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Link Degrade Monitoring Overview


Link degrade monitoring enables you to monitor the quality of physical links on Ethernet interfaces (10-Gigabit, 40-Gigabit, and 100-Gigabit) and take corrective action when the link quality degrades beyond a certain level. You can configure this feature by applying the link-degrade-monitor statement at the [edit interfaces interface-name] hierarchy level. When configured on your device, this feature continuously monitors bit error rate (BER) value of the link and initiates a corrective action (media-based) when the BER value breaches a user-configured threshold. The feature can detect a BER value as low as 10-13 through 10-5, helping you prevent or minimize packet drops in physical links.

You can configure autorecovery or manual recovery method for the degraded link. In the case of manual recovery, you need to use the request interface link-degrade-recover interface-name statement to recover the degraded link. If autorecovery is configured, automatic recovery of the degraded link is attempted at the user configured intervals, and when the link’s BER value is within the configured limit, the link is recovered.


Layer 2 and Layer 3 protocols already support physical link monitoring. So do Ethernet links through the Link Fault Signaling (LFS) protocol. However, these existing mechanisms cannot detect BER ranges that are very low (for example, 10-13 through 10-5).

Supported Platforms

Table 1 lists the platform series and line cards that support link degrade monitoring.

Table 1: Line Cards that Support Link Degrade Monitoring

Platform Series

MPC Line Cards Supported

DPC Line Cards Supported


  • MPC4E-3D-2CGE-8XGE


  • MPC-3D-16XGE-SFP

  • MPC3 with MIC3-3D-1X100GE-CFP

  • MPC3 with MIC3-3D-2X40GE-QSFPP

  • MPC3 with MIC-3D-2XGE-XFP

  • MPC3 with 2x10GE XFP MIC

  • MPC3 with 2x10GE XFP MIC

  • MPC5 with following variants:

    • 2CGE + 4XGE

    • 24XGE + 6XLGE

  • MPC6 with the following variants:

    • 2X100GE CFP2

    • 24X10GE SFPP

    • 24X10GE SFPP OTN

    • 4x100GE CXP


  • MPC7E-10G (non-MACsec mode)



    Note: Link degrade monitoring is not supported on MACsec-enabled MPC7E-10G and MIC-MACSEC-MRATE.

  • MPC10E-10C-MRATE (10G, 40G, and 100G interfaces)

  • MPC10E-15C-MRATE (10G, 40G, and 100G interfaces)








On 10-Gigabit Ethernet interfaces:

  • DPCE-R-Q-20GE-2XGE

  • DPCE-R-20GE-2XGE

  • DPCE-X-20GE-2XGE