PM5366-PI PMC-Sierra, Inc., PM5366-PI Datasheet - Page 92

• Manufacturer Part Number: PM5366-PI
• Description: HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER AND M13 MULTIPLEXER
• Manufacturer: PMC-Sierra, Inc.

PRELIMINARY
DATASHEET
PMC-2010672
PROPRIETARY AND CONFIDENTIAL
While the DS3-FRMR is synchronized to the DS3 M-frame, the F-bit and M-bit
positions in the DS3 stream are examined. An out-of-frame defect is detected
when 3 F-bit errors out of 8 or 16 consecutive F-bits are observed (as selected
by the M3O8 bit in the DS3 FRMR Configuration Register), or when one or more
M-bit errors are detected in 3 out of 4 consecutive M-frames. The M-bit error
criteria for OOF can be disabled by the MBDIS bit in the DS3 Framer
Configuration register. The 3 out of 8 consecutive F-bits out-of-frame ratio
provides more robust operation, in the presence of a high bit error rate, than the
3 out of 16 consecutive F-bits ratio. Either out-of-frame criteria allows an out-of-
frame defect to be detected quickly when the M-subframe alignment patterns or,
optionally, when the M-frame alignment pattern is lost.
Also while in-frame, line code violations, M-bit or F-bit framing bit errors, and P-
bit parity errors are indicated. When C-bit parity mode is enabled, both C-bit
parity errors and far end block errors are indicated. These error indications, as
well as the line code violation and excessive zeros indication, are accumulated
over 1 second intervals with the Performance Monitor (DS3-PMON). Note that
the framer is an off-line framer, indicating both OOF and COFA events. Even if
an OOF is indicated, the framer will continue indicating performance monitoring
information based on the previous frame alignment.
Three DS3 maintenance signals (a RED alarm condition, the alarm indication
signal, and the idle signal) are detected by the DS3-FRMR. The maintenance
detection algorithm employs a simple integrator with a 1:1 slope that is based on
the occurrence of "valid" M-frame intervals. For the RED alarm, an M-frame is
said to be a "valid" interval if it contains a RED defect, defined as an occurrence
of an OOF or LOS event during that M-frame. For AIS and IDLE, an M-frame
interval is "valid" if it contains AIS or IDLE, defined as the occurrence of less than
15 discrepancies in the expected signal pattern (1010... for AIS, 1100... for IDLE)
while valid frame alignment is maintained. This discrepancy threshold ensures
the detection algorithms operate in the presence of a 10
the expected pattern may be selected to be: the framed "1010" signal; the
framed arbitrary DS3 signal and the C-bits all zero; the framed "1010" signal and
the C-bits all zero; the framed all-ones signal (with overhead bits ignored); or the
unframed all-ones signal (with overhead bits equal to ones). Each "valid" M-
frame causes an associated integration counter to increment; "invalid" M-frames
cause a decrement. With the "slow" detection option, RED, AIS, or IDLE are
declared when the respective counter saturates at 127, which results in a
detection time of 13.5 ms. With the "fast" detection option, RED, AIS, or IDLE
are declared when the respective counter saturates at 21, which results in a
detection time of 2.23 ms (i.e., 1.5 times the maximum average reframe time).
RED, AIS, or IDLE are removed when the respective counter decrements to 0.
DS3 Loss of Frame detection is provided as recommended by ITU-T G.783 with
programmable integration periods of 1ms, 2ms, or 3ms. While integrating up to
ISSUE 1
80
HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER
-3
bit error rate. For AIS,
AND M13 MULTIPLEXER
PM5366 TEMAP-84