The Cisco 550X Series is designed to deliver hardware redundancy at the lowest incremental cost. If power to the switch is lost (through loss of AC power or power supply failure), the switch will automatically, and instantaneously, obtain its power from the RPS. This switchover occurs so quickly that there is no loss in traffic or reboot of the device. Cooling fan redundancy is delivered through preinstalled N+1 configuration. A switch can fully support all its capabilities for the life of the product with only N fans. If one of the fans fails, the spare fan automatically takes over, without causing any downtime. The Cisco 550X Series provides an additional layer of resiliency with support for the Virtual Router Redundancy Protocol (VRRP). VRRP lets you extend the same resiliency that stacking provides for individual switches to complete network domains. By running VRRP between two stacks, you can instantly cut over from one stack to another in the event of a problem & continue operating even after a failure. Automatic power shutoff on ports when a link is down LEDs that can be turned off to save power Embedded intelligence to adjust signal strength based on the length of the connecting cable Smart fans in which fan speed is automatically adjusted according to switch temperature to decrease acoustic noise & save power