I was planning to implement redundancy at core level by using once C4506 and a 3750G switch using HSRP and the trunks from various distribution layer switches would be connecting each of these switch. Primary trunk to C4506 and the copper uplink (secondary) to the 3750G. For which I also want to enable Rapid-PVST mode. So that for half of the vlans, C4506 would be the root bridge and for next half 3750G would be the root bridge. Please let me know will the CPU utilization a concern here. If so how can that be reduced? Let me know if through any design we can acheive the redudancy.