PM5362TUPP-PLUS
DATA SHEET
PMC-951010
ISSUE 6
SONET/SDH TRIBUTARY UNIT PAYLOAD PROCESSOR / PERFORMANCE MONITOR
8.5.2 Timing Generator
The timing generator identifies the incoming tributary being processed at any
given point in time. Based on the configuration of the RTTB (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 alarm monitor and extract blocks to be time-sliced across the mix of
tributaries present in the incoming data stream.
8.5.3 Extract
The extract block is a time-sliced state machine. It uses timing information from
the timing generator block to extract the tributary path trace message bytes (J2)
from all the processed tributaries in the incoming stream. Each tributary in the
incoming stream is allocated an individual receive buffer in the buffer block. The
length of the message and, consequently, the depth of the corresponding buffer
are register programmable to be 16 or 64 bytes. Bytes in the message may be
written to the corresponding buffer in a circular fashion or optionally be
synchronized to the framing pattern embedded in the message. For a 16 byte
message, the first byte is identified by a logic one in the most significant bit. For
a 64 byte message, the last two bytes are set to the ASCII characters of
carriage-return (0DH) and linefeed (0AH).
8.5.4 Alarm Monitor
The alarm monitor block is a time-sliced state machine. It relies on the timing
generator block to identify the tributary being processed. The alarm monitor
block accesses an individual capture and expected buffers in the buffer block for
each tributary in the incoming stream. It also monitors the received message for
consistency. When the identical message is received three or five times, as
controlled by the PER5 register bit, the message is accepted. This accepted
message is then compared with the expected message provision in the buffer
block. If the accepted message differs from the expected message, the trail trace
identifier mismatch (TIM) alarm is raised. TIM alarm is negated if the accepted
and expected messages match. An accepted message that contains all-zero
bytes is treated specially. If the expected messages is not also all-zeros, the TIM
alarm is not affected upon accepting of an all-zero message. If the expected
message is all-zeros, accepting an all-zeros message would negate TIM.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
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PMC [ PMC-SIERRA, INC ]
