Thanks for your update.
We are installing Grid Infrastructure for standalone server on AIX machine. When i checked the netca trace file i can see that installation was looking for port 1521. As we installed oracle 10g on the same machine port 1521 is being used by 10g database.
You can either create a new listener with a different port and use that listener with the new database.
Or you can use the existing listener with the new database (you don't have to create a new listener.ora file for the new database home).
10g database can register itself with 11g listener, so you can just shut down the 10g listener. In this case the listener will be managed, monitored and automatically started/stopped by Oracle Restart (aka Grid Infrastructure for standalone server).