Ticket number generation for trades

 
Hello,

I would like to find out more about the way the ticket numbers are generated for trades.
Are these numbers unique per client terminal or per EA instance?
If the EA is started and stopped multiple times, and in each run it creates multiple trades, will those trades get unique ticket numbers?
Also, if I select a trade that was closed say a week ago, would the OrderTicket() function return the ticket number of the trade as assigned at the creation time?

Best regards,
Levente
 
Ticket number is unique per whole trade server (for all clients)
Reason: