
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
Preliminary Data Sheet, Rev. 1
October2000
214
Lucent Technologies Inc.
SPE Mapper Functional Description
(continued)
SPE Mapper Receive Direction Requirements
(continued)
Clearing the signal fail state requires the definition of two measurement windows. A monitoring block consisting of
a number of frames, Ns (SPE_SFNSCLEAR[18:0] (Table 135)), and a measurement interval consisting of a num-
ber of monitoring blocks, B (SPE_SFBCLEAR[11:0] (Table 135)). A block is determined good when the number of
bit errors is less than a threshold, L (SPE_SFLCLEAR[3:0] (Table 135)). Signal fail is cleared when a number of
good monitoring blocks equals or exceeds the threshold, M (SPE_SFMCLEAR[7:0] (Table 135)), for the measure-
ment interval.
The set parameters are used when the signal fail state is clear, and the clear parameters are used when the signal
fail state is declared.
The signal fail state may be forced to the declared state with bit SPE_SFSET (Table 121) and forced to the cleared
state with bit SPE_SFCLEAR (Table 121).
The above algorithm can detect bit error rates from 1 x 10
–3
to 1 x 10
–9
.
Table 115. Signal Fail Parameters
Note:
The thresholds written by the control system is one less than the desired number, except for the
SPE_SFLSET[3:0]/SFLCLEAR[3:0] parameter.
Name
Function
SPE_SFNSSET[18:0] (Table 135)
SPE_SFLSET[3:0] (Table 135)
Signal Fail Ns Set.
Number of frames in a monitoring block for SF.
Signal Fail L Set.
Error threshold for determining if a monitoring block is
bad.
Signal Fail M Set.
Threshold of the number of bad monitoring blocks in
an observation interval. If the number of bad blocks is below this thresh-
old, then SF is cleared.
Signal Fail B Set.
Number of monitoring blocks.
Signal Fail Ns Clear.
Number of frames in a monitoring block for SF.
Signal Fail L Clear.
Error threshold for determining if a monitoring block
is bad.
Signal Fail M Clear.
Threshold of the number of bad monitoring blocks in
an observation interval. If the number of bad blocks is below this thresh-
old, then SF is cleared.
Signal Fail B Clear.
Number of monitoring blocks.
Signal Fail Set.
Allows the signal degrade algorithm to be forced into the
failed state (active 0 to 1).
Signal Fail Clear.
Allows the signal degrade algorithm to be forced into
the normal state (active 0 to 1).
Signal Fail BER Algorithm State Bit.
Signal Fail BER Algorithm Delta Bit.
Signal Fail BER Algorithm Mask Bit.
SPE_SFMSET[7:0] (Table 135)
SPE_SFBSET[15:0] (Table 135)
SPE_SFNSCLEAR[18:0] (Table 135)
SPE_SFLCLEAR[3:0] (Table 135)
SPE_SFMCLEAR[7:0] (Table 135)
SPE_SFBCLEAR[15:0] (Table 135)
SPE_SFSET (Table 121)
SPE_SFCLEAR (Table 121)
SPE_SFB3 (Table 124)
SPE_SFB3D (Table 122)
SPE_SFB3M (Table 123)