Allied Telesis AT-MC102XLPCI - Manual (Page 21)

AT-MC102XLPCI 100Mbps Media Converter Installation Guide
21
MissingLink & Link Test Features
The MissingLink & Link Test jumper (J5) on the PC board is configured at
the factory with the MissingLink feature enabled and Link Test disabled.
This section contains the following topics:
❒
MissingLink Feature
❒
Link Test Feature
❒
Configuring MissingLink & Link Test Features on page 22
MissingLink
Feature
The MissingLink feature enables the fiber optic and twisted-pair ports on
the media converter to pass the “Link” status of their connections to each
other. The AT-MC102XLPCI is configured for MissingLink at the factory
with pin 1 and pin 2 connected of jumper J5 (see Figure 4). When the AT-
MC102XLPCI detects that an active link has gone down on one of its
ports, it shuts down the link to its opposite port. The result is that the AT-
MC102XLPCI notifies the end node connected to the opposite port by
setting its link to go down.
This type of behavior is a form of network monitoring and fault notification
for the network device connected to the opposite port of the AT-
MC102XLPCI. Some network devices can be configured to recognize that
the loss of connection on a port and take a specific action in response to
this event. For example if the end node is a managed switch, it can be
configured to choose a redundant path as an alternative data path and/or
send out a trap to a network management station so that the network
administrator can be notified of the problem.
For example, if the twisted-pair cable to the 100Base-TX port on the media
converter were to fail and the link went down, the AT-MC102XLPCI 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. When the failed Ethernet path is repaired and the link is
re-established, then the AT-MC102XLPCI re-establishes the link on its
opposite port.
Link Test Feature
The Link Test mode provides a method of testing the connections between
the ports on the media converter and the nodes that are connected to the
ports. If a network problem occurs, you can perform a Link Test to
determine which port is experiencing a problem. This test allows you to
focus on the port and end-node where the problem resides.