Karthick -
May we assume this is a 7-mode environ ?
You want iscsi to be licensed of the other controller, as well as following all of the other best practices for ha.
There's no need to configure igroups or any lun mappings on the partner controller.
There are plenty of best practice docs for various environs you can find by running a search on mysupport.netapp.com.
I hope this response has been helpful to you.
At your service,
Eugene E. Kashpureff, Sr.
Independent NetApp Consultant, K&H Research http://www.linkedin.com/in/eugenekashpureff
Senior NetApp Instructor, IT Learning Solutions http://sg.itls.asia/netapp
(P.S. I appreciate points for helpful or correct answers.)