I am in the process of upgrading Avaya/Cajun P334T Edge switches with Cisco 3750 switches. The Core switch is an HP Procurve 5308Xl switch with fibre connectivity between the core and edge switches. The network is flat with all ports in the default VLAN, with no trunking, or spanning tree configured.
I am get no connectivity across the fibre backbone when the Avaya/cajun swithes are replaced with the Cisco 3750 switch. Both edge and core switches have LC mini gigabit ethernet fibre modules.