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We have been facing an issue on Juniper MX series router. We have 10G interface on our router. Its does not matter whether interface is connected to DWDM or interface itself is a dark fiber. The end issue is same.

The issue being that 10G interface stops transmitting output optical power while the XFP / SFP+ is getting received optical power. This is observed using the output of cli command ' show interface diagnostics optics '.

Below is the output of interface under this situation.

Physical interface: xe-3/3/0
    Laser bias current                        :  0.000 mA
    Laser output power                        :  0.0000 mW / - Inf dBm <----
    Module temperature                        :  29 degrees C / 85 degrees F
    Laser rx power                            :  0.0086 mW / -20.66 dBm
    Laser bias current high alarm             :  Off
    Laser bias current low alarm              :  On
    Laser bias current high warning           :  Off
    Laser bias current low warning            :  On
    Laser output power high alarm             :  Off
    Laser output power low alarm              :  On
    Laser output power high warning           :  Off
    Laser output power low warning            :  On
    Module temperature high alarm             :  Off
    Module temperature low alarm              :  Off
    Module temperature high warning           :  Off
    Module temperature low warning            :  Off
    Laser rx power high alarm                 :  Off
    Laser rx power low alarm                  :  On
    Laser rx power high warning               :  Off
    Laser rx power low warning                :  On
    Module not ready alarm                    :  Off
    Module power down alarm                   :  Off
    Tx data not ready alarm                   :  Off
    Tx not ready alarm                        :  Off
    Tx laser fault alarm                      :  Off
    Tx CDR loss of lock alarm                 :  Off
    Rx not ready alarm                        :  On
    Rx loss of signal alarm                   :  Off
    Rx CDR loss of lock alarm                 :  Off

Now if try to bounce the interface using 'set interface xe-3/3/0 disable' followed by commit and 'delete interface xe-3/3/0 disable' again followed by commit, the interface starts transmitting output power.

Physical interface: xe-3/3/0
    Laser bias current                        :  41.372 mA
    Laser output power                        :  1.1160 mW / 0.48 dBm <----
    Module temperature                        :  30 degrees C / 85 degrees F
    Laser rx power                            :  0.0088 mW / -20.56 dBm
    Laser bias current high alarm             :  Off
    Laser bias current low alarm              :  Off
    Laser bias current high warning           :  Off
    Laser bias current low warning            :  Off
    Laser output power high alarm             :  Off
    Laser output power low alarm              :  Off
    Laser output power high warning           :  Off
    Laser output power low warning            :  Off
    Module temperature high alarm             :  Off
    Module temperature low alarm              :  Off
    Module temperature high warning           :  Off
    Module temperature low warning            :  Off
    Laser rx power high alarm                 :  Off
    Laser rx power low alarm                  :  On
    Laser rx power high warning               :  Off
    Laser rx power low warning                :  On
    Module not ready alarm                    :  On
    Module power down alarm                   :  Off
    Tx data not ready alarm                   :  On
    Tx not ready alarm                        :  On
    Tx laser fault alarm                      :  Off
    Tx CDR loss of lock alarm                 :  On
    Rx not ready alarm                        :  On
    Rx loss of signal alarm                   :  Off
    Rx CDR loss of lock alarm                 :  Off

Need to understand under what circumstances interface stops transmitting output optical power? Why manual intervention is required for recovery? Based on observation , excessive interface flapping has been seen in the syslog messages on Juniper MX before this stage of no output power.

5
  • Normally, only a shut down interface doesn't transmit power.
    – Zac67
    Jan 11 at 13:29
  • But the interface was not shut down Jan 11 at 13:46
  • These questions are not related directly. Have you tried another transceiver? Is this a case where you're configuring interface speed on a channelized interface (i.e. QSFP 4x10)? Jan 11 at 14:53
  • @JordanHead. Didn't try another Transceiver. This is not a case of configuring interface speed on a channelized interface. Its simple standalone 10G interface. Jan 11 at 15:11
  • 1
    Check it the instant it stops. I've seen optics cut-out when they overheat. (by the time most people check them, they're back to normal)
    – Ricky
    Jan 11 at 15:19

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