TMXF28155/51 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
Preliminary Data Sheet
May 2001
416
Agere Systems Inc.
18 SPE Mapper Functional Description
(continued)
18.14.10 REI-P Detect
Bits 7 through 4 of the G1 byte are allocated for use as a path remote error indication function (REI-P).
I
For STS-1 signals, bits 7 through 4 of the G1 byte are allocated for REI-P which conveys the error count detected
by the PTE (using the path BIP-8 code B3) back to its peer PTE as follows.
Table 544. STS-1 P-REI Interpretation
The SPE mapper provides a counter to accumulate G1-REI errored bit count in SPE_G1ECNT[15:0] (
Table 160 on
page 147
) from G1[7:4]. This counter will hold at its maximum value or roll over (depending on the value of micro-
processor bit SMPR_SAT_ROLLOVER (
Table 67 on page 68
)) and update upon the performance monitoring inter-
val.
18.14.11 Signal Degrade BER Algorithm
A signal degrade state bit is SPE_SDB3 (
Table 148 on page 137
) with a change of state indication reported in delta
bit SPE_SDB3D (
Table 146 on page134
) and the interrupt mask bit is SPE_SDB3M (
Table 147
). This bit error rate
algorithm operates on B3 errors.
Declaring the signal degrade state requires the definition of two measurement windows. A monitoring block con-
sisting of a number of frames, Ns (SPE_SDNSSET[18:0] (
Table 158 on page 146
)), and a measurement interval
consisting of a number of monitoring blocks, B (SPE_SDBSET[11:0] (
Table 158
)). A block is determined bad when
the number of bit errors equals or exceeds a threshold, L (SPE_SDLSET[3:0] (
Table 158
)). Signal degrade is
declared when a number of bad monitoring blocks equals or exceeds the threshold, M (SPE_SDMSET[7:0]
(
Table 158
)), for the measurement interval.
Clearing the signal degrade state requires the definition of two measurement windows. A monitoring block consist-
ing of a number of frames, Ns (SPE_SDNSCLEAR[18:0] (
Table 158
)), and a measurement interval consisting of a
number of monitoring blocks, B (SPE_SDBCLEAR[11:0] (
Table 158
)). A block is determined good when the num-
ber of bit errors is less than a threshold, L (SPE_SDLCLEAR[3:0] (
Table 158
)). Signal degrade is cleared when a
number of good monitoring blocks equals or exceeds the threshold, M (SPE_SDMCLEAR[7:0] (
Table 158
)), for the
measurement interval.
The set parameters are used when the signal degrade state is clear, and the clear parameters are used when the
signal degrade state is declared.
The signal degrade state may be forced to the declared state with bit SPE_SDSET (
Table 145 on page134
) and
forced to the cleared state with bit SPE_SDCLEAR (
Table 145
). The controls are provided to force the BER algo-
rithm into the failed state or normal state, respectively.
The above algorithm can detect bit error rates from 1 x 10
–
3
to 1 x 10
–
9
.
G1[7:4] Code
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
—
1111
Code Interpretation
0 (no errors)
1
2
3
4
5
6
7
8
0 (no errors)