PM5362TUPP-PLUS
DATA SHEET
PMC-951010
ISSUE 6
SONET/SDH TRIBUTARY UNIT PAYLOAD PROCESSOR / PERFORMANCE MONITOR
provisioned value. Path signal label unstable, path signal label mismatch and
change of path signal label event are identified.
8.4.1 Clock Generator
The clock generator derives various clocks from the 19.44 MHz system clock and
distributes them to other blocks within the tributary payload processor. The
overall design is totally synchronous, with processing occurring at a 6.48 MHz
rate in each tributary path overhead processor.
8.4.2 Timing Generator
The timing generator identifies the incoming tributary being processed at any
given point in time. Based on the configuration of the RTOP (it can process
various mixes of tributary types), the incoming timing generator extracts the STS-
1 SPE, VC3, or a single TUG3 from a VC4, and identifies the bytes within these
envelopes that correspond to various types of overhead and those that carry
specific tributaries to be processed. The identification of specific tributaries
allows the error monitor and extract blocks to be time-sliced across the mix of
tributaries present in the incoming data stream.
8.4.3 Error Monitor
The error monitor block is a time-sliced state machine. It relies on the timing
generator block to identify the tributary being processed. The error monitor block
contains a set of 12-bit counters that are used to accumulate tributary path BIP-2
errors, and a set of 11-bit counters to accumulate far end block errors (FEBE).
The contents of the counters may be transferred to a holding RAM, and the
counters reset under microprocessor control.
Tributary path BIP-2 errors are detected by comparing the tributary path BIP-2
bits in the V5 byte extracted from the current multiframe, to the BIP-2 value
computed for the previous multiframe. BIP-2 errors may be accumulated on a
block or nibble basis as controlled by software configurable registers. Far end
block errors (FEBEs) are detected by extracting the FEBE bit from the tributary
path overhead byte (V5).
Tributary path remote defect indication (RDI) and remote failure indication (RFI)
are detected by extracting bit 8 and bit 4 respectively of the tributary path
overhead byte (V5). The RDI is recognized when bit 8 of the V5 byte is set high
for five or ten consecutive multiframes while RFI is recognized when bit 4 of V5 is
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52
PMC [ PMC-SIERRA, INC ]
