Oracle says you can register a target db (say T-DB) for the recovery catalog ( say R-DB which is on a seperate server) using RMAN.

(say JOHN is a user account having necessary privs for RMAN operations)

When we execute the command "RMAN target T-DB catalog JOHN/JOHN@R-DB"

Since R-DB and T-DB are on different servers, how will Oracle understand where the server and DB is located? Also, do we execute this command from the target server (T-DB) or from RMAN Recovery Catalog Server (R-DB)??

Kindly advise.