Allied Telesis AT-MC104LH - Manual (Page 18)

Chapter 1: Overview
8
MissingLink
The MissingLink feature enables the fiber optic ports on the media
converter to pass the “Link” status of their connections to each other.
When the media converter detects a problem with one of the ports, such
as the loss of connection to an end-node, the media converter shuts down
the connection to the other port, thus notifying the node that the
connection has been lost.
For example, if the twisted pair cable to the 100Base-TX port on the
media converter were to fail, the media converter would respond by
dropping the link on the 100Base-FX fiber optic port. In this way, the
media converter notifies the end-node connected to the fiber optic port
that the connection on the twisted pair port has been lost. If the failure had
started with the fiber optic cabling, the unit would drop the link to the
twisted pair port.
The value to this type of network monitoring and fault notification is that
some hubs and switches can be configured to take a specific action in the
event of the loss of connection on a port. In some cases, the unit can be
configured to seek a redundant path to a disconnected node or send out a
trap to a network management station, and so alert the network
administrator of the problem.
Note
The MissingLink feature is disabled when you perform a link test
with the Link Test/MissingLink button. Consequently, to ensure that
the MissingLink feature is activated on the media converter, always
set the button to the M/L ON (IN) position during normal network
operations.
Auto-Negotiation Button
The Auto-Negotiation (A/N) button, located on the front panel of the
AT-MC101XL, AT-MC102XL, and AT-MC103XL/LH, enables and
disables the Auto-Negotiation feature (IEEE 802.3u) of the media
converter. The media converter uses Auto-Negotiation to determine the
duplex mode of the ports. The duplex mode refers to the manner in which
an end-node sends and receives data on the network. An end-node can
operate in either half- or full-duplex mode. A node operating in half-duplex
can either send or receive data, but not both at the same time. An end-
node operating in full-duplex can send and receive data simultaneously.
The best network performance is achieved when an end-node can
operate in full-duplex mode.