Can all the upstream freq. be the same as long as different ports are used to recive them form the different nodes? And the load balanced ports have to have different freq.?
For SP/cable design advice, your best choice would be talking to a Senior SE or Consultant from your Cisco sales office.
Can all the upstream freq. be the same as long as different ports are used to recive them form the different nodes?
Yep, that is correct. Check out our document on frequncy stacking. Even though its not exactly what you're doing there's good info there:
http://www.cisco.com/en/US/partner/tech/tk86/tk804/technologies_white_paper09186a0080232b49.shtml
And the load balanced ports have to have different freq.?
Yep, that is also correct.