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2 Transport aspects
Table 12-3 – FTU-R state machine primitives
Primitive name Direction Valid state Description
r:_selftest_result FME ME R-SELFTEST Report of selftest result:
– pass;
– fail.
r:_idle_ignore ME FME Any state Request to move back to O-IDLE state.
r:_L0_request ME FME R-IDLE Request to move from O-IDLE state to O-SILENT state
R-SILENT or from O-SILENT state to O-INIT/HS state with
continuation to R-INIT/TRAIN state.
r:_init result FME ME R-INIT/HS Report on result of the ITU-T G.994.1 session:
– pass with mode selected;
– silent or no mode selected;
– fail.
r:_training_result FME ME R-INIT/TRAIN Reports the result of initialization (channel discovery
and channel analysis and exchange phases):
– pass;
– fail.
r:_end_showtime ME FME R-SHOWTIME Request to transition from R-SHOWTIME state to
R-INIT/TRAIN state upon conditions defined by fast-
retrain policy (see clause 12.1.4).
r:_L3_request FME ME R-SHOWTIME Request to transition to R-SILENT state through L3
request/grant eoc message exchange.
r:_L3_reject FME ME R-SHOWTIME Reject of the FTU-O request for transition to R-SILENT
state.
In the state diagrams for the FTU-O and FTU-R, O-IDLE and R-IDLE states, respectively, are defined. This
provides a quiet period, which may be useful for test purposes.
In the state diagrams for both the FTU-O and FTU-R, a self-test function is mandatory, but its content is
vendor discretionary. It is also a vendor discretionary option to define when self-test occurs (e.g., always at
power-up or only under FTU-O control), and which transition for an FTU-R to take after successfully
completing self-test (i.e., enter R-IDLE or enter R-SILENT state).
IDLE is the state where the FTU is provisioned through a management interface for the service desired by
the operator. In this state, the FTU does not transmit any signal. An FTU that receives a primitive from the
ME enabling it to activate (o:_L0_request for FTU-O or r:_L0_request for FTU-R) shall use the initialization
procedure defined in clause 12.3 to transition the link from the L3 state to the L0 state. An FTU enabled for
activation that detects initialization signals at the U reference point shall respond by using the initialization
procedure. If disabled, the FTU shall remain in the IDLE state.
The link transitions to the L0 state once the initialization procedure has completed successfully and both
FTUs are in the SHOWTIME state. Upon a guided power management (o:_L3_request, see clause 11.2.2.12),
the FTU-O shall enter the O-DEACTIVATING1 state and then return to the O-SILENT state. Upon a fast
retrain triggered by fast-retrain policy (see clause 12.1.4), the FTU-O shall enter O-DEACTIVATING2 state. In
both the O-DEACTIVATING1 state and the O-DEACTIVATING2 state, the FTU-O shall transmit quiet or idle
symbols at sync symbol positions and idle symbols (defined in clause 3.2.13) in all logical frames at RMC
symbol positions, at all NOI data symbol positions, and at all DOI symbol positions except symbol positions
that are beyond TBUDGET and those assigned for quiet symbols by parameters TIQ and TA (see
clause 10.7). The selection of the type of symbols during sync symbol positions is under VCE control.
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