Multipath TCP inside the beast
One of the nice points about releasing open-source software such as the Multipath TCP implementation in the Linux kernel is that there are unexpected use cases. In early 2013, we were contacted by Niels Laukens who works for VRT, the Dutch speaking television in Belgium. He had been following the project and identified a nice use case. Journalists use more and more computers to prepare their articles, but also when they go off-site for interviews. Once the interview has been recorded, they often need to edit it locally before uploading it to the television services to broadcast it or place it on the web site.
For live videos, they often rely on dedicated satellite channels, but these are expensive and they need a large antenna. Such antennas are fine when an event is planned and they need a large coverage. However, there are many situations where they cannot send a large team to record interviews and short movies. To cover those cases, they have equipped a small “mini” that serves as a mobile studio. A single journalist can record an interview, edit it and then send it over the air. This last part is the most interesting one for us. Satellite links are expensive and there are many situations where it is difficult to use a satellite. 3G, 4G and Wi-Fi could help, but their performance differ. Asking each journalist to learn to select the best network to upload his work was not a feasible solution. Fortunately, Niels found the right solution with Multipath TCP. The mini is equipped with a simple Multipath TCP proxy that is attached to all the available networks. The journalist to use his/her regular laptop through the proxy to upload his/her movies via all the available connections. This is much faster and simpler than always moving the car to a location where the satellite works well.
VRT published a nice video of their mini that is internally called “The Beast” :