Two same subnets in difrient location

Hello. Our company is currently undergoing a network migration. One of the goals is to place two identical subnets in different locations. In one location, there will only be a server, and in the other — hosts that need to communicate with that server. Is there anyone who can help me configure this or at least outline what needs to be set up? I should also mention that the communication must take place without the use of VPN or VLAN. I just need configure Mikrotik side. Other Administrator will configure Cisco side.
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Check this: http://forum.mikrotik.com/t/1-1-nat-dnat-configuration-help/182840/1

An alternative (and simple) solution: a dedicate “bridge” link, bridging the two switch domains.