I have a mobile Linux server with two LTE connections to the internet, via different providers.
The mobile server also acts as a router for other devices, currently using masquerading on just a single LTE connection.
There is also a central Linux server, on high-speed internet connection.
I want to use both of the LTE connections redundantly, so that all internet-bound packets are sent via both LTE connections, via the central server.
What is the best way of achieving this?
I have considered using bonding, with Ethernet-over-IP to the central server on each of the LTE connections, but that seems wasteful.
Is there an equivalent of bonding, but at the IP, rather than ethernet, level?