PM5362TUPP-PLUS
DATA SHEET
PMC-951010
ISSUE 6
SONET/SDH TRIBUTARY UNIT PAYLOAD PROCESSOR / PERFORMANCE MONITOR
4. "consecutive event counters" are reset to zero on a change of state.
The pointer interpreter block detects loss of pointer (LOP) in the incoming
tributaries. LOP is declared on entry to the LOP_state as a result of eight
consecutive invalid pointers or eight consecutive NDF enabled indications. LOP
is removed when the same valid pointer with normal NDF is detected for three
consecutive frames. Incoming tributary path AIS (pointer bytes set to all ones)
does not cause entry into the LOP state.
The pointer interpreter block also detects tributary path AIS in the incoming
tributaries. PAIS is declared on entry to the AIS_state after three consecutive
AIS indications. PAIS is removed when the same valid pointer with normal NDF
is detected for three consecutive frames or when a valid pointer with NDF
enabled is detected.
8.3.5 Payload Buffer
The payload buffer is a bank FIFO buffers. It is synchronous in operation and is
based on a time-sliced RAM. The three 19.44 MHz clock cycles in each 6.48
MHz period are shared between the read and write operations. The pointer
interpreter writes tributary payload data and the V5 (or TU3 J1) tag into the
payload buffer. A 16 byte FIFO buffer is provided for each of the (up to 28)
tributaries. Address information is also passed through the payload buffer to
allow FIFO fill status to be determined by the pointer generator.
8.3.6 OutgoingTiming Generator
The outgoing timing generator identifies the outgoing tributary byte being
processed. Based on the configuration of the VTPP, 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 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 OTMF input.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
47
PMC [ PMC-SIERRA, INC ]
