I’m at the IETF in Seoul.

Korean attendee: Excuse me, could you explain the basic idea behind MPTCP? Is it for when you have two SIM cards, one 3G and one LTE, so you can share the load between the two?

Me: Kind of. You can use it like that, for getting more throughput on cell networks, but mostly I think it’s used for balancing between LTE and wifi networks. Not so much for extra throughput, but for failover, so if your wifi or LTE is connected and not working, it’ll use the other one right away, without having to wait for it to fail first.

KA: [blank look]

Me: Like, sometimes when you you're out of range but it still thinks it’s connected, or when the cell you're connected to loses connectivity for some reason...

KA: [Looks suspicious]

Me: That just never happens here, does it.

KA: Yes, if the connection didn’t work sometimes, people would be very angry.