MikroTik

I have a business looking to purchase wireless capacity from me. I don't want his lan to be part of mine so I don't just want to bridge it. I wan't to give him 10mbs. Do I just create a virtual interface with a /30 address for the point-to-point to the router on his end? Also how would I secure the link so no one else can connect to it? So this is what it would look like.
router>>>switch>>>RBSXT>>>RBSXT>>>customer router

Thanks.

-Use the SXT in bridge mode
-disable defaullt authenticate
-create an access-list rule with the client SXT's MAC-address and a true signal intervall.

If you use L2 manageable switch and using vlans, you can encrypt your data with PPPoE.