PMC-Sierra, Inc.
PM5356
S/UNI-622-MAX
DATASHEET
S/UNI-622-MAX
PMC-1980589
ISSUE 5
SATURN USER NETWORK INTERFACE (622-MAX)
frames containing identical K1 bytes. The detection of invalid APS codes is done in software by
polling the RASE APS K1 Register and the RASE APS K2 Register.
Bit Error Rate Monitor
The Bit Error Monitor Block (BERM) calculates the received line BIP-96 error detection code (B2)
based on the line overhead and synchronous payload envelope of the receive data stream. The
line BIP-96 code is a bit interleaved parity calculation using even parity. Details are provided in
the references. The calculated BIP code is compared with the BIP-96 code extracted from the B2
bytes of the following frame. Any differences indicate that a line layer bit error has occurred. Up
to 768,000 (96 BIP/frame x 8000 frames/second) bit errors can be detected per second for STS-
12c/STM-4-4c rate.
The BERM accumulates these line layer bit errors in a 20 bit saturating counter that can be read
via the microprocessor interface. During a read, the counter value is latched and the counter is
reset to 0 (or 1, if there is an outstanding event). Note, this counter should be polled at least once
per second to avoid saturation that in turn may result in missed bit error events.
The BERM block is able to simultaneously monitor for signal fail (SF) or signal degrade (SD)
threshold crossing and provide alarms through software interrupts. The bit error rates associated
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with the SF or SD alarms are programmable over a range of 10 to 10 . Details are provided in
the Operations section.
Synchronization Status Extraction
The Synchronization Status Extraction (SSE) Block extracts the synchronization status (S1) byte
from the line overhead. The SSE block can be configured to capture the S1 nibble after three or
after eight frames with the same value (filtering turned on) or after any change in the value
(filtering turned off). The S1 nibble can be read via the CBI interface.
10.5 Receive Path Overhead Processor (RPOP)
The Receive Path Overhead Processor (RPOP) provides pointer interpretation, extraction of path
overhead, extraction of the synchronous payload envelope, and path level alarm indication and
performance monitoring.
Pointer Interpreter
The Pointer Interpreter interprets the incoming pointer (H1, H2) as specified in the references.
The pointer value is used to determine the location of the path overhead (the J1 byte) in the
incoming STS-12c/STM-4-4c stream. The algorithm can be modeled by a finite state machine.
Within the pointer interpretation algorithm three states are defined as shown below:
NORM_state (NORM)
AIS_state (AIS)
LOP_state (LOP)
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