Page 844 - 5G Basics - Core Network Aspects

2 Transport aspects

Table 11-43 – Vectoring feedback responses (transmitted by the FTU-R)

Name Length (bytes) Byte Content

Vectoring feedback 5 + NVFRB 2 8016 (Note 1)
data/ACK
3 Segment code (SC), represented as defined in
clause 11.2.2.3.
4 and 5 Superframe count (CNTSF) represented as
unsigned integer in the range as defined in
clause 10.6 (Note 2).
6 to 5 + N_VFRB Vectoring feedback data, represented with
N_VFRB bytes, as defined in clause 10.3.2.4.1
(Note 3).
NACK 3 2 8116 (Note 1)

3 One byte for reason code (see Table 11-44).
NOTE 1 – All other values for this byte are reserved by ITU-T.
NOTE 2 – This field identifies the downstream sync symbol for which vectoring feedback data is reported.
NOTE 3 – This field shall carry the VFRB using the format described in clause 10.3.2.4.1.

Table 11-44 – NACK reason codes
Value Definition

0116 Invalid set of vectoring feedback control parameters or vectoring feedback report format.
0216 Sending of vectoring feedback reports is stopped on the FTU-Os request (FTU-R received a
vectoring feedback command with the value of q = 0).
NOTE – All other reason codes are reserved by ITU-T.

11.2.2.15 Probe sequence update commands and responses

Upon instruction of the VCE, the FTU-O shall send the appropriate probe sequence update command to
force an update of the upstream probe sequence and communicate the new downstream probe sequence
for the line to the FTU-R FME. The commands are shown in Table 11-45 and Table 11-46, and may be
initiated only by the FTU-O. The FTU-R shall respond with either an ACK or NACK, using the format shown in
Table 11-47.

The first byte of the commands shall be the assigned value of the upstream and downstream probe
sequence update command type, as shown in Table 11-5. The second and subsequent bytes shall be as
shown in Table 11-45 and Table 11-46 for commands and in Table 11-47 for responses. The data bytes shall
be mapped using the format described in clause 11.2.2.1.
The command length depends on the length of the upstream probe sequence or downstream probe
sequence (Nprobe_us or Nprobe_ds, respectively) set during the initialization (see clause 12.3.3.2.1). Only
the probe sequence elements may be changed during the showtime. The length of the newly assigned
probe sequence shall be the same as the length of the probe sequence that was set during the initialization.

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