The Motivation Behind the Fast Paxos Protocol

Physicists put a limit on how quickly you can communicate across the globe. So I imagine there are added challenges to having a consensus protocol when we scale up that far and know that replication lag is kind of relative to location. The idea really stems from what if you could use your nearby replicas rather than going far and through the ocean links to reach the remote leader? And that is sort of what fast Paxos does. It basically says that you can send the request to the node that is closest to you. If it is not able to reach agreement, which can happen if multiple nodes are trying to propose client requests at the same time, then you fall back to the leader.