3Com CoreBuilder 9000, Руководство пользователя

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Physical Layer Statistics 207
SONET path alarm indication signal state (Path AIS)
SONET line alarm indication signal state (Line AIS) The AIS is an all-ONES characteristic or adapted information
signal. It is generated to replace the normal traffic signal
when it contains a defect condition in order to prevent
consequential downstream failures being declared or alarms
being raised.
AIS can also be identified as:
- AIS-L (Line Alarm Indication Signal)
- SP-AIS (STS Path Alarm Indication Signal)
- VP-AIS (VT Path Alarm Indication Signal)
SONET line remote defect indication state (Line RDI)
SONET path remote defect indication state (Path RDI) A signal returned to the transmitting Terminating Equipment
upon detecting a Loss of Signal, Loss of Frame, or AIS defect.
RDI was previously known as FERF.
RDI can also be identified as:
- RDI-L (Line Remote Defect Indication)
- RDI-P (STS Path Remote Defect Indication)
- RDI-V (VT Path Remote Defect Indication)
Table 27 Physical Layer Statistics (continued)
Statistic Description