Enterasys Networks 700 - Manual (Page 59)

Managing the Module 2-39
The MultiSwitch 700 Device View
The Current Operational Mode settings indicate which of the available
operational modes is currently in effect. If Auto Negotiate is the selected mode,
the Current Operational Mode fields will indicate which mode was selected by
the link partner.
The Desired Operational Mode settings display the operational mode that is
currently selected for this port, and allows you to change the selection.
The following operational modes can be specified:
Speed
This field specifies a port speed of 10MB, 100MB, or 1000MB.
Duplex
This field specifies Half Duplex or Full Duplex mode for the port.
Flow Control
Flow control allows Ethernet devices to notify attached devices that congestion is
occurring and that the sending device should stop transmitting until the
congestion can be cleared. There are two commonly used methods of flow control:
Frame-based (operates on Full Duplex links) and Backpressure (operates on Half
Duplex links).
Ports set to Full Duplex mode have frame-based flow control, using pause
control frames. Frame-based flow control options are:
Symmetric The port is able to both receive and transmit pause control
frames.
Asymmetric RX This option appears only for Gigabit Ethernet ports. The port
will receive pause control frames, but will not transmit its own.
Asymmetric TX This option appears only for Gigabit Ethernet ports. The port is
capable of sending pause control frames, but will not
acknowledge received pause control frames.
Disabled Disables flow control on the port.
Auto Negotiate Ports configured to operate in auto negotiation mode will only
use pause control frames if the negotiation process determines
that the link partner supports them. Both ends of the link must
support auto negotiation and a common mode of operation.
Ports set to Half Duplex mode use Backpressure flow control. Backpressure flow
control simply asserts the carrier sense signal out the port causing the device
transmitting to detect a collision, stop transmitting data, and send the jam signal.
Backpressure flow control options are enabled or disabled.