ZyXEL Communications ES-315 - V3.70 User Manual page 54

Chapter 6 Basic Setting
Table 11 Basic Setting > Port Setup (continued)
LABEL
Speed/Duplex
Flow Control
802.1p Priority This priority value is added to incoming frames without a (802.1p) priority queue tag.
Apply
Cancel
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DESCRIPTION
Select the speed and the duplex mode of the Ethernet connection on this port.
Choices are Auto, 10M/Half Duplex, 10M/Full Duplex, 100M/Half Duplex and
100M/Full Duplex.
Selecting Auto (auto-negotiation) allows one port to negotiate with a peer port
automatically to obtain the connection speed and duplex mode that both ends
support. When auto-negotiation is turned on, a port on the Switch negotiates with the
peer automatically to determine the connection speed and duplex mode. If the peer
port does not support auto-negotiation or turns off this feature, the Switch determines
the connection speed by detecting the signal on the cable and using half duplex
mode. When the Switch's auto-negotiation is turned off, a port uses the pre-
configured speed and duplex mode when making a connection, thus requiring you to
make sure that the settings of the peer port are the same in order to connect.
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 IEEE802.3x flow control in full duplex mode and backpressure flow
control in half duplex mode.
IEEE802.3x 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.
See Priority Queue Assignment in
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.
Click Cancel to begin configuring this screen afresh.
Table 9 on page 50 for more information.
ES-315/ES-315-F User's Guide