ICX Switch

Switch behavior as defined by the IEEE standards is to "detect" and "classify" the devices attached to the Ethernet ports (RJ45). The first stage is detection and the method of detection is based on impedance and current measuring. This method is well defined by the standards, and Ruckus ICX switches follow these standards faithfully.

Once the attached device is "detected" as a valid PD, the second stage is to "classify" the PD as per the PoE classes defined by the 802.3af, 802.3at, and 802.3bt standards. The classification is achieved by a method similar to the detection—a series of one, two, or five events (current measuring) but with different time periods, voltage, and amplitude. The combination of events and current values in the PD signature allows the switch to identify the PD class.

PD Detection and Classification

This is hardware negotiation as in detection and classification. Once the negotiation is completed, a PD receives the classified amount of power: classes 0, 1, 2, 3, 4, 5, 6, 7, or 8 as defined by the standards (refer to Proprietary and Industry Specifications). Once the PD is booted up and begins running its application software, it can utilize LLDP (if supported) to further negotiate a more granular amount of power required by the PD to optimize its performance.