Thank you Francesco.
Basically, I want to set up a lab first, client/server scenario:
Client --Priv IP 10.1.0.0 /16--switch---FW===P2P [outside]===FW----switch- Private IP 10.2.0.0/16 ---Server.
I would like to configure the outside network by complying with RFC 6598 [Address Space, 100.64.0.0/10] .
What interfaces do get IPs from these RFC6598 assigned and what routes are required to be implemented?
on a side note, in order to use CGN NAT, your router needs to support the 'ip nat settings mode cgn' global command. I am not sure which routers and/or IOS versions do support that, it doesn't work in GNS3.