PM5361TUPP
DATA SHEET
PMC-920526
ISSUE 8
TRIBUTARY UNIT PAYLOAD PROCESSOR
9.3.6 OutgoingTiming Generator
The outgoing timing generator identifies the outgoing tributary byte being
processed. Based on the configuration of the TPP , the outgoing timing
generator effectively constructs the STS-1 SPE, VC3, or VC4, and identifies the
bytes within these envelopes that correspond to various types of overhead and
bytes that carry specific tributaries. The identification of specific tributaries allows
the pointer generator to be time-sliced across the mix of tributaries to be sourced
in the outgoing data stream. The identification of the V1-V3 bytes of VTs, or TUs
(H1-H3 bytes of TU3s) allows the pointer generator to function.
The sequence H4 bytes is generated by each tributary payload processor and
inserted into the outgoing administrative units. The six most significant bits of H4
are set to logic 1. The sequence of the remaining two H4 bits is determined by
the OTMF input when enabled or from the incoming multiframe alignment.
9.3.7 Pointer Generator
The pointer generator is a time-sliced state machine that can process up to 28
independent tributaries. The state vector is saved in RAM at the address
associated with the current tributary. The pointer generator fills the outgoing
tributary synchronous payload envelopes with bytes read from the associated
FIFO in the payload buffer for the current tributary. The pointer generator creates
pointers in the V1-V3 bytes (or H1-H3 bytes in the case of TU3s) of the outgoing
data stream. The marker that tags the V5 byte (or J1 byte in the case of a TU3)
that is passed through the payload buffer is used to align the pointer. The
outgoing timing generator directs the pointer generator to the FIFO is the
payload buffer associated with the tributary being processed. The pointer
generator monitors the fill levels of the payload buffers and inserts outgoing
pointer justifications as necessary to avoid FIFO spillage. Normally, the pointer
generator has a FIFO dead band of 4 bytes. The dead band can be collapse to
one so that any incoming pointer justifications will be reflected by a
corresponding outgoing justification with no attenuation. Signals are output by
the pointer generator that identify outgoing V5 bytes (or J1 bytes in the case of a
TU3) and the tributary synchronous payload envelopes. These facilitate tributary
performance monitoring external to the TUPP. On a per tributary basis, tributary
path AIS and tributary idle (unequipped) can be inserted as controlled by
microprocessor accessible registers. The idle code is selectable globally for the
entire VC3 or TUG3 to be all zeros or all ones. It is also possible to force an
inverted new data flag on individual tributaries for the purpose of diagnosing
downstream pointer processors. Tributary path AIS is automatically inserted into
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