Allied Telesis AT-MMC1000/SP, Руководство по установке

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AT-MMC1000 Mini Switching Media Converter Installation Guide
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Smart MissingLink™ (SML)
If one of the Ethernet connections to the media converter loses link, the
Smart MissingLink™ (SML) feature allows you to determine which port still
has a valid connection and which port requires troubleshooting. The value
to this type of network monitoring and fault notification is that you can
quickly determine which media converter port has failed and troubleshoot
the specific area where the problem is occurring.
When the media converter detects a loss of connection on one of the
ports, the port’s L/A LED is turned off. At the same time, the media
converter causes the opposite port’s L/A LED to blink while simultaneously
turning OFF that port’s Ethernet connection to its end node. This occurs
even though the properly operating port had a valid connection before the
failure occurred: The reason for this is so that its end node is notified that
the data path has been compromised, and immediate action is required.
For example, if the network connection to the media converter’s
twisted-pair port fails (as shown in Figure 7 on page 24), the FIBER P2 L/A
LED blinks slowly while the fiber port’s link is turned OFF. The COPPER
P2 L/A LED is turned OFF, indicating a failed connection on the
twisted-pair port.
If the failure had started with the fiber-optic cabling (as shown in Figure 8
on page 24), then the COPPER P2 L/A LED would blink slowly, and the
FIBER P2 L/A LED would turn OFF.
Guidelines
Here are a list of guidelines for enabling SML on media converters:

SML is supported when two media converters are connected
back-to-back.

The AT-MMC1000/SP media converter must be connected with
another AT-MMC1000/SP media converter or an
AT-MMC2000/SP media converter.

The SFP modules installed on the two media converters must be
the same model.

You must disable SML on the AT-MMC1000/SP media converter if
the other media converter is not an AT-MMC1000/SP or
AT-MMC2000/SP media converter.
SML Example
Scenarios
Following are example scenarios with two SML enabled media converters
connected back-to-back (bookend mode).
Figure 6 on page 24 shows media converter and end node L/A LED
behavior with SML enabled under normal conditions.