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2                                                 Transport aspects


                                   Table 9-5 – Downstream RMC command (sent by FTU-O only)

                     Field name              Format                           Description
             Upstream logical frame     Three bytes        Request for upstream logical frame configuration
             configuration request                         parameters (see clause 8.1.1 for the definition of its
                                                           implementation). (Note 2)
                                                           The format of Upstream logical frame configuration request
                                                           is defined in Table 9-7.
             Expected transmission time   One byte: [000   aaaaa = expected transmission time expressed in symbols
             (ETT)                      aaaaa]             for the current logical frame, specified as the symbol
                                                           position index of the last data symbol expected to be
                                                           transmitted in the logical frame. The actual transmission
                                                           time shall be less than or equal to the value communicated
                                                           (Note 3).

             DTU sync value (NB)        Two bytes:         The value of NB, for the current logical frame (see definition
                                        byte 0 [s7 ... s0]   of NB in clause 9.5) expressed in bytes:
                                        byte  1 [0000 s11...   The value is coded as a 12 bits unsigned integer [s11 ... s0]
                                        s8]                with s0 the LSB.
                                                           The valid range for the DTU sync value is from 00016 to
                                                           FEF16.
             Current active bit-loading   One byte: [bbbb   Indication for the active bit-loading table to be used in the
             table identifier           aaaa]              current logical frame, expressed as a value of FCCC
                                                           (see clause 13.3.1.1.3).
                                                           aaaa = Identifier for the active bit-loading table to be used
                                                           over the NOI.
                                                           bbbb = Identifier for the active bit-loading table to be used
                                                           over the DOI (Note 1). See Table 9-10.

             NOTE 1 – If only the NOI is used (i.e., if TTR ds ≥ TBUDGET ds) for a given logical frame, the identifier corresponding to the DOI shall
             be set to 0000 by the transmitter and ignored by the receiver.
             NOTE 2 – If the FTU-R receives a new upstream logical frame configuration request in the downstream RMC of downstream
             logical frame with CNT LF,ds = N + M SF, the FTU-R shall indicate this new configuration in the RMC starting from upstream logical
             frame with CNT LF,us = N+1 and apply this new configuration in the logical frame with CNT LF,us = N+1 if MB equals to 0 or with
             CNT LF,us = N + 2 if MB equals to 1 (see Figure 10-27).
             NOTE 3 – If RMC is the only symbol expected to be transmitted in a logical frame, the value of ETT shall be set to 00000 2.




































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