a large receive buffer. In addition, we enable tenants to share unused bandwidth fairly by managing the overall aggressiveness ofWCtraffic. The proposed system can be easily implemented with commercial off-the-shelf servers and switches. We have implemented with Linux kernel MPTCP for experiments. Extensive experiments in a small cluster (including one MapReduce experiment) and tracedriven simulations show that our scheme achieves the design goals effectively.
... Therefore, another milestone is Multi-Path TCP (MPTCP) [16,24], providing transport redundancy by multi-homing without changing the existing network infrastructure. It also supports load balancing over heterogeneous networks connections [15,17,27,30]. But MPTCP is not only useful when an endpoint is connected to multiple Internet connections. ...
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Today, a steadily increasing number of users are not just passively consuming Internet content, but also share and publish content. Users publish text, photos and videos. With the availability of 5G high-speed, low-latency mobile broadband networks, real-time video streaming will also be possible. We believe this will become a very popular application in the coming years. But the more popular a service is, the higher the need for resilience. In this paper, we introduce our work-in-progress live video streaming platform for future mobile edge computing scenarios, which makes use of MPTCP+IPv6 to support multi-homing for resilience and multi-path transport for load balancing. As a proof of concept, we will show that the platform is (1) compatible with IPv6, (2) utilizes load balancing when possible and (3) provides robustness by network redundancy.
... (a) Linux kernel version 4.1.27, (b) Linux MPTCP [15] version 0.91 2 , (c) ndiffports=2 (only relevant for "ndiffports" path manager), (d) Explicit Congestion Notification (ECN) support [40], [41] enabled, and (e) TCP (and MPTCP) buffer size limit [42] set to 16 MiB 3 (in order to avoid effects caused by buffer space scarcity). ...
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Multi-homed Internet sites become more and more widespread, due to the rising dispersal of inexpensive Internet access technologies combined with the growing deployment of resilience-critical applications. Concurrent Multipath Transfer (CMT) denotes the Transport Layer approach to utilise multiple network paths simultaneously, in order to improve application payload throughput. Currently, CMT is a quite hot topic in the IETF - in form of the Multipath TCP (MPTCP) and CMT-SCTP protocol extensions for TCP and SCTP. However, an important issue is still not fully solved: multipath congestion control. In order to support the IETF activities, we have set up a distributed Internet testbed for CMT evaluation. An important tool - which we have developed for multiprotocol Transport Layer performance analysis - is the Open Source NetPerfMeter tool-chain. It supports the parametrisation and processing of measurement runs as well as results collection, post-processing and plotting. However, its key feature is to support multiple Transport Layer protocols, which makes a quantitative comparison of different protocols - including state-of-the-art features like CMT - possible. In this paper, we first introduce NetPerfMeter and then show a proof-of-concept performance evaluation of CMT congestion controls which are currently discussed in the IETF standardisation process of CMT-SCTP.
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The Stream Control Transmission Protocol (SCTP) is a general-purpose transport layer protocol providing a service similar to TCP - plus a set of advanced features to utilize the enhanced capabilities of modern IP networks and to support increased application requirements. Nowadays, there are SCTP implementations for all major operating systems. While SCTP was standardized as an RFC several years ago, there is still significant ongoing work within the IETF to discuss and standardize further features in the form of protocol extensions. In this article, we first introduce the SCTP base protocol and already standardized extensions. After that, we focus on the ongoing SCTP standardization progress in the IETF and give an overview of activities and challenges in the areas of security and concurrent multipath transport.
Conference Paper
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With the deployment of more and more resilience-critical Internet applications, there is a rising demand for multi-homed network sites. This leads to the desire for simultaneously utilising all available access paths to improve application data throughput. This is commonly known as Concurrent Multipath Transfer (CMT); approaches for several Transport Layer protocols have been proposed. Combined with Resource Pooling (RP), CMT can also fairly coexist with concurrent non-CMT flows. Current approaches focus on symmetric paths (i.e. similar bandwidth, delay and error rate). However, asymmetric paths are much more likely - particularly for realistic Internet setups - and efficient CMT usage on such paths is therefore crucial. In this paper, we first show the challenges of plain as well as RP-aware CMT data transport over asymmetric paths. After that, we introduce mechanisms for efficient transport over such paths. Finally, we analyse the performance of our approaches by using simulations.
Conference Paper
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The steadily growing deployment of resilience- critical Internet services is leading to an increasing number of Multi-Homed network sites. Asymmetric Digital Subscriber Lines (ADSL) are an inexpensive way to add a secondary Internet access connection. With the development of Multi-Path Transport Layer protocols - like Multipath TCP (MPTCP) and the Stream Control Transmission Protocol (SCTP) furnished by a Concur- rent Multipath Transfer (CMT-SCTP) extension - there is also a strong interest in utilising all access connections simultaneously to improve the data throughput of the applications. However, combining network paths over ADSL with paths over other access technologies like fibre optic links implies highly dissimilar paths with significantly different bandwidths, delays and queuing behaviours. Efficient Multi-Path transport over such dissimilar paths is a challenging task for the new Transport Layer protocols under development. In this paper, we show the difficulties of Multi-Path transport in a real-world dissimilar path setup which consists of a high- speed fibre optic link and an ADSL connection. After that, we present an optimised buffer handling technique which solves the transport efficiency issues in this setup. Our optimisation is first analysed by simulations. Finally, we also show the usefulness of our approach by experimental evaluation in a real Multi-Homed Internet setup. 1234
Conference Paper
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Recently new data center topologies have been proposed that offer higher aggregate bandwidth and location independence by creating multiple paths in the core of the network. To effectively use this bandwidth requires ensuring different flows take different paths, which poses a challenge. Plainly put, there is a mismatch between single-path transport and the multitude of available network paths. We propose a natural evolution of data center transport from TCP to multipath TCP. We show that multipath TCP can effectively and seamlessly use available bandwidth, providing improved throughput and better fairness in these new topologies when compared to single path TCP and randomized flow-level load balancing. We also show that multipath TCP outperforms laggy centralized flow scheduling without needing centralized control or additional infrastructure.
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This paper presents a new TCP variant, called CUBIC, for high-speed network environments. CUBIC is an enhanced version of BIC: it simplifies the BIC window control and improves its TCP-friendliness and RTT-fairness. The window growth function of CUBIC is governed by a cubic function in terms of the elapsed time since the last loss event. Our experience indicates that the cubic function provides a good stability and scalability. Furthermore, the real-time nature of the protocol keeps the window growth rate independent of RTT, which keeps the protocol TCP friendly under both short and long RTT paths. Index Terms—Congestion Control, High-Speed TCP, TCP Friendliness
Conference Paper
With the rapid development of Internet communications, there is a growing demand to support devices being connected to multiple Internet service providers simultaneously. For example, every modern smartphone already provides at least mobile broadband (UMTS, LTE) as well as Wi-Fi interfaces. This multi-homing property can be used for resilience, but there is also an increasing interest in making use of concurrent multi-path transport. That is, multiple network paths can be utilised simultaneously, in order to improve the payload throughput for applications like big data or cloud computing. In this paper, we examine the performance of multi-path transport in real-world Internet setups, based on Multi-Path TCP (MPTCP) in the NorNet testbed for multi-homed systems. However, systems in such challenging setups need proper configuration. Therefore, we particularly would like to highlight the performance impact of different path management and congestion control settings in such realistic scenarios.
NetPerfMeter: A Network Performance Metering Tool
  • T Dreibholz
T. Dreibholz, "NetPerfMeter: A Network Performance Metering Tool," Multipath TCP Blog, Sep. 2015.
Dynamic Reservation Data Scheduling Mechanism for MPTCP
  • Qing Hu
  • Zou Ran
  • Liu Peng
Qing Hu and Zou Ran and Liu Peng, "Dynamic Reservation Data Scheduling Mechanism for MPTCP," Journal of Chongqing University of Posts and Telecommunications, vol. 25, no. 6, 2013.
The Benefits of using Explicit Congestion Notification (ECN), " IETF, Internet Draft draft-ietf-aqm-ecn-benefits-08
  • G Fairhurst
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G. Fairhurst and M. Welzl, " The Benefits of using Explicit Congestion Notification (ECN), " IETF, Internet Draft draft-ietf-aqm-ecn-benefits-08, Nov. 2015.
Forward Prediction Data Scheduling Mechanism for MPTCP
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Q. Hu, R. Zhou, and L. Zhou, "Forward Prediction Data Scheduling Mechanism for MPTCP," Application Research of Computers, vol. 30, no. 2, pp. 560-561, Feb. 2013, ISSN 1001-3695.
Load Sharing for the Stream Control Transmission Protocol (SCTP), " IETF, Individual Submission, Internet Draft draft-tuexen-tsvwg-sctp-multipath-13
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  • N Ekiz
  • J R Iyengar
  • P Natarajan
  • R R Stewart
  • M Tüxen
P. D. Amer, M. Becke, T. Dreibholz, N. Ekiz, J. R. Iyengar, P. Natarajan, R. R. Stewart, and M. Tüxen, " Load Sharing for the Stream Control Transmission Protocol (SCTP), " IETF, Individual Submission, Internet Draft draft-tuexen-tsvwg-sctp-multipath-13, Dec. 2016.
TCP Extensions for Multipath Operation with Multiple Addresses
  • A Ford
  • C Raiciu
  • M Handley
  • O Bonaventure
A. Ford, C. Raiciu, M. Handley, and O. Bonaventure, "TCP Extensions for Multipath Operation with Multiple Addresses," IETF, RFC 6824, Jan. 2013, ISSN 2070-1721.
Architectural Guidelines for Multipath TCP Development
  • A Ford
  • C Raiciu
  • M Handley
  • S Barré
  • J R Iyengar
A. Ford, C. Raiciu, M. Handley, S. Barré, and J. R. Iyengar, "Architectural Guidelines for Multipath TCP Development," IETF, Informational RFC 6182, Mar. 2011, ISSN 2070-1721.
Non-Renegable Selective Acknowledgements (NR-SACKs) for MPTCP IETF, Individual Submission, Internet Draft draft-deng- mptcp-nrsack-00
  • Z Deng
Z. Deng, " Non-Renegable Selective Acknowledgements (NR-SACKs) for MPTCP, " IETF, Individual Submission, Internet Draft draft-deng- mptcp-nrsack-00, Dec. 2013.
Performance Analysis of MPTCP and CMT-SCTP Multi-Path Transport Protocols
  • F Fu
  • Z Xing
  • Y Xiong
  • H Adhari
  • E P Rathgeb
F. Fu, Z. Xing, Y. Xiong, H. Adhari, and E. P. Rathgeb, "Performance Analysis of MPTCP and CMT-SCTP Multi-Path Transport Protocols," Computer Engineering and Applications, vol. 49, no. 21, pp. 79-82, Oct. 2013.
  • M Allman
  • V Paxson
  • E Blanton
M. Allman, V. Paxson, and E. Blanton, " TCP Congestion Control, " IETF, Standards Track RFC 5681, Sep. 2009, ISSN 2070-1721.
Multipath TCP Middlebox Behavior IETF, Individual Submission, Internet Draft draft-lopez-mptcp-middlebox-00
  • E Lopez
E. Lopez, " Multipath TCP Middlebox Behavior, " IETF, Individual Submission, Internet Draft draft-lopez-mptcp-middlebox-00, Nov. 2014.
  • C Raiciu
  • C Pluntke
  • S Barré
  • A Greenhalgh
  • D Wischik
  • M Handley
C. Raiciu, C. Pluntke, S. Barré, A. Greenhalgh, D. Wischik, and M. Handley, "Data Center Networking with Multipath TCP," in Proceedings of the 9th ACM SIGCOMM Workshop on Hot Topics in Networks, Monterey, California/U.S.A., Oct. 2010, pp. 1-6, ISBN 978-1-4503-0409-2.
IETF, Individual Submission, Internet Draft draft-lopez-mptcp-middlebox-00
  • E Lopez
E. Lopez, "Multipath TCP Middlebox Behavior," IETF, Individual Submission, Internet Draft draft-lopez-mptcp-middlebox-00, Nov. 2014.
TCP Congestion Control
  • M Allman
  • V Paxson
  • E Blanton
M. Allman, V. Paxson, and E. Blanton, "TCP Congestion Control," IETF, Standards Track RFC 5681, Sep. 2009, ISSN 2070-1721.
Load Sharing for the Stream Control Transmission Protocol (SCTP)
  • P D Amer
  • M Becke
  • T Dreibholz
  • N Ekiz
  • J R Iyengar
  • P Natarajan
  • R R Stewart
  • M Tüxen
P. D. Amer, M. Becke, T. Dreibholz, N. Ekiz, J. R. Iyengar, P. Natarajan, R. R. Stewart, and M. Tüxen, "Load Sharing for the Stream Control Transmission Protocol (SCTP)," IETF, Individual Submission, Internet Draft draft-tuexen-tsvwg-sctp-multipath-13, Dec. 2016.
Non-Renegable Selective Acknowledgements (NR-SACKs) for MPTCP
  • Z Deng
Z. Deng, "Non-Renegable Selective Acknowledgements (NR-SACKs) for MPTCP," IETF, Individual Submission, Internet Draft draft-dengmptcp-nrsack-00, Dec. 2013.
The Benefits of using Explicit Congestion Notification (ECN)
  • G Fairhurst
  • M Welzl
G. Fairhurst and M. Welzl, "The Benefits of using Explicit Congestion Notification (ECN)," IETF, Internet Draft draft-ietf-aqm-ecn-benefits-08, Nov. 2015.