Hi Reagan Benjamin,
Thanks for your information. I have studied the link which you mentioned. In this link
http://it.toolbox.com/blogs/sap-library/understanding-the-sap-system-instance-30172
it is given like like this - "In a case where you have more than one instances running on a single host, the port address numbers 3200 and 3201 are assigned in that sequence for subsequent instances." Can you clarify this sentence. I am not getting this. More than one instance running on a single host means, SAP is installed again on the same server, but as per my knowledge we can't install the same software twice in a system.