Oracle Database Discussions

Hi,

I am working on a web application which requires 3000 concurrent users as a part of the NFR and almost all of them would trigger operations which would require DB hits. Hence my Oracle server (10g) needs to support at least 3000 sessions. I checked the value in the V$parameter. Currently the value for sessions and process is set to 170.

I guess to increase the value i would need to change it in the init ora file and restart the DB. I have the following doubts -
1. What would be the basic system configuration (for the server machine) to support 3000 sessions?
2. What are the other related parameters which need to changed? What values need to be set for the same and how do we calculate the same. Is there any model which can be used for calculations purposes.
3. Are there any in built mechanisms supported by Oracle to handle such high load? I presume there should be available and i am blissfully unaware about of it !

Request you to kindly guide me accordingly. Any help / pointers are greatly appreciated !!

Thanks & Regards,
Sriram