Page 953 - 5G Basics - Core Network Aspects

Transport aspects 2

The fields are defined as follows:

Field 1 "L2 link state control parameter field length", indicates the length of the L2 link state control
parameter field in bytes, excluding the L2 link state control parameter field length field. The length shall be
represented as an unsigned integer.
Field 2 "Downstream target SNR margin for L2.1 and L2.2 (L2_TARSNRM)" indicates the target SNR margin
for data subcarriers of the downstream RMC symbols during L2.1 and L2.2 operation (see clause 13.4.1.3
and clause 13.4.2.3, respectively). The definition, formatting and range of valid values is specified in
clause 13.4.1.5.3.

Field 3 "Downstream maximum SNR margin for L2.1 (L2.1_MAXSNRM)" indicates the maximum SNR margin
for data subcarriers of the downstream RMC symbols during L2.1 operation (see clause 13.4.1.3). The
definition, formatting and range of valid values is specified in clause 13.4.1.5.4.

Field 4 "Downstream maximum NDR in L2.1 (L2.1_NDR_max)" indicates the maximum NDR in the L2.1 link
state in downstream. The definition, formatting and range of valid values is specified in clause 13.4.1.5.2.

Field 5 "Downstream minimum ETR in L2.1 (L2.1_ETR_min)" indicates the minimum ETR in the L2.1 link
state in downstream. The definition, formatting and range of valid values is specified in clause 13.4.1.5.1.

Field 6 "Downstream minimum ETR at L2.1 exit (L2.1_Exit_ETR_min)" indicates the minimum ETR after the
exit out of the L2.1 link state in downstream. The definition, formatting and range of valid values is
specified in clause 13.4.1.5.6.

Field 7 "Downstream and upstream maximum NDR in L2.2 (L2.2_NDR_max)" indicates the maximum NDR
in the L2.2 link state for both directions. The definition, formatting and range of valid values is specified in
clause 13.4.2.5.2.
Field 8 "Downstream and upstream minimum ETR in L2.2 (L2.2_ETR_MIN)" indicates the minimum ETR in
the L2.2 link state for both directions. The definition, formatting and range of valid values is specified in
clause 13.4.2.5.1.
Field 9 "Downstream Rate adaptation downshift SNR margin in L2.1 (L2.1_RA_DSNRMds)": The definition,
formatting and range of valid values is specified in clause 13.4.1.5.7.
Field 10 "Downstream Rate adaptation upshift SNR margin in L2.1 (L2.1_RA_USNRMds)": The definition,
formatting and range of valid values is specified in clause 13.4.1.5.7.
Field 24 "PMD capabilities" indicates the PMD capabilities of the FTU-O as shown in Table 12-41.2.

Table 12-41.2 – PMD capabilities of the FTU-O

Field name Format Description

FTU-O maximum bit One byte: [000000aa] Indicates the maximum bit loading supported by the FTU-O
loading transmitter:
• aa = 00 – maximum bit loading = 12 bits
• aa = 01 – maximum bit loading = 13 bits
• aa = 10 – maximum bit loading = 14 bits
• aa = 11 – Reserved by ITU-T

Field 25 ''CD_time_out_1 during fast retrain'' indicates the timeout for the transmission of O-P-CHANNEL-
DISCOVERY 1-1 in case of a fast retrain. The value shall be encoded as one byte with valid values from 1 to
40 representing the timeout in steps of 1 second. The value shall be less than or equal to the
CD_time_out_1 value negotiated during the last ITU-T G.994.1 session. The FTU-R shall support all valid
values if it indicated support for ''CD time_out'' during the last ITU-T G.994.1 session.
Field 26 ''CD_time_out_2 during fast retrain'' indicates the timeout for the initialization after the beginning
of O-P-CHANNEL-DISCOVERY 1-1 in case of a fast retrain. The value shall be encoded as one byte with valid
values from 1 to 80 representing the timeout in steps of 1 second. The value shall be less than or equal to

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