Alcatel-Lucent 9500 MXC, User Manual, Page: 165 / 916

9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. II-3-71
NPC
The NPC provides a protection option for the NCC with backup for TDM bus
management (bus clock), and power supply. One NPC can be installed per INU/
INUe.
The NPC protects tributary and auxiliary traffic. Alarm I/O is not protected
• Protection switching is not hitless for a TDM bus clock failure. Restoration is
within 100 ms, during which time all traffic on the node will be affected.
• Protection is hitless for a power supply failure. If the NCC converter or one of
its supply rails fails, the NPC will take over without interruption. And vice
versa.
When the TDM bus clock has switched to NPC control, it will not automatically
revert to NCC control on restoration of the NCC. Return to NCC control requires
either withdrawal/failure of the NPC, or use of diagnostic commands in the
System Controls screen.
Figure 3-44.
NPC Plug-in
1. Includes situations where the slot configuration does not support the plug-in, or the plug-in requires a later/different version of
system software.
2. Indicates a data-affecting hardware failure.
There is no operational need to revert to NCC for bus clocking. If the clock is with
the NPC, and the NPC clock subsequently fails, bus clocking will switch to the
NCC.