
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
Preliminary Data Sheet, Rev. 1
October2000
212
Lucent Technologies Inc.
SPE Mapper Functional Description
(continued)
SPE Mapper Receive Direction Requirements
(continued)
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 113. STS-1 P-REI Interpretation
The SPE mapper provides a counter to accumulate G1-REI errored bit count in SPE_G1ECNT[15:0] (Table 136)
from G1[7:4]. This counter will hold at its maximum value or rollover (depending on the value of microprocessor bit
SMPR_SAT_ROLLOVER (Table 15)) and update upon the performance monitoring interval.
Signal Degrade BER Algorithm
A signal degrade state bit is SPE_SDB3 (Table 124) with a change of state indication reported in delta bit
SPE_SDB3D (Table 122) and the interrupt mask bit is SPE_SDB3M (Table 123). This bit error rate algorithm oper-
ates 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 134)), and a measurement interval consisting of a
number of monitoring blocks, B (SPE_SDBSET[11:0] (Table 134)). A block is determined bad when the number of
bit errors equals or exceeds a threshold, L (SPE_SDLSET[3:0] (Table 134)). Signal degrade is declared when a
number of bad monitoring blocks equals or exceeds the threshold, M (SPE_SDMSET[7:0] (Table 134)), 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 134)), and a measurement interval consisting of a
number of monitoring blocks, B (SPE_SDBCLEAR[11:0] (Table 134)). A block is determined good when the num-
ber of bit errors is less than a threshold, L (SPE_SDLCLEAR[3:0] (Table 134)). Signal degrade is cleared when a
number of good monitoring blocks equals or exceeds the threshold, M (SPE_SDMCLEAR[7:0] (Table 134)), 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 121) and forced to the
cleared state with bit SPE_SDCLEAR (Table 121). The controls are provided to force the BER algorithm 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)