GSM1010M Gigabit Converter
17
connected to the remote MA device, notifies the GSM1010M and cuts off the TP link of
Master Unit, alerting in real time the switch/router of the subscriber failure.
All this is performed without disrupting the main F/O link, thus ensuring on-going control
of the remote device (CPE) via MA.
It should be noted that if the TP port link of the GSM1010 Master Unit (normally
connected to a switch/router TP port) has failed, the SLE will cut-off the TP port of
the remote MA device, providing in this manner an optimal bidirectional safe
operation.
Thus SLE has in effect two modes of operation:
Downstream SLE mode:
link failure of the GSM1010M TP port will cause the
disconnect of the TP port of the remote MA device (GSM1010MA)
Upstream SLE mode:
remote MA device link TP port failure (GSM1010MA) will cause
the disconnect of the GSM1010M TP port.
The SLE commands are implemented from the management.
Again it must be emphasized that this extensive set of features is obtained
only if MA
enabled devices are installed at both ends of the link and the MA management
Is active and operative.
Note: When both SLE and LST are enabled (LST OFF mode), the SLE will
override the LST mechanism if a TP link (at the GSM1010M) or at the input port
of remote MA device has failed. On the other hand, if the main F/O link is
disrupted, the LST will take over from SLE and execute the required actions.
When the LST takes over, the FEF mechanism will also operate and execute the
FEF operation according to the explanation reported in section 9.
During normal network operation, it is recommended to activate the SLE mechanism.
(Enable Downstream and Upstream modes through the management).
Users who do not require real time alert (Fault Propagation) upon a failure from one
Network Device to the other Network Device should set both the LST commands of both
converters to LST ON mode of operation (via the management)
Use and operate the LST (in TEST mode) in order to determine and locate a failed
Link segment.
Users requiring real time alert (Fault Propagation) upon a failure may define one direction
of alert, or both directions. In this case the LST commands are set to LST OFF mode.
Notes:
When LST is OFF (and SLE ON or OFF), it will neutralize the FEF feature
and if one of the F/O line is disrupted, the LST in this case will cause the disconnect
of the entire link segment (both Link/Act LEDs of FO and TP ports are DOWN)
On the other hand, if the LST is set to ON at both interconnected devices, and one
of the Fiber line is disrupted, then in this case the FEF mechanism will intervene
and cause the disconnect of the FO links only as explained in section 9 (FEF feature)
