Page 832 - 5G Basics - Core Network Aspects

2 Transport aspects

TPS_TESTMODE command, the FTU-R shall acknowledge it with an ACK response. Afterwards, the FTU-R
shall set TPS_TESTMODE enabled. Upon reception of the leave TPS_TESTMODE command, the FTU-R shall
set TPS_TESTMODE disabled. The generation of DTUs is as specified in clause 8.3.1.
11.2.2.7 NTR frequency synchronization command

If NTR transport is enabled during the initialization, NTR frequency synchronization eoc commands
(presented in Table 11-24) shall be sent by the FTU-O and used by the FTU-R to facilitate NTR frequency
synchronization as described in clause 8.4.1. If NTR transport is disabled during the initialization, the FTU-O
shall not send NTR synchronization commands during the showtime.
The FTU-R shall not send a response to the NTR synchronization command.

The NTR frequency synchronization command is a near-high priority command. The first byte of the
command shall be the command type assigned as shown in Table 11-4 (NTR frequency synchronization
command). The remaining bytes of the command shall be as specified in Table 11-24.

The FTU-O shall always send the most recent NTR frequency synchronization command and shall discard all
older NTR frequency synchronization commands.
NOTE – Since no response is defined, the FTU-O management entity will not retransmit the lost NTR frequency
synchronization command.

Table 11-24 – NTR frequency synchronization command (sent by the FTU-O)

Length
Name Byte Content
(bytes)
NTR phase offset 6 2 0116 (Note 1)
3 and 4 Two bytes for the count of the superframe associated
with the event (Note 2).
5 and 6 Two bytes, representing the NTR phase offset value (φ) as
defined in clause 8.4.1.1.
NOTE 1 – All other values for byte 2 are reserved by ITU-T.
NOTE 2 – The value shall be even.
If the FTU-O indicates during the initialization that its PMD sampling frequency is locked to NTR, as
described in clause 8.4.1, the NTR synchronization command shall not be sent by the FTU-O and shall be
ignored by the FTU-R.

11.2.2.8 ToD frequency synchronization command

The ToD frequency synchronization command shall only be used in one direction, from FTU-O to FTU-R. The
FTU-R shall not send a response to a ToD frequency synchronization command. The ToD frequency
synchronization command shall be used if frequency synchronization using ToD phase difference is selected
during the initialization; if frequency synchronization through locking the PMD sample clock is selected
during the initialization, the ToD frequency synchronization command shall not be used (see clause 8.5.2).

The ToD frequency synchronization command is a near-high priority command. The first byte of the
command shall be the command type assigned as shown in Table 11-4 (ToD frequency synchronization
command). The remaining bytes of the command shall be as specified in Table 11-25.
The ToD phase difference value and corresponding t1 event number shall be encapsulated in a ToD
frequency synchronization command using the format defined in clause 8.5.2.1 as follows:

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