IP Subnetting Notes
For a WAN link you would use 255.255.255.252, which would give you for example 188.8.131.52 for a subnet address and 184.108.40.206 and 220.127.116.11 for each end and 18.104.22.168 as the broadcast address. The next subnet would be 22.214.171.124.
To calculate the number of address in a subnet mask you would subtract the final byte from 255 and add 1, ie 255 - 252 + 1 = 4 which is the number of address for that subnet mask. The reason for adding one is because the numbering range is 0 to 255 which actually gives you 256, hence the add 1. This works for all masks to. Then you get to reverse bit masking too. I have been meaning to write some simple rules to help with this but have been quite busy.