Mikrotik support /31 addressing across p2p links between 2 Mikrotik interfaces. This is useful for conserving address space. As you probably know, usually a subnet's network and broadcast addresses are unusable. That means for a p2p link, we need 2 x usable addresses - or a /30 which is a chunk of 4 addresses! So for every link we waste 2 valuable addresses. No good if you are using public address space and have a limited number. It's not so critical if you are using a private range obviously - but it does make it nice and tidy :)
In the above example, it uses 4 addresses -
We can split this into 2 x /31 by making the address of the local router the network address and the remote end the broadcast.
add address=10.20.20.12/31 interface=ether1 network=10.20.20.13 broadcast=10.20.20.12
add address=10.20.20.13/31 interface=ether1 network=10.20.20.12 broadcast=10.20.20.13
The network address should be set to the remote side IP address.
[EDIT] Note that this isn't great for OSPF networks. One side of the link won't be advertised into the ospf domain.