Cisco ASR 1000 series routers are popular as internet edge device. One of the functions ASR 1K provides is NAT deployed to conserve public IP space. For these ISPs keeping a log of NAT translations is a regulatory compliance called IPDR (IP Data Record). Trisul Network Analytics IPDR helps ISPs meet this compliance requirement.
This note explains how you can configure NAT logging on ASR
Cisco recommends that you use the purpose designed NetFlow mechanism rather than other methods like SYSLOG.
It is as simple as a single command. You do not need to enable it on a interface by interface basis unlike plain NetFlow
ip nat log translations flow-export v9 udp destination 10.17.17.17 2055
Where 10.17.17.17 is the IP Address of the NetFlow collector.