ZyXEL Communications GS1920v2 Series User Manual page 208

Table 100 PORT > Port Setup > Port Setup (continued)
LABEL DESCRIPTION
Speed/Duplex Select the speed and the duplex mode of the Ethernet connection on this port. Choices are
Auto, 10-an (10M/auto-negotiation), 10M/Half Duplex, 10M/Full Duplex, 100-an (100M/auto-
negotiation), 100M/Half Duplex, 100M/Full Duplex and 1G/Full Duplex (Gigabit connections only).
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, therefore requiring you
to make sure that the settings of the peer port are the same in order to connect.
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 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.
802.1p Priority This priority value is added to incoming frames without a (802.1p) priority queue tag. See Priority
Queue Assignment in
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.
Chapter 34 Port Setup
Section 44.2 on page 264
GS1920v2 Series User's Guide
208
for more information.