Statement introduced in Junos OS Release 13.2 for PTX Series routers.
Statement introduced in Junos OS Release 15.1F6 for MPC5E, MIC6-100G-CFP2 on MPC6E on MX240, MX480, MX960, MX2010, and MX2020 routers.
Specify the bit error rate (BER) threshold to raise an interface alarm for signal degradation.
You can configure the BER signal degrade threshold to customize the BER that will raise an interface alarm when signal degrade monitoring is enabled.
Configuring a high BER threshold for signal degradation
and a long interval might cause the internal bit error counter register
to get saturated. For example, for the P1-PTX-2-100G-WDM PIC, the
internal bit error counter gets saturated when the error count reaches
2E+29. Therefore, the value of
* line rate / interval must be less than 2E+29 to avoid
saturation. Assuming a fixed PIC line rate of 1.27E+11 bits per second
and an interval of 1000 ms, the ber-threshold-signal-degrade value must be less than 4.22E–3.
If the value of the
* line rate / interval exceeds the saturation limit, the
configuration is ignored by the router, and the default values are
used instead. A system log message is logged for this error.
If you configure the BER thresholds at the [edit interfaces interface-name otn-options signal-degrade] hierarchy level, then the thresholds are calculated using the pre-forward error correction (pre-FEC) BER (the BER before FEC correction). These thresholds are used for pre-FEC BER monitoring. See Understanding Pre-FEC BER Monitoring and BER Thresholds for more information about pre-FEC BER monitoring and determining BER threshold settings.
If you configure the BER thresholds at the [edit interfaces interface-name otn-options odu-signal-degrade] hierarchy level, then the thresholds are calculated using the post-FEC BER (the BER after FEC correction). This BER is referred to as the optical channel data unit (ODU) BER.
Table 1 shows the default values for pre-FEC BER and ODU BER signal degrade threshold values for different PICs. If the BER signal degrade threshold is not configured, the default value is used.
Table 1: Default Signal Degrade Threshold Values
PIC or MPC
Default Pre-FEC BER Signal Degrade Threshold Value
Default ODU BER Signal Degrade Threshold Value
To configure the threshold that clears the signal degrade alarm, include the ber-threshold-clear statement at the same hierarchy level. To configure the time interval during which the BER must stay above or below the configured thresholds to raise or clear the alarm, include the interval statement at the same hierarchy level.
For the P1-PTX-2-100G-WDM PIC, the BER must stay above the signal degradation threshold for ten consecutive intervals for the alarm to be raised and the BER must stay below the clear threshold for ten consecutive intervals for the alarm to be cleared. For example, if the interval is configured as 10 ms, then the BER must stay above the signal degradation threshold for 100 ms (10 ms * 10 intervals) for the alarm to be raised, or below the clear threshold for 100 ms for the alarm to be cleared.
value—BER threshold for signal degradation in scientific notation. Both the mantissa and exponent are configurable. Enter the value in the format xE–n, where x is the mantissa and n is the exponent. For example, 4.5E–3.
Range: The mantissa must be a decimal number. There is no limit on the number of digits before or after the decimal point.
The exponent must be an integer from 0 through 9.
Default: See Table 1.
In Junos OS Release 13.2R1, only the exponent is valid input for the BER threshold value, the mantissa is not configurable. The BER threshold value is 1.0E–n where n > 0, and the valid range of n is from 1 through 10.
To enable proactive protection before packet loss occurs, set the ber-threshold-signal-degrade value below the FEC limit. For the FEC limits, see the table describing the signal degrade and clear thresholds after configuration in Understanding Pre-FEC BER Monitoring and BER Thresholds.
Required Privilege Level
interface—To view this statement in the configuration.
interface-control—To add this statement to the configuration.