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IXF6048
—
51/155/622/2488 Mbit/s SONET/SDH Cell/Packet Interface
118
Datasheet
An
Excessive Error Defect (EED)
indication (see register IS_MUX) is generated by integrating
the B2 errors in a sliding window. Integration is also used when clearing the EED indication. Six
registers allow the configuration of EED indication thresholds, hysteresis, and probability of
detection. They are WINSZ_SB2, CWIN_SB2, E#_EXCWIN_SB2, WINSZ_CB2, CWIN_CB2,
and E#_NEXCWIN_CB2. These six registers allow configuring the EED thresholds (BER setting
and clearing thresholds are fully independent) from a Bit Error Rate of 10
–
3 to a bit error rate of
10
–
8, even in the case of a non-Gaussian statistical distribution of errors. An active EED indication
can be configured to insert an AIS signal, to generate Signal Fault defect, and/or to generate an
RDI defect (see register R_MST_C, bit #7 and #2).
A
Degraded Signal Defect (DSD)
indication (see register IS_MUX) is also generated by
integrating the B2 errors in a different sliding window. Integration is also used when clearing the
DSD indication. Six registers allow the configuration of DSD indication thresholds, hysteresis, and
probability of detection. They are WINSZ_SDEGB2, CWIN_SDEGB2, E#_DEGWIN,
WINSZ_CDEGB2, CWIN_CDEGB2, and E#_NDEGWIN_CB2. These six registers allow
configuring the DSD thresholds (BER setting and clearing thresholds are fully independent) from a
Bit Error Rate of 10
–
3 to a bit error rate of 10
–
11, even in the case of a non-Gaussian statistical
distribution of errors (including bursty distribution of errors).
Based on B2 detected errors per frame, an
MS-REI
value is encoded (as BIP or Block errors: see
configuration register R_MST_C). This value is internally looped to the transmitter and provided
serially at the Receive Section Alarm bus output, RSAL.
4.4.1.4.2
K1 and K2 Bytes: Automatic Protection Switching Channel
These bytes are assigned for the APS signaling. A change in K1 byte for three consecutive frames
is indicated in register IS_MUX (RcvK1Chg bit) and allows the updating of register R_K2K1 (8
LSB bits). A change in K2 byte for three consecutive frames is indicated in register IS_MUXH
(RcvK2Chg bit) and allows the updating of register R_K2K1 (8 MSB bits). Register R_K2K1
provides so microprocessor access to both K1 and K2 received filtered values. When the value of
K1 byte has not been detected identical for 3 consecutive frames in a window of 16 frames, a
RcvK1Unstable alarm is indicated in register IS_MUX. When the value of K2 byte has not been
detected identical for 3 consecutive frames in a window of 16 frames, a RcvK2Unstable alarm is
indicated in register IS_MUX.
It is possible to configure the K1/K2 process as for a single channel (see configuration register
R_MST_C). In this mode, a change in K1/K2 bytes for three consecutive frames is indicated in
register IS_MUX and allows the updating of register R_K2K1, providing K1/K2 received APS
filtered value.
The K1 and K2 received filtered values (APS channel), the indications of K1 and K2 change, and
the K1 and K2 Unstable alarms are provided serially at the Receive Section Alarm bus output,
RSAL.
The K1 and K2 receive bytes are provided serially at RSOH serial bus output.
4.4.1.4.3
MS-RDI Via K2 Byte (Generation and Detection)
The Multiplex Section Remote Defect Indication (MS-RDI) is used to tell the transmit end that the
received end has detected an incoming section defect or is receiving MS-AIS. The MS-RDI
generated defect is internally looped to the transmitter and provided serially at the Receive Section
Alarm bus output, RSAL.