What is the difference LTM+DNS service and CGN+DNS service?

Hi All,

 

As far as I know, I can use LTM with the DNS service license or CGNAT with DNS services license to deploy NAT64/DNS64 features.

 

What is the difference of the functionality between on the LTM with DNS service and CGN with DNS service?

 

Please forgive my ignorance.

 

Thanks,

 

Iom.