Event Handler Question

I'm writing an isometric strategy game, and want to use some simple physics to allow the units on the game grid to bump into each other/walls/etc. The question is, what's the best way of communicating between server and client the positions of the units when physics things happen? Example: All physics is done server-side. When the client wants to move a unit, the client sends an event to the server requesting movement. The server then does physics stuff, moves the unit, then replies to the client with an event detailing the new position of the unit. Is this reasonable for normal bandwidth? If not, what's a better solution? I'm kind of stumped as to where to begin without knowledge of what's expected of the event handler.