“Multipath TCP has several use cases, including smartphones that can use both WiFi and 3G, or servers that can pool multiple high-speed interfaces.”
I started building a home-brew application-level link sharing system once. When I realized I was basically reinventing TCP, I quit. If this multipath technique becomes commonplace, it will be awesome.
One warning though: it’s really easy to overlook when one of the links is broken. Without good diagnostics, you can be running on just the one remaining link until it, too, fails and then you’re troubleshooting multiple problems at once. It’s like RAID in that way.