During Tuesday maintenance Phil and myself tried to replace the Cisco 3560 switch in the CER for a Fiber-store FS S5500-48T8SP, after we migrated all devices plugged on the Cisco switch to the new one, the switch became unstable loosing connectivity and dropping all connections including the optic fiber link to the core switch. After several reviews of the configuration both at the Core and at the local switch was determined that further load test should be done to this new hardware. As a result we rolled back to the Cisco 3560.