Does google (assuming Spanner) really use Paxos across WAN? My understanding is, it does Two-Phase-Commit (across WAN) over fault-tolerant objects (located in

Does google (assuming Spanner) really use Paxos across WAN? My understanding is, it does Two-Phase-Commit (across WAN) over fault-tolerant objects (located in a Paxos Group). Paxos Group could span across Data-Centers, but there it just uses normal Multi-Paxos -- perhaps with some extra leader election tricks.