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Optical Transport Network (OTN) Interfaces

 

The QFX10K-12C-DWDM line card supports the optical transport interfaces (OTN) which is used for high end packet forwarding by cloud providers, service providers and enterprises. There are various optic-specific options that can be configured on the QFX10K-12C-DWDM line card including the forward error correction (FEC) mode and enabling the threshold crossing alarms.

Understanding the QFX10K-12C-DWDM Line Card

The QFX10000-12C-DWDM line card provides up to 1.2 Tbps packet forwarding for cloud providers, service providers, and enterprises that need coherent dense wavelength-division multiplexing (DWDM) with MACsec security features.

The QFX10K-12C-DWDM line card is supported on Junos OS Release 17.2R1 and later.

The following sections explain the features of the QFX10K-12C-DWDM line card in detail:

Software Features

The following interface features are supported on the QFX10000-12C-DWDM:

  • Compliant with ITU G.709 and G.798

  • Performance monitoring features such as alarms, threshold-crossing alarms, OTU/ODU error seconds, and FEC and bit error rate (BER) statistics.

  • SNMP management of the MIC based on RFC 3591, Managed Objects for the Optical Interface Type, including the following:

    • Black Link MIB–jnx-bl.mib

    • IFOTN MIB–jnx-ifotn.mib

    • Optics MIB–jnx-optics.mib

    • FRU MIB–jnx-fru.mib

  • User-configurable optics options:

    • Modulation format: 16QAM, 8QAM, QPSK

    • FEC mode (15% SDFEC or 25% SDFEC)

    • Differential and non-differential encoding modes

    • Transmit (TX) laser enable and disable

    • TX output power

    • Wavelength

    • Threshold crossing alarms (TCAs)

  • IEEE 802.1ag OAM

  • IEEE 802.3ah OAM

  • IFINFO/IFMON

  • IEEE 802.3ad link aggregation

  • Flexible Ethernet services encapsulation

  • Flexible VLAN tagging

  • Source address MAC accounting per logical interface

  • Source address MAC filter per port

  • Source address MAC filter per logical interface

  • Destination address MAC filter per port

  • Up to 8000 logical interfaces shared across all ports on a single PFE

OTN Alarms and Defects

The following OTN alarms and defects are supported on the QFX10K-12C-DWDM line card:

Optical Channel(OC) Alarms and Defects

  • OC-LOS—Loss Of Signal

  • OC-LOF—Loss Of Frame

  • OC-LOM—Loss Of Multiframe

  • OC-Wavelength-Lock—Wavelength Lock

Optical Channel Data Unit (ODU) Defects

  • ODU-AIS—ODU Alarm Indication Signal

  • ODU-BDI—ODU Backward Defect Indication

  • ODU-IAE—ODU Incoming Alignment Error

  • ODU-LCK—ODU Locked

  • ODU-LTC—ODU Loss of Tandem Connection

  • ODU-OCI—ODU Open Connection Error

  • ODU-SSF—ODU Server Signal Failure

  • ODU-TSF—ODU Trail Signal Failure

  • ODU-TTIM—ODU Trail Trace Identifier Mismatch

Optical Channel Transport Unit (OTU) Defects

  • OTU-AIS—OTU Alarm Indication Signal

  • OTU-BDI—OTU Backward Defect Indication

  • OTU-BIAE—OTU Backward Incoming Alignment Error

  • OTU-FEC-DEG—OTU Forward Error Correction Degrade

  • OTU-FEC-EXCESS-FEC—OTU Forward Error Correction Excessive FEC Errors

  • OTU-IAE—OTU Incoming Alignment Error

  • OTU-SSF—OTU Server Signal Failure

  • OTU-TSF—OTU Trail Signal Failure

  • OTU-TTIM—OTU Trail Trace Identifier Mismatch

Threshold-Crossing Alarms

Threshold-crossing alarms (TCA) are alarms that are activated when a certain configurable threshold —near-end measurement threshold or far-end measurement threshold—is crossed and remains so until the end of the 15 minutes interval for parameters such as OTU and ODU. The following alarms are supported:

  • Background block error threshold (BBE)

  • Errored seconds threshold (ES)

  • Severely errored seconds threshold (SES)

  • Unavailable seconds threshold (UES)

Configuring OTN Interface Options on QFX10K-12C-DWDM

The QFX10000-12C-DWDM line card provides up to 1.2 Tbps packet forwarding for cloud providers, service providers, and enterprises that need coherent dense wavelength-division multiplexing (DWDM) with MACsec security features. The QFX10K-12C-DWDM line card is supported on Junos OS Release 17.2R1 and later.

Each QFX10K-12C-DWDM has 6 physical interfaces (ot-x/x/x) that connect to one of three built-in flexible rate optical transponders. Each transponder connects four 100-Gigabit Ethernet logical interfaces (et-x/x/x) to one of three forwarding ASICs.

To configure the optics-specific options on the interface:

  1. Specify the modulation format at the [edit interface interface-name optics-options] hierarchy level.
  2. Specify encoding.
  3. Specify the optical transmit laser output power in dBm. The default transmit laser output value is 0 dBm.
  4. Specify the wavelength of the optics in nanometers. For a list of wavelengths supported, see wavelength.

To configure the OTN-specific options on the interface:

  1. At the [edit interfaces interface-name otn-options] enable the laser on the OTN interface. The laser is disabled by default for all OTN interfaces.
  2. Set an trail trace identifier for the source access point and for the destination access point for ODU and OTU on the OTN interface.
  3. By default, triggers are ignored. Specify defect triggers and the set the trigger hold time for the trigger. Possible values for the trigger hold time are as follows: down—Delay before marking interface down when defect occurs (1..65534 milliseconds) and up—Delay before marking interface up when defect is absent (1..65534 milliseconds). Note

    The hold time value only impacts the alarm reporting time and does not mark an interface down when the defect occurs. To mark the interface up or down, you must also configure the physical interface hold time at the [edit interfaces interface-name] hierarchy level.

  4. Enable the threshold crossing alarms for the OTN interface along with the trigger for the defect.
  5. Set the OTN header bytes as a transmit payload type from 0 bytes through 255 bytes for the packets that are transmitted on the OTN interface.
  6. Configure the forward error correction (FEC) mode for the OTN interface. Possible values are: Generic Forward Error Correction (GFEC), or High Gain Forward Error Correction (HGFEC) or Soft Decision Forward Error Correction (SDFEC). The default forward error correction mode is SDFEC.
  7. Enable line loopback or local host loopback for the OTN interface.
  8. Enable an ODU locked maintenance signal on the OTN interface to send the signal pattern 01010101.
  9. Enable an ODU open connection indication signal on the OTN interface to send to send the signal pattern 01100110.
  10. Enable a consequent action as listed in the ITU-T G.798 standard for ODU trail trace identifier mismatch (TTIM) on the OTN interface.
  11. Enable a consequent action as listed in the ITU-T G.798 standard for OTU trail trace identifier mismatch (TTIM) on the OTN interface.
  12. Configure the OTN payload pseudorandom binary sequence (PRBS) on the OTN interface.
  13. Configure the line rate or speed of the OTN signal to OTU4 (100Gbps) for the OTN interface. Note

    If you specify a value other than OTU4, the value is ignored. To verify the line rate, use the show interfaces interface-name extensive command.

  14. Configure the threshold value for signal degradation when an alarm needs to be raised. Configure the threshold value after signal degradation when the alarm needs to be cleared. When you configure the interval along with the ber-threshold-signal-degrade value statement, the bit error rate (BER) must stay above the signal degradation threshold for the configured interval after which the alarm is raised. When the interval is configured along with the ber-threshold-clear value statement, then BER must stay below the clear threshold for the configured interval after which the alarm is cleared.
  15. Enable the following actions for the preemptive-fast-reroute statement:
    • Backward FRR—Insert the local pre-FEC status into the transmitted OTN frames and monitor the received OTN frames for the pre-FEC status.

    • ODU backward FRR—Insert the ODU status into the transmitted OTN frames and monitor the received OTN frames for the ODU BER status.

    • Monitoring of signal degradation of pre-FEC OTN frames.

    • Monitoring of signal degradation of ODU BER in the received OTN frames.

  16. Configure the following options for ODU BER signal degradation on the OTN interface:

    • Configure the threshold for signal degradation for ODU BER when an alarm needs to be raised.

    • Configure the threshold for ODU BER after signal degradation when the alarm needs to be cleared.

    • When you configure the interval along with the ber-threshold-signal-degrade value statement, the ODU bit error rate (BER) must stay above the signal degradation threshold for the configured interval after which the alarm is raised. When the interval is configured along with the ber-threshold-clear value statement, then ODU BER must stay below the clear threshold for the configured interval after which the alarm is cleared.