ETH-CSF PDU structure

The ETH-CSF protocol data unit (PDU) structure is detailed below.

The format of the CSF PDU used to support the ETH-CSF function is shown in the following figure.

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CSF PDU format

The fields of the CSF PDU format are described in the following table.

Table 1. CSF PDU format fields
Field Description
MEG Level 3-bit field to carry the local MEG level
Version 0
OpCode PDU type is CSF (52)
Flags 3-bit Type sub-element and a 3-bit Period sub-element

The format of the Flags field is illustrated in the following figure.

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Flags format

The Type field uses bits 6 through 4 to indicate the CSF type, with values as shown in the following table.

Table 2. CSF Type values
Flags [6:4] Type Description
000 LOS Client loss of signal
001 FDI/AIS Client forward defect indication
010 RDI Client reverse defect indication
011 DCI Client defect clear indication

The Period field uses bits 3 through 1 to indicate the transmission period, with values as shown in the following table.

Table 3. CSF Period values
Flags [3:1] Type Description
000 Invalid value Invalid value for CSF PDUs
001 For further study For further study
010 For further study For further study
011 For further study For further study
100 1 second 1 frame per second
101 For further study For further study
110 1 minute 1 frame per minute
111 For further study For further study

TLV Offset is set to 0.

End TLV is an all-zeroes octet value.