Spirent SmartBits System, Справочное руководство

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Chapter 11: ATM Cards
ATM Alarms
SmartBits System Reference 153
•
LOS . Loss of signal detected.
– For AT-9034B: A LOS is declared if 175
±
75 zero bits are received from the line
before decoding.
– For AT-9045B: A LOS is declared if 160
±
32 zero bits are received from the line
before decoding.
•
Yellow . For AT-9034B PLCP framing mode only. This alarm is declared if the A-bit is
high in an E3 G.751 frame.
•
PLCP OOF . For AT-9045B DS3 PLCP or AT-9034B E3 G.751 mapping modes only.
Physical Layer Convergence Protocol out of frame error condition detected. On the
AT-9045B, PLCP OOF includes LOCD while in PLCP mapping mode.
•
PLCP LOF . For AT-9045B DS3 PLCP or AT-9034B E3 PLCP framing modes only.
PLCP loss of frame error condition detected. LOF is set when PLCP OOF is active for
eight consecutive PLCP frames.
•
PLCP Yellow . For AT-9045B DS3 PLCP or AT-9034B E3 PLCP framing modes only.
PLCP yellow error condition detected. This bit is set when the yellow alarm bit in the
G1 octet of the PLCP frame has been active for ten consecutive PLCP frames.
ATM Alarms, AT-9015 and AT-9020 SmartCards
In SmartWindow, select the Alarms tab from the Statistics window to display the
following alarm conditions for the test.
•
LOCD . For DS1 and E1 direct framing modes. Loss of cell delineation. This alarm is
set when seven consecutive HEC errors are received.
•
OOF . Out of frame condition detected by the DS1 or E1 framer.
•
LOS . Loss of signal detected. In DS1, a LOS is declared when 192 zeroes are
received before decoding. In E1, an LOS is declared when 255 consecutive zeroes are
received before decoding.
•
RAI . Remote alarm indication received in the frame. This is also called a yellow
alarm.
Use only the ESF mode for DS1 framing, per the ATM Forum: This bit is set when 16
consecutive patterns of 00FF appear in the facilities data link.
For E1 framing mode: This bit is set when bit 3 of non-align frames is set to one for
three consecutive occasions.
•
AIS . Alarm indication signal detected in the frame. In DS1 mode, this bit is set when
5 or less zeros are received over a 3 mS window. In E1 mode, this bit is set when less
than three zeros are received in 512 bits.
•
B8ZS . For AT-9015 DS1 only. The absence of B8ZS encoding is detected in the frame
signal.
•
EZA . Excess zeros alarm. Use only the B8ZS coding mode for DS1, per the ATM
Forum: This bit is set when a string of eight or more consecutive zeros are received.