Multipath TCP: an overview

But I think I understand the reasons why this is not so simple, even if we're assuming widespread IPv6 adoption. Namely it would probably require widespread use of dynamic mesh routing protocols.

If you start with the assumption that the IP layer would need a consistent way of "addressing" a single node moving across connections - a single "IP Address" if you will, you've then got to remember that traditional internet routing works through the majority of IP address structure being hierarchical with respect to routing. This allows most nodes to keep their routing tables fairly small and static.

Essentially, you'd need a routing protocol that could deal with what was your broadband provider's IP suddenly coming under the hierarchy of your mobile provider's network. And the currently used routing protocols simply can't deal with that.