Page 1156 - 5G Basics - Core Network Aspects

2 Transport aspects

During an IAE condition the code "1011" is inserted into the BEI/BIAE field and the error count is ignored.
Otherwise the error count (0-8) is inserted into the BEI/BIAE field. The remaining six possible values
represented by these four bits can only result from some unrelated condition and shall be interpreted as
zero errors (see Table 15-4) and BIAE not active.

The ODUk contains one instance of ODU TCM BEI/BIAE overhead. The ODUCn contains n instances of the
ODU TCMi BEI/BIAE overhead, numbered 1 to n (BEI/BIAE #1 to BEI/BIAE #n).

Table 15-6  ODU TCM BEI/BIAE interpretation

ODUk TCM BEI/BIAE
BIAE BIP violations
bits 1 2 3 4
0 0 0 0 false 0
0 0 0 1 false 1
0 0 1 0 false 2
0 0 1 1 false 3
0 1 0 0 false 4
0 1 0 1 false 5
0 1 1 0 false 6
0 1 1 1 false 7
1 0 0 0 false 8

1 0 0 1, 1 0 1 0 false 0
1 0 1 1 true 0
1 1 0 0 to 1 1 1 1 false 0

15.8.2.2.5 ODU TCM status (STAT)

For each tandem connection monitoring field, three bits are defined as status bits (STAT). They indicate the
presence of a maintenance signal, if there is an incoming alignment error at the source TC-CMEP, or if there
is no source TC-CMEP active (see Table 15-7).
The ODUk and ODUCn contain one instance of ODU TCM STAT overhead.

Table 15-7  ODU TCM status interpretation

TCM byte 3
Status
bits 6 7 8

0 0 0 No source TC
0 0 1 In use without IAE
0 1 0 In use with IAE
0 1 1 Reserved for future international standardization
1 0 0 Reserved for future international standardization
1 0 1 Maintenance signal: ODU-LCK
ODUk: Maintenance signal: ODUk-OCI
1 1 0
ODUCn: Reserved for future international standardization
1 1 1 Maintenance signal: ODU-AIS

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