SDN based testbeds for evaluating and promoting multipath TCP

Lecture Notes in Computer Science, 2011

The IETF is developing a new transport layer solution, Mul-tiPath TCP (MPTCP), which allows to efficiently exploit several Internet paths between a pair of hosts, while presenting a single TCP connection to the application layer. From an implementation viewpoint, multiplexing flows at the transport layer raises several challenges. We first explain how this major TCP extension affects the Linux TCP/IP stack when considering the establishment of TCP connections and the transmission and reception of data over multiple paths. Then, based on our implementation of MultiPath TCP in the Linux kernel, we explain how such an implementation can be optimized to achieve high performance and report measurements showing the performance of receive buffer tuning and coupled congestion control.

ACM SIGCOMM Computer Communication Review, 2011

The latest large-scale data centers offer higher aggregate bandwidth and robustness by creating multiple paths in the core of the network. To utilize this bandwidth requires different flows take different paths, which poses a challenge. In short, a single-path transport seems ill-suited to such networks.

2021 IFIP Networking Conference (IFIP Networking), 2021

Multipath TCP (MPTCP) extends traditional TCP to enable simultaneous use of multiple connection endpoints at the source and destination. MPTCP has been under active development since its standardization in 2013, and more recently in February 2020, MPTCP was upstreamed to the Linux kernel. In this paper, we provide the first broad analysis of MPTCPv0 in the Internet. We probe the entire IPv4 address space and an IPv6 hitlist to detect MPTCP-enabled systems operational on port 80 and 443. Our scans reveal a steady increase in MPTCPcapable IPs, reaching 9k+ on IPv4 and a few dozen on IPv6. We also discover a significant share of seemingly MPTCP-capable hosts, an artifact of middleboxes mirroring TCP options. We conduct targeted HTTP(S) measurements towards select hosts and find that middleboxes can aggressively impact the perceived quality of applications utilizing MPTCP. Finally, we analyze two complementary traffic traces from CAIDA and MAWI to shed light on the real-world usage of MPTCP. We find that while MPTCP usage has increased by a factor of 20 over the past few years, its traffic share is still quite low.

This paper focuses on evaluating the use of MPTCP to forward subflows in OpenFlow networks. MPTCP is a network protocol designed to forward subflows through disjointed paths. Modern networks commonly use Equal-Cost Multipath Protocol (ECMP) to split flows through distinct paths. However, even with ECMP enabled, subflows may be forwarded through the same path. MPTCP improves the multipath routing by setting subflows to be forwarded through distinct paths. As a consequence, the amount of subflows must be considered to evaluate the network throughput. In this paper, we design Multiflow to use MPTCP in OpenFlow networks. Our proposal is to improve the throughput in shared bottlenecks by forwarding subflows from a same MPTCP connection through multiple paths. We validate our approach in a testbed where shared bottlenecks occur in the link at the endpoints. The Multiflow improvement of the network performance is evaluated in experiments about resilience and end-to-end throughput. - The 29th IEEE International Conference on Advanced Information Networking and Applications (AINA-2015) Gwangju, Korea, March 25-27, 2015

Proceedings of the 2018 ACM SIGSIM Conference on Principles of Advanced Discrete Simulation

Assessing the impact of changes in a production network (e.g., new routing protocols or topologies) requires simulation or emulation tools capable of providing results as close as possible to those from a real-world experiment. Large traffic loads and complex controldata plane interactions constitute significant challenges to these tools. To meet these challenges we propose a model for the fast and convenient evaluation of SDN as well as legacy networks. Our approach emulates the network's control plane and simulates the data plane, to achieve high fidelity necessary for control plane behavior, while being capable of handling large traffic loads. We design and implement a proof of concept from the proposed model. The initial results of the prototype, compared to a state-of-the-art solution, shows it can increase the speed of network experiments by nearly 95% in the largest tested network scenario.

2017 13th International Conference on Network and Service Management (CNSM), 2017

Traffic engineering technologies such as MPLS have been proposed to adjust the paths of data flows according to network availability. Although the time interval between traffic optimisations is often on the scale of hours or minutes, modern SDN techniques enable reconfiguring the network more frequently. It is argued, however, that changing the paths of TCP flows too often could severely impact their performance by incurring packet loss and reordering. This work analyses and evaluates the impact of frequent route changes on the performance of TCP flows. Experiments carried out on a network testbed show that rerouting a flow can affect its throughput when reassigning it a path either longer or shorter than the original path. Packet reordering has a negligible impact when compared to the increase of RTT. Moreover, constant rerouting influences the performance of the congestion control algorithm. Designed to assess the limits on SDN-induced reconfiguration, a scenario where the traffic is rerouted every 0.1s demonstrates that the throughput can be as low as 35% of that achieved without rerouting.

2011

We present a survey on multipath transport protocols. These protocols are aiming to provide a way for the use of simultaneous paths at the transport layer and load balancing traffic on these paths. We describe some of the main proposal and then we focus on MPTCP (Multipath TCP) which is a promising extension of TCP currently considered by the recent eponymous IETF working group.

2021

The software-defined networking (SDN) paradigm has gained widespread popularity due to its ability to ease network management. However, the traditionally used centralized SDN architectures are restricted by scalability issues. To cope with these, several distributed alternatives have been proposed. The performance evaluation of such distributed solutions is limited to simulation-based methodologies, where virtualization technologies are used (e.g., virtual machines (VMs) and containers to distribute the control plane). In this context, largescale testbeds offer a platform to validate the applicability of an architecture to real-world network conditions. The Virtual Wall is one such large-scale generic experimentation facility for advanced networking research and testing. This work proposes a demonstrator for large-scale distributed SDN deployment using the Virtual Wall. It provides a thorough description of the steps involved to deploy experiments, by evaluating the scalability of a hierarchically distributed control plane.

2012 SC Companion: High Performance Computing, Networking Storage and Analysis, 2012

Data sets in e-science are increasing exponentially in size. To transfer these huge data sets we need to make efficient use of all available network capacity. This means using multiple paths when available. In this paper a prototype of such a multipath network is presented. Several emerging network technologies are integrated to achieve the goal of efficient high end-to-end throughput. Multipath TCP is used by the end hosts to distribute the traffic across multiple paths and OpenFlow is used within the network to do the wide area traffic engineering. Extensive monitoring is part of the demonstration. A website will show the actual topology (including link outages), the paths provisioned through the network and traffic statistics on all links and the end-to-end aggregate throughput.

Proceedings of the …, 2005