APs commonly receive power through an Ethernet backhaul cable connection to an upstream switch. This method is known as Power over Ethernet or PoE. When an AP first boots, it selects a power mode based on the available PoE protocols. The AP can start with PoE and move to PoE+ after a brief interval. It uses the selected power mode until it reboots.
PoE stability anomalies are related to PoE flapping and sudden changes in power draw. Data is presented over a 24-hour period, and includes date and time details.
The severity definitions for PoE anomalies are based on the average number of clients connected to an AP on a given day. If there are fewer than 10 clients, the anomaly severity is considered low. If there are 50 or more clients on a given day, the severity level is considered high. If there are between 10 and 50 clients, the severity level is considered medium.
Occasionally, poorly installed cabling or MDU closet wiring, lack of power on the upstream switch, or a failing power supply on either the AP or the switch might cause APs to cycle through power modes, while never reaching a steady state. There are three types of PoE stability anomalies:
The AP negotiates down to AF, even though it requires AT or a higher level for optimal performance and full capacity.
The AP switches PoE modes more than 10 times within a 24-hour period, indicating an unstable connection.
The AP spends less than 80% of its time operating in a single PoE mode, indicating an unstable connection.
To open the PoE Stability Anomaly panel, select a location (site), for which anomalies have been detected, from the table. To view more information about an anomaly, select the corresponding down arrow. The PoE Stability Anomaly panel includes the following information:
A description of the problem, including the anomaly type (SUB-OPTIMAL, FLIP, TIME, or a combination)
Best practices to resolve the anomaly
A graph showing the number of changes and the dates they occurred, color coded for severity
Note
The PoE Mode Changes graph appears for FLIP or TIME PoE anomalies, and for anomalies that are a combination of FLIP or TIME and SUB_OPTIMAL. The graph does not appear if the only wired or wireless PoE anomaly type is SUB_OPTIMAL.