I am upgrading the existing layer 2 switched (HP) network. I want to use two CAT 6506 switches for the core/distribution layer and uplinking these core switches to HP layer 2 switches in the closets by gigabit fiber link. There are 22 switches in the closets. Can someone suggest what should be the CAT 6506 specifications and what sort of module do I need for these switches. How can I provide gigabit connectivity between access and core/distribution layer. Thanks in anticipation.