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Cisco Bug: CSCvh95972 - CLI "fec rs-fec" should not be accepted for 100g LR4 optics

Last Modified

Oct 09, 2019

Products (52)

  • Cisco Nexus 9000 Series Switches
  • Cisco Nexus 3548-X Switch
  • Cisco Nexus 3548 Switch
  • Cisco Nexus 9516 Switch
  • Cisco Nexus 3132Q-V Switch
  • Cisco Nexus 93108TC-FX Switch
  • Cisco Nexus 92304QC Switch
  • Cisco Nexus 31108TC-V Switch
  • Cisco Nexus 3548-XL Switch
  • Cisco Nexus 92160YC-X Switch
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Known Affected Releases


Description (partial)

The LR4 transceiver such as QSFP-100G-LR4-S does not support fec and is internally set to fec off.
However, fec rs-fec can be configured, which is misleading.   Change is to disallow the CLI fec rs-fec
for this transceiver type.

When user configures fec rs-fec on a physical interface that has the LR4 optics,
the command is rejected.    When an ascii startup-config already has this CLI,
the command, the command is rejected.   When a saved config file has this CLI,
the operation of "configure replace <saved file>" can fail at this command.
In this case, user has to manually edit and remove this CLI from the saved config.

This command exists when LR4 optics was deployed.   Only in a H image, the CLI is
rejected.   It is applicable to N9K and N3K switches that use the LR4 optics.
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