Sort:  

Both. Hive is layer 1. Posts, comments are stored here. Hive, HBD and Hive Power as well as RC are also done here.

Hive Engine is layer 2, something built on top of engine. The custom LEO token is handled here.

Leo relies upon 2 separate 3rd layers as well which are: custom code written by the hive-engine team that handles sending tokens out for posts(this feature is implemented right in hive-engine as well, but the Leo team needs to migrate to it) as well as their own custom indexer which handles the stuff they do.

That means Leo infrastructure that Khal talks about is the third layers on Hive?

Thanks for the info though. And, why is HE down all the time lately?

Some engine nodes are going down, and most of the sites use those node. I recommend using beeswap, https://beeswap.dcity.io/.