Appendix
F Alarm Forwarding
Installation and Operation Manual
F-6
3BTDM-to-PSN Alarm Forwarding
ACE-3105, ACE-3205 Ver. 5.2
F.3
TDM-to-PSN Alarm Forwarding
The TDM over PSN alarm forwarding mechanism is based on the L, R and M bits of
the CESoPSN/SAToP Control Word (for more information, refer to
Appendix E
).
The TDM alarm forwarding mechanism consist of handling:
•
TDM error states
•
PSN error states
•
TDM RAI states.
Accordingly, the TDM channel enters an alarm forwarding state on the local ACE
unit if one of the following occurs:
•
In Structure-agnostic (unstructured) mode – when LOS is detected on the
TDM interface
•
In Structure-aware (structured) mode – when LOS, OOF or AIS is detected on
the TDM interface
•
A TDM PW failure ('forward-detect state') – due to persistent packet loss or
buffer underrun.
Forwarding in Structure-Agnostic Mode
In structure-agnostic (unstructured) mode, alarms are forwarded depending on
the TDM failure type:
•
TDM line failure (see
) – causes the TDM PW to enter a 'forward-
detect-state' and use the L and M bits (L=1, M=0) of the SAToP control word
to propagate the alarm towards the remote ACE unit. Then, upon receiving
the L and M bit values, the remote ACE unit generates AIS signals towards the
remote TDM end.
Figure
F-16. TDM Line Failure in Structure-Agnostic Mode
•
TDM PW failure (see
) – causes the local ACE to send an AIS signal
towards the TDM end, and to propagate the alarm in the upstream direction
over the PSN using the R bit (R=1) of the SAToP control word.
