MMO Tower Defence, Network Traffic

I want to make MMO Tower Defence game with Smartfox as network asset. Because I want to implement a ranking system, the server needs to handle the game logic and database management. My question is how can I minimize traffic in a tower defence game. I have a lobby where people can create games, and people can join. Lets they 10 players are in this game. Every tower shoot etc… needs to be authorized and send to every client in this game. When many players playing this game, the traffic will be very high (because of many towers u can build). How can I solve this problem? Or am i thinking wrong?

Can towers be manually controlled or do they operate on their own? If can be controlled it gets much more complicated, if they just go on their own then its a bit easier.

Just have to so that when a player creates a tower, they don’t own the network view any more, the server does. The server will do all the shooting logic of the tower and it will relay that to all the players. Though it must remember its ‘owner’ so that it can give kill accreditation if you need that.

In tower defences the players are pretty much watching the game and their only input is placement of towers of special abilities they use.