Hi,
In local database you can see the remote tables from remote database as thay would be in your local database - this is federated database.
If you are trying to compare two tables from two DB2 databases then all the products you need is DB2. If you would like to compare two tables from diffrent databases like DB2 and Oracle you need product IBM Information Integrator. As I see you probably have DB2 on bouth servers so DB2 is only what you need.
At IBM documentation site there is a book
Federated Systems Guide. Download it and read it.
Try to configer it through GUI Control Center. At database level there is folder "Federated Database Objects". Right click on it and...
Hope this helps,
Grofaty