Page 897 - 5G Basics - Core Network Aspects

Transport aspects 2

back to the R-SHOWTIME state. If the initialization sequence is aborted (per conditions defined in
clause 12.1.1), then the FTU-R transitions to the R-SILENT state.

The following fast retrain policy is defined for the L0 link state:
• Policy ZERO
If FRpolicy = 0, then:
Fast retrain shall be triggered when at least one of the following fast retrain policy triggers is declared:

1) persistent near-end los defect; or
2) persistent near-end lom defect; or
3) persistent near-end lor defect ; or
4) a high_BER event.

The following fast retrain policy is defined for the L2.1 link state:
• Policy ZERO
If L2.1-FRpolicy = 0, then:

Fast retrain shall be triggered when at least one of the following fast retrain policy triggers is declared:
1) persistent near-end los defect; or
2) persistent near-end lor defect; or
3) a high_BER event (see Table 12-6) with no trigger on the ETR threshold.

The following fast retrain policy is defined for the L2.2 link state:
• Policy ZERO
If L2.2-FRpolicy = 0, then:

Fast retrain shall be triggered when at least one of the following fast retrain policy triggers is declared:
1) persistent near-end lor defect; or
2) there have been 5 consecutive eoc command timeouts without a single successful response.

12.1.4.3 Persistent link defects and high_BER events
12.1.4.3.1 Persistent near-end los defect

A persistent near-end los defect shall be declared after los_persistency milliseconds of continuous near-end
los defect (see clause 11.3.1.3). The control parameter los_persistency has valid values from 100 to 2 000 in
steps of 100, with a default value of 200.

The los_persistency defined for the downstream and upstream are denoted as los_persistency-ds and
los_persistency-us, respectively.

The control parameter los_persistency is configured through the DPU-MIB configuration parameter
LOS_PERSISTENCY.

NOTE – The persistency allows the transmitting FTU to detect the los defect condition through the indicator bits,
before the receiving FTU leaves the SHOWTIME state.

12.1.4.3.2 Persistent near-end lom defect
A persistent near-end lom defect shall be declared after lom_persistency seconds of continuous near-end
lom defect (see clause 11.3.1.3). The control parameter lom_persistency has valid values from 1 to 20 in
steps of 1, with a default value of 2.
The lom_persistency defined for the downstream and upstream are denoted as lom_persistency-ds and
lom_persistency-us, respectively.

887