ZyXEL Communications MES3500-24 User Manual

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Chapter 8 Basic Setting
MES3500-24/24F User’s Guide
96
Speed/Duplex
Select the speed and the duplex mode of the Ethernet connection on this port. Choices are 
Auto10M/Half Duplex10M/Full Duplex100M/Half Duplex100M/Full Duplex and 
1000M/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, thus 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 
 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 13   
Basic Setting > Port Setup  (continued)
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