Allied Telesis AT-S97 - Manual (Page 72)

Chapter 5: Port and Module Commands
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ml Specifies the MissingLink™ mode.
sml Specifies the Smart MissingLink mode.
Privilege Levels
Administrator and read-write.
General Description
This command sets the operating mode of the media converter channels
on a media converter module. Different channels on the same media
converter module can be set to different operating modes. None of the
operating modes interfere with the flow of network traffic through the ports
of a channel and can be used during normal network operations. To view
a channel’s current operating mode, refer to “SYSTEM SHOW
INTERFACE” on page 90.
Description of the Link Test Mode
Contrary to its name, the Link Test operating mode does not test anything.
Rather, it simply reflects the link status of a port on the port’s Link LED and
in the SYSTEM SHOW INTERFACE command. For example, when a port
in a media converter channel running in this mode has a valid link to a
network device, its Link LED will be on and its status in the SYSTEM
SHOW INTERFACE command will be Online. Conversely, when a
channel port operating in this mode does not have a link, its Link LED will
be off and its status in the SYSTEM SHOW INTERFACE command will be
offline.
This mode is typically used when the network devices connected to the
ports of a channel cannot take advantage of the features of the
MissingLink mode, or when you want to use the Link LEDs or the
SYSTEM SHOW INTERFACE command to troubleshoot a network
problem with a channel. This operating mode is also useful after the
installation of a media converter module to verify whether the ports of a
channel have established a link with a network device.
Description of the MissingLink Mode
In the MissingLink mode, the two ports of a channel share their “link”
status with each other so that both ports of a channel and, consequently,
the network devices connected to the ports, are always aware of a change
to the status of the link of the companion port in a channel. When a
channel in the MissingLink mode detects the loss of a link on one of its
ports, it replicates the loss on the companion port in the same channel by
disabling the transmitter on the companion port. This notifies the network
device connected to the port of the loss of the link on the other channel
port. Without the MissingLink mode, a network device connected to a
channel port would be unaware of a loss of a link on its companion port in