Welcome to this second issue of Multipath News.

Feel free to send suggestions or any feedback to multipath-news@tessares.net or through our online form.

This post summarises the main discussions on the mptcp-dev and IETF multipathtcp mailing list and the recent scientific articles on Multipath TCP.

IETF multipathtcp mailing list

The multipathtcp mailing list has been pretty quiet during the last month. Francois Finfe sent a question related to the MP_FASTCLOSE option. This option is used to quickly terminate a Multipath TCP connection. When a host needs to quickly stops an ongoing Multipath TCP connection, it sends this option inside an ACK segment over one subflow and a RST segment over the other subflows. Francois explained that if the ack carrying the MP_FASTCLOSE option is lost, it needs to be retransmitted as specified in RFC6824, but this segment does not allow firewalls that do not understand Multipath TCP to detect the termination of the subflow and release their state. It is likely that a compromise to solve this issue will be to allow the host to send a RST after three unsuccessful retransmissions of the MP_FASTCLOSE option . This discussion continued in the mptcp-dev mailing list as well.

The mptcp-dev mailing list

38 messages were sent on the mptcp-dev mailing during the last month.

Christoph Paasch sent a patch that fixes an issue with the creation of TFO sockets.
Hong Tran Viet proposed a virtual box image that includes a modified version of iperf3 that allows to perform measurements with MPTCP on any Linux or MacOS box. The vagrant config and detailed instruction for the experiment are available at https://github.com/hoang-tranviet/mptcp-vagrant/
Kristian Evensen has proposed a new version of multi network manager . The code is available at https://github.com/kristrev/multihomed-routing
Markus Jungblut has proposed a simple Apache module that allows to detect whether an incoming connection is a Multipath TCP connection or not. He uses this module on the http://mptcp.femasrv.de server which can also be used to test Multipath TCP connections.
Christoph Paasch sent a patch to correct an issue in the scheduler.
Sebastien Barre sent a patch that solves an issue with zero-windows.
Finally, while editing this issue of the Multipath news, Christoph Paasch announced the new stable 0.92 release that builds on Linux kernel 4.4. Christoph’s email is copied below so that you have all the detailed about this new release : https://multipath-tcp.org/pmwiki.php?n=Main.Release92

What is new in this release?

The MPTCP v0.92 release is based on the Linux Kernel Longterm Support release v4.4.x. Its new features compared to the v0.91 release are:

Support for selecting an MPTCP scheduler through the socket-option
MPTCP_SCHEDULER. (By Per Hurtig)
Support for selecting an MPTCP path-manager through the socket-option
MPTCP_PATH_MANAGER. (By Per Hurtig)
Allow recreating subflows after timeout through the module parameter.
Get detailed information on the state of subflows with the MPTCP_INFO
socket-option.

For details on how to use the socket-options and module-parameter, visit https://multipath-tcp.org/pmwiki.php/Users/ConfigureMPTCP.

There are now also Amazon AWS AMIs available with v0.92 pre-installed as well as instructions for GCE (http://multipath-tcp.org/pmwiki.php/Users/AWSGCE).

This release includes a total of 70 commits.

Contributors (ordered by number of commits)

Christoph Paasch (Apple)
Per Hurtig (Karlstads University)
Matthieu Baerts (Tessares)
Benjamin Hesmans (UCLouvain)
François Finfe (Tessares)
Tim Froidcoeur (Tessares)
Sébastien Barré (Tessares)

Scientific articles

In http://ieeexplore.ieee.org/abstract/document/7925844/, Wang et al. propose a variant of the Multipath TCP scheduler and test it by using simulations with an old ns-2 module.

In Primary Path Effect in Multi-Path TCP: How Serious Is It for Deployment Consideration?, S. Chattopadhyay et al. present a few measurements that analyse the impact of the characteristics of the initial subflow on the performance of a Multipath TCP connection.

In SDN-based Data Center Networking with Collaboration of Multipath TCP and Segment Routing, J. Pang et al explore with simulations the benefits that can be obtained by combining Multipath TCP with Segment Routing.

In On the Path Management of Multi-path TCP in Internet Scenarios Based on the NorNet Testbed, K. Wang et al. present a series of measurements conducted with Multipath TCP over the NorNet testbed.

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