Senthil:
I am currently working through the exact same issue you are experiencing. The insight I can provide you right now is that the IPs should be on different subnets in order to avoid address resolution problems. In regards to the ISR not being triggered, I believe you must change which accChannelNum is being used for the second interface in the setupRx function. For instance, my code initializes accChannelNum to be PA_ACC_CHANNEL_NUM for the first interface, and PA_ACC_CHANNEL_NUM + 8 for the second interface. This 8 stems from usable accumulator channels on 6678 core 0. If you are using say, a 6670, use + 4. Additionally, I believe you have to set a different event ID for the other interface and register the ISR handle with this event as well. I simply chose the eventId to be PLATFORM_ETH_EVENTID+1.
I have not had a chance to properly test this but I believe it is in the right direction. I should have more information in the next several days.
Sincerely,
John Demery