Data Sheet
June 2002
TMXF28155 Supermapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
423
Agere Systems Inc.
18 SPE Mapper Functional Description
(continued)
Table 557. Signal Degrade Parameters
Note: The threshold written by the control system is one less than the desired number, except for the SPE_SDLSET[3:0]/SDLCLEAR[3:0]
parameter.
18.14.12 Signal Fail BER Algorithm
A signal fail state is reported by bit SPE_SFB3 (
Table 158 on page 140
) and change of state in bit SPE_SFB3D
(
Table 156
) with the interrupt mask bit SPE_SFB3M (
Table 157
). This bit error rate algorithm operates on B3
errors.
Declaring the signal fail state requires the definition of two measurement windows: a monitoring block consisting of
a number of frames, Ns (SPE_SFNSSET[18:0] (
Table 169 on page 150
)), and a measurement interval consisting
of a number of monitoring blocks, B (SPE_SFBSET[15:0] (
Table 169
)). A block is determined to be bad when the
number of bit errors equals or exceeds a threshold, L (SPE_SFLSET[3:0] (v)). Signal fail is declared when the
number of bad monitoring blocks equals or exceeds the threshold, M (SPE_SFMSET[7:0] (
Table 169
)), for the
measurement interval.
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 169
)), and a measurement interval consisting of a num-
ber of monitoring blocks, B (SPE_SFBCLEAR[11:0] (v)). A block is determined to be good when the number of bit
errors is less than a threshold, L (SPE_SFLCLEAR[3:0] (
Table 169
)). Signal fail is cleared when a number of good
monitoring blocks equals or exceeds the threshold, M (SPE_SFMCLEAR[7:0] (v)), for the measurement 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 155 on page 136
), and forced
to the cleared state with bit SPE_SFCLEAR (
Table 155
).
The above algorithm can detect bit error rates from 1 x 10
–3
to 1 x 10
–9
.
Name
Function
SPE_SDNSSET[18:0] (
Table 168 on page 149
)
Signal Degrade Ns Set.
Number of frames in a monitoring
block for SD.
SPE_SDLSET[3:0] (
Table 168
)
Signal Degrade L Set.
Error threshold for determining if a mon-
itoring block is bad.
SPE_SDMSET[7:0] (
Table 168
)
Signal Degrade M Set.
Threshold of the number of bad moni-
toring blocks in an observation interval. If the number of bad
blocks is below this threshold, then SD is cleared.
SPE_SDBSET[15:0] (
Table 168
)
Signal Degrade B Set.
Number of monitoring blocks in a mea-
surement interval.
SPE_SDNSCLEAR[18:0] (
Table 168
)
Signal Degrade Ns Clear.
Number of frames in a monitoring
block for SD.
SPE_SDLCLEAR[3:0] (
Table 168
)
Signal Degrade L Clear.
Error threshold for determining if a
monitoring block is bad.
SPE_SDMCLEAR[7:0] (
Table 168
)
Signal Degrade M Clear.
Threshold of the number of bad mon-
itoring blocks in an observation interval. If the number of bad
blocks is below this threshold, then SD is cleared.
SPE_SDBCLEAR[15:0] (
Table 168
)
Signal Degrade B Clear.
Number of monitoring blocks in a
measurement interval.
SPE_SDSET (
Table 155 on page 136
)
Signal Degrade Set.
Allows the signal degrade algorithm to be
forced into the failed state (active 0 to 1).
SPE_SDCLEAR (
Table 155
)
Signal Degrade Clear.
Allows the signal degrade algorithm to
be forced into the normal state (active 0 to 1).
SPE_SDB3 (
Table 158 on page 140
)
Signal Degrade BER Algorithm State Bit.
SPE_SDB3D (
Table 156 on page 136
)
Signal Degrade BER Algorithm Delta Bit.
SPE_SDB3M (
Table 157 on page 138
)
Signal Degrade BER Algorithm Mask Bit.