PM5363 TUPP+622
TUPP+622
DATASHEET
PMC-1981421
ISSUE 4
SONET/SDH TRIBUTARY UNIT PAYLOAD PROCESSOR FOR 622 MBIT/S
INTERFACES
3.
4.
All three offset values received in 3 x eq_new_point must be identical.
"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.
The pointer interpreter may be bypassed. External logic upstream would identify
tributary payload bytes and tributary payload frame boundaries via the ITPL and
ITV5 signals, respectively. Loss of pointer and tributary path AIS alarm detection
will be disabled. Alarm conditions are conveyed by the IAIS input signal.
10.3.5 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.
10.3.6 Outgoing Timing 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
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96
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