S/UNI®-8x155 ASSP Telecom Standard Product Data Sheet
Released
NDF_enable
3 x AIS_ind
8 x inv_point
8 x NDF_enable
Notes
single NDF_enable indication
three consecutive AIS indications
eight consecutive inv_point indications
eight consecutive NDF_enable indications
1. The transitions from NORM_state to NORM_state do not represent state changes but imply offset
changes.
2. 3 x new_point takes precedence over other events and if the IINVCNT bit is set resets the inv_point
count.
3. All three offset values received in 3 x eq_new_point must be identical.
4. "Consecutive event counters" are reset to zero on a change of state except for consecutive NDF
count.
The Pointer Interpreter detects loss of pointer (LOP) in the incoming STS-3c/STM-1 stream.
LOP is declared on entry to the LOP_state as a result of eight consecutive invalid pointers or
eight consecutive NDF enabled indications. The alarm condition is reported in the receive
alarm port and is optionally returned to the source node by signaling the corresponding Transmit
Path Overhead Processor in the local S/UNI-8x155 to insert a path RDI indication.
The Pointer Interpreter detects path AIS in the incoming STS-3c/STM-1 stream. PAIS is
declared on entry to the AIS_state after three consecutive AIS indications. The alarm condition
reported in the receive alarm port and is optionally returned to the source node by signaling the
corresponding Transmit Path Overhead Processor in the local SONET/SDH equipment to insert
a path RDI indication.
Invalid pointer indications (inv_point), invalid NDF codes, new pointer indications
(new_point), discontinuous change of pointer alignment, and illegal pointer changes are also
detected and reported by the Pointer Interpreter block via register bits. An invalid NDF code is
any NDF code that does not match the NDF enabled or NDF disabled definitions. The third
occurrence of equal new_point indications (3 x eq_new_point) is reported as a discontinuous
change of pointer alignment event (DISCOPA) instead of a new pointer event and the active
offset is updated with the receive pointer value. An illegal pointer change is defined as a
inc_ind or dec_ind indication that occurs within three frames of the previous inc_ind, dec_ind
or NDF_enable indications. Illegal pointer changes may be optionally disabled via register bits.
The active offset value is used to extract the path overhead from the incoming stream and can be
read from an internal register.
10.5.2 SPE Timing
The SPE Timing Block provides SPE timing information to the Error Monitor and the Extract
blocks. The block contains a free running timeslot counter that is initialized by a J1 byte
identifier (which identifies the first byte of the SPE). Control signals are provided to the Error
Monitor and the Extract blocks to identify the Path Overhead bytes and to downstream circuitry
to extract the ATM cell or POS payload.
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC- 2010299, Issue 2
74
PMC [ PMC-SIERRA, INC ]
