ZyXEL Communications ES-2024 Series, Руководство пользователя, Страница: 81 / 282

Chapter 8 Basic Setting
ES-2024 Series User’s Guide
81
8.8 PoE Status
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The following screens are available for the ES-2024 PWR model only. Some
features are only available for the Fast Ethernet ports (1 to 24).
Your Switch supports IEEE 802.3af Power over Ethernet (PoE).
A powered device (PD) is a device such as an access point or a switch, that supports PoE
(Power over Ethernet) so that it can receive power from another device through a 10/100Mbps
Ethernet port.
In the figure below, the IP camera and IP phone get their power directly from the Switch.
Aside from minimizing the need for cables and wires, PoE removes the hassle of trying to find
a nearby electric outlet to power up devices.
Figure 37 Powered Device Examples
Flow Control A concentration of traffic on a port decreases port bandwidth and overflows buffer
memory causing packet discards and frame losses. Flow Control is used to regulate
transmission of signals to match the bandwidth of the receiving port.
The Switch uses IEEE 802.3x flow control in full duplex mode and backpressure flow
control in half duplex mode.
IEEE 802.3x flow control is used in full duplex mode to send a pause signal to the
sending port, causing it to temporarily stop sending signals when the receiving port
memory buffers fill.
Back Pressure flow control is typically used in half duplex mode to send a "collision"
signal to the sending port (mimicking a state of packet collision) causing the sending
port to temporarily stop sending signals and resend later. Select Flow Control to
enable it.
802.1p Priority This priority value is added to incoming frames without a (802.1p) priority queue tag.
See Priority Queue Assignment in Table 9 on page 76 for more information.
Apply Click Apply to save your changes to the Switch’s run-time memory. The Switch loses
these changes if it is turned off or loses power, so use the Save link on the top
navigation panel to save your changes to the non-volatile memory when you are done
configuring.
Cancel Click Cancel to begin configuring this screen afresh.
Table 11 Basic Setting > Port Setup (continued)
LABEL DESCRIPTION