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2 Transport aspects
11.4.1.1 Status parameters
11.4.1.1.1 Net data rate (NDR)
The status parameter net data rate (NDR) is defined in Table 9-21 as
NDR = DPR – 1 000 kbit/s,
where the DPR represents the DTU payload rate (defined in Table 9-21) and the 1 000 kbit/s is a reference
value for the eoc overhead channel rate that shall be used for the purpose of this calculation.
The NDR shall be calculated by the receiver during initialization and updated during the L0 link state upon
OLR, FRA and RPA using equations for DPR presented in Table 9-21, with BD and BDR values as applicable in
the NOI. It shall not be updated during L2.1N, L2.1B, L2.2, and L3 link states.
The valid values for NDR are all integers from 0 to the configured value of NDR_max (see clause 11.4.2.2).
The NDR shall be represented as a 32-bit unsigned integer expressing the value of NDR in kbit/s. This data
format supports a granularity of 1 kbit/s.
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A special value 2 -1 indicates that NDR is undetermined. All other values are reserved by ITU-T.
The DPU derives the DPU-MIB net data rate reporting parameter NDR from NDR. During the L0 link state,
downstream and upstream actual NDR values are reported in the DPU-MIB. During the L2.1N, L2.1B or L2.2
link state, downstream and upstream net data rate values of the last update in the L0 link state are
available in the DPU-MIB. During the L3 link state (see Figure 12-1), the values of the last update are
available in the DPU-MIB, until the FTU-O transitions to the O-INIT/HS state, at which time the values may
become "undetermined".
11.4.1.1.2 Attainable net data rate (ATTNDR)
The status parameter attainable net data rate (ATTNDR) is defined as the NDR that would be achieved if
control parameter NDR_max were configured at the maximum valid value of NDR_max
(see clause 11.4.2.2), while other control parameters remain at the same value.
The ATTNDR shall be calculated by the receiver during initialization and updated during the L0 link state
upon OLR, FRA and RPA. It shall not be updated during the L2.1N, L2.1B, L2.2, and L3 link states. The
downstream ATTNDR is communicated from the FTU-R to the FTU-O through the eoc.
The valid values for ATTNDR are all integers from 0 to the maximum valid value of NDR_max (see clause
11.4.2.2).
The ATTNDR shall be represented as a 32-bit unsigned integer expressing the value of ATTNDR in kbit/s.
This data format supports a granularity of 1 kbit/s.
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A special value 2 -1 indicates that the parameter is undetermined. All other values are reserved by ITU-T.
The DPU derives the DPU-MIB attainable net data rate reporting parameter ATTNDR from ATTNDR. While
the link is in the L0 state, downstream and upstream ATTNDR values are reported in the DPU-MIB. During
the L2.1N, L2.1B, or L2.2 link state, downstream and upstream attainable net data rate values of the last
update in the L0 link state are available in the DPU-MIB. During the L3 link state (see Figure 12-1), the
values of the last update are available in the DPU-MIB, until the FTU-O transitions to the O-INIT/HS state, at
which time the values may become "undetermined".
11.4.1.1.3 Expected throughput (ETR)
The status parameter expected throughput (ETR) is defined in Table 9-21 as:
ETR 1( RTxOH ) NDR
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