Switch seamlessly between WiFi and Cellular with Multipath-TCP
asked 2015-04-05 18:54:54 +0200
Multipath-TCP is an extension to TCP that allows the parallel usage of multiple Internet connections. There are two use cases: First, you can use WiFi and Cellular (3G/4G) in parallel to get more speed, but even more interesting for a mobile phone is that Multipath-TCP can switch connections seamlessly. This means, when you walk out of range of your WiFi, all Multipath-TCP connections will just continue (instantly!), rather than break and probably getting reestablished after a while.
Apple uses this technology for "Siri", but not for Web browsing and apps.
In order to use Multipath-TCP, both the sender and the receiver have to support it, so it won't work with most servers out there. However, Jolla could provide a proxy server for Multipath-TCP connections. Also, since the Jolla community is quite technical, people could also set up their own proxies. Of course, regular TCP connections are still possible, since Multipath-TCP recognizes automatically if the other host supports it as well, otherwise it falls back to regular TCP.
Multipath-TCP is already implemented for the Linux Kernel, but not yet integrated into the official upstream kernel. The source code (and some precompiled kernels, including Android builds) can be found here: http://multipath-tcp.org. The development is mostly driven by the University of Louvain, accompanied by standardization in the IETF (RFC 6824). It is still an "experimental" Internet standard, although it's already very stable and "production ready".
Generally, applications do not have to be modified at all, the whole "work" is done by the kernel, therefore Multipath-TCP works automatically with any application (that uses TCP).
In addition to be a very unique feature that Jolla could provide for its users, Multipath-TCP would make the Jolla Smartphone and Tablet a very interesting platform for researchers.
just bringing back to attention after 5 years. :)
Sounds nice, does Jolla's chip support this?
simo ( 2015-04-05 19:14:13 +0200 )editThis would be a great feature
Mannix63 ( 2015-04-05 19:28:00 +0200 )editThis does require the other end (the server) to also support Multipath TCP. That might ofc be okay if one wants to setup a server in the cloud for something.
An alternative way of getting seamless fail over could be OpenVPN. As long as the server allows roaming clients(it does that by standard).
slaveriq ( 2015-04-05 19:29:51 +0200 )editEven if OpenVPN can hold the TCP connections intact it is not really an alternative as long as the tunnel itself consumes traffic to check if it's still alive (see OpenVPN option --keepalive). Disabling or setting keepalive timings to a high setting is not really an option for a stable tunnel. On the other side: short timings give more reliability but are very bad for a battery powered device. Personally I'm a huge fan of OpenVPN. However I doubt that it can replace technologie like multipath TCP
ibins ( 2015-04-05 19:41:07 +0200 )edit@simo, since Wifi tethering works fine with Jolla, I think there should be no limitations from the chipset.
Mario ( 2015-04-05 19:51:53 +0200 )edit