Bounce between Mobile Objects

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Hello,
I develop a game on Unity with fast balls bounce on another fast objects in movement (the term is : "Non-Deterministic" if i understood), like a Pong for explain simply but its not that at all... but same situation but very fast.
Then i need to know which solutions you advice for that ?
How to proceed and to configure ?
Any Tips ?
And mainly Could i use RPC.AllBufferedViaServer or RPC.AllBuffered ? for mostly synchronize results
Thanks you