Multiple server instances for multiple scenes in Mmo game?

We're start working on our Mmo game with Unity Unet
For now, We can let players log in and do stuff (killing/grinding) in one specific scene (Server scene is what it called I guess).
But for multiple scenes , We found that people suggest to have multiple server for scenes as Unet currently can handle one on same time. So forest server/desert server/town server must be seperated.

So here's our question.

1. Does player need to disconnect from current server and join new server in order to change map.
2. If #1 is true, could you pls suggest the way to do that by code.
3. Which properties can use to distinct each server so player can freely join (Network Port,Hostname,Etc.)

Thank you very much in advance.

 

you can see how its done here: https://github.com/alvyxaz/barebones-masterserver/wiki

 

the Barebones proj is REALLY good