Alcatel-Lucent 9500 MXC, User Manual, Page: 500 / 916

Chapter 8. Protection
Vol. IV-8-18 Alcatel-Lucent
(embedded) software.
5. The IDU designated as primary is default online for Tx and Rx providing the
primary and secondary IDUs are powered on at the same time
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.
6. In the event of a Tx switch (hot-standby and space diversity) the online Rx,
which controls the hitless Rx operation (diversity bus), is also switched to be
with the online Tx IDU. The reverse does not occur i.e. if the an online Rx
switch occurs, the Tx does not switch.
7. Tx switching is not hitless. Rx path switching (voting) is hitless (the least
errored Rx data stream from the two receivers is selected by the online Rx on
a block-by-block basis).
8. When a switch does occur, the link will stay with the online Tx and Rx until
forced to change by a subsequent alarm condition or a CT command.
9. Protection applies only to the payload and alarm I/O
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; auxiliary data is not
protected.
If auxiliary data is required it should be configured for the primary IDU at
each end of the link, which is the default online IDU. In the event of a
protection switch (to secondary IDU Tx or Rx), the link must be returned to
primary online to restore auxiliary data.
10. Alarm I/O is configured separately for each partner.
11. The two IDU partners must be interconnected with a protection cable and
Ethernet NMS cable before commencement of protection configuration, and
must stay in place subsequently to support protection switching and NMS
access.For the IDU 20x the interconnecting protection cable/ports are labelled
as ‘Expansion’.
12. Providing the protection cable is installed, only one IDU can be transmitting
(partner is Tx muted). This applies regardless of whether or not ‘Enable IDU
Protection’ has been selected in the IDU protection screens.
13. If the IDU which is acting as the hub
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for NMS interconnection is switched
off (-48 VDC supply removed), next-hop NMS connectivity will be lost.
• Before disconnecting the supply to one IDU of a protected pair, ensure
next-hop NMS connectivity is maintained by, if necessary, re-locating the
next-hop NMS cable to its partner IDU.
14. When installed with a single antenna, an equal loss coupler is recommended.
If an unequal loss coupler is used, bear in mind that one IDU has both its Tx
and Rx connected to the low-loss side, and the other IDU the high-loss side.
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Providing the primary IDU is powered on before the secondary IDU, or within 10 seconds of the
secondary IDU, the primary IDU will be default online. If the primary IDU is powered on later than 10
seconds after the secondary, the secondary IDU will be established as the online IDU.
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Alarm I/O remote actions are transported via the NMS.
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Connects its partner IDU and a co-located link or other NMS port for next-hop NMS.