3Com 2226 PWR User Guide - Page 43

Viewing Statistics 43 3 Click Apply to save the PoE settings for the port. To configure the PoE settings of another port, click the port number from the PoE Configuration screen. Planning Power Budgets As you connect more PoE devices to the Switch, you may need to calculate your power budget. Planning a Power Budget The Switch can supply a maximum of 15.4 watts to any of its 24 10/100 ports, provided that the total power delivered does not exceed 180 watts. When you plan your network, you need to calculate the maximum power that you will need to ensure that the Switch is not expected to supply more than its maximum capacity. To calculate the power budget for the Switch, add together the power requirements of the devices that will be connected at any one time. The power requirements of PoE-compliant devices can be found in the documentation supplied with the device. If the maximum power for the Switch is exceeded, the Switch follows the following rule: ■ Any device connected to a lower port number will take priority over a device connected to a higher port number. If the Switch needs to remove power from a device, it will remove power from the highest numbered port. When the Switch is power-cycled, it will supply power to the ports starting with the lowest numbered port first. Implementing a Power Plan If the total power required by your PoE devices is less than the Switch's power budget, then you can guarantee power to every port. If the total power required by your PoE devices is more than the Switch's power budget, then you will not be able to guarantee power to all devices. If this is the case, you may choose to: ■ Add additional PoE switches - This will enable you to guarantee power to each port on the Switch that supplies a Power over Ethernet device. The remaining ports can be used to supply networking to those devices that are powered by other means. ■ Prioritize PoE devices - Since the Switch supplies power to the lowest numbered port first, you should connect your PoE devices in order of importance, the most important device being connected to the lowest numbered port. By monitoring power consumption and checking if any devices have been refused power, you can decide whether additional PoE switches are required. Viewing Statistics The Statistics screen shows a summary of traffic statistics for all ports, as shown in Figure 22.