Page 1166 - 5G Basics - Core Network Aspects

2 Transport aspects

16.5.1 ODU alarm indication signal (ODU-AIS)

ODUk-AIS is specified as all "1"s in the entire ODU signal, excluding the frame alignment overhead (FA OH),
OTU overhead (OTU OH) (see Figure 16-3).
The ODUk contains one instance of ODU AIS. The ODUCn contains n instances of ODU AIS, numbered 1 to n
(ODU AIS #1 to #n).

Figure 16-3  ODU-AIS

In addition, the ODU-AIS signal may be extended with one or more levels of ODU tandem connection,
GCC1, GCC2, EXP and/or APS/PCC overhead before it is presented at the OTN interface. This is dependent
on the functionality between the ODU-AIS insertion point and the OTN interface.
The presence of the ODU-AIS is detected by monitoring the ODU STAT bits in the PM and TCMi overhead
fields.
16.5.2 ODUk open connection indication (ODUk-OCI)

ODUk-OCI is specified as a repeating "0110 0110" pattern in the entire ODUk signal, excluding the frame
alignment overhead (FA OH) and OTUk overhead (OTUk OH) (see Figure 16-4).

NOTE – ODUCn OCI is not defined.

Figure 16-4  ODUk-OCI

NOTE – The repeating "0110 0110" pattern is the default pattern; other patterns are also allowed as long as the STAT
bits in the PM and TCMi overhead fields are set to "110".

In addition, the ODUk-OCI signal may be extended with one or more levels of ODUk tandem connection,
GCC1, GCC2, EXP and/or APS/PCC overhead before it is presented at the OTM interface. This is dependent
on the functionality between the ODUk-OCI insertion point and the OTM interface.
The presence of ODUk-OCI is detected by monitoring the ODUk STAT bits in the PM and TCMi overhead
fields.

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