Alcatel-Lucent 9500 MXC, Руководство пользователя

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9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. IV-8-9
• A subordinate space diversity link operates independently of the ring operation.
Specifically, a wrapped ring link does not inhibit normal 1+1 operation of the
space diversity link.
Figure 8-1.
Switch Management Heirachy: SD + SD Subordinated Links
Figure 8-2.
Switch Management Heirachy: SD + 1+0 Link
• Normal space diversity online Tx and/or Rx switching remains enabled when
the ring is wrapped.
• A silent transmitter switch
4
is initiated when both far-end receivers are in
path-fail alarm, and the link has been wrapped for not less than 5 seconds.
• If the link failure is due to a path fade, the silent transmitter command from
the far-end(s) will not be received at the local end(s), meaning no Tx switch
will occur.
• If the link failure is due to a Tx failure, the silent transmitter command from
the far end will initiate a switch to the standby Tx at the local end (the
secondary RAC is the default standby Tx).
RING
Space
Diversity
Space
Diversity
RAC RAC RAC RAC
RING
Space
Diversity
RAC
RAC
RAC
A ring wrap occurs when the path provided by the space diversity link fails, or a
Tx or Rx online switch event occurs on the space diversity link, or both space
diversity receivers trigger a demodulator not locked alarm.
4
A silent transmitter switch is designed to prevent an undetected transmit failure from causing a link to go
down indefinitely.