STANDARD PRODUCT
PM5365 TEMAP
DATASHEET
PMC-1991148
ISSUE 3
HIGH DENSITY VT/TU MAPPER
AND M13 MULTIPLEXER
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 allows the pointer generator to function.
The sequence of 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 multiframe alignment.
9.15.7 Pointer Generator
The pointer generator block generates the tributary pointers (V1/V2) as specified
in the references. The pointer value is used to determine the location of the
tributary path overhead byte (V5) on the outgoing stream.
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 of the outgoing data stream. The marker
that tags the V5 byte that is passed through the payload buffer is used to align
the pointer. The outgoing timing generator directs the pointer generator to the
FIFO in the payload buffer that is 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 two 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 and the tributary
synchronous payload envelopes. 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 outgoing tributaries
if the pointer interpreter detects tributary path AIS on the corresponding incoming
tributary.
Proprietary and Confidential to PMC-Sierra, Inc. and for its Customers’ Internal Use
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PMC [ PMC-SIERRA, INC ]
