N9K-M4PC-CFP2 reporting bogus values for Tx/Rx power of modules with NX-OS 9.3.7

ss1 · ‎07-12-2021

Hello,

We have a Nexus9000 C9396PX Chassis with a N9K-M4PC-CFP2 uplink board (4x100G CFP2).

It used to work okay until we upgraded the NX-OS from 7 to 9. The current NX-OS version is 9.3.7 and now our transceiver details are being wrongly reported with bogus values.

The Rx/Tx power were displayed without any trouble prior to our upgrade to ver.9 however it's now shown as below.

Wonder if anybody ever had the same issue?

Ethernet2/1
    transceiver is present
    type is CFP-100G-LR4
    name is FINISAR CORP.
    part number is FTLC1121RDNL
    revision is 15
    serial number is ..................
    nominal bitrate is 25800 MBit/sec per channel
    Link length supported for 9/125um fiber is 10 km
    cisco id is 17
    cisco extended id number is 164

Lane Number:1 Network Lane
Lane Number:1 Common Diagnostic Information
           CFP Detail Diagnostics Information (no calibration needed)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   36.85 C        70.00 C      0.00 C     68.00 C        2.00 C
  Voltage        3.21 V         3.46 V      3.13 V      3.43 V        3.16 V
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:2 Network Lane
           CFP Detail Diagnostics Information (no calibration needed)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   49.94 C        57.00 C     25.00 C     55.00 C       27.00 C
  Current       52.90 mA       70.00 mA    30.00 mA    65.00 mA      35.00 mA
  Tx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Rx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:3 Network Lane
           CFP Detail Diagnostics Information (no calibration needed)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   49.90 C        57.00 C     25.00 C     55.00 C       27.00 C
  Current       52.90 mA       70.00 mA    30.00 mA    65.00 mA      35.00 mA
  Tx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Rx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:4 Network Lane
           CFP Detail Diagnostics Information (no calibration needed)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   49.94 C        57.00 C     25.00 C     55.00 C       27.00 C
  Current       52.90 mA       70.00 mA    30.00 mA    65.00 mA      35.00 mA
  Tx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Rx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Lane Number:5 Network Lane
           CFP Detail Diagnostics Information (no calibration needed)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   49.94 C        57.00 C     25.00 C     55.00 C       27.00 C
  Current       52.90 mA       70.00 mA    30.00 mA    65.00 mA      35.00 mA
  Tx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Rx Power     -4232332.-555115576 dBm     -4232332.-555115576 dBm  -4232332.-555115576 dBm  -4232332.-555115576 dBm    -4232332.-555115576 dBm
  Transmit Fault Count = 0
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

Thank you.

Sergiu.Daniluk · ‎07-15-2021

Definitely looks like a cosmetic bug. I know this might not be easy to do, but did you tried to OIR the CFP?

Cheers,

Sergiu

ss1 · ‎09-18-2021

Sorry what does it mean to OIR the CFP? To replace / RMA it? If so, I have reproduced this on 3 different M4PC and 7 different CFP2 modules.

Thank you.

Sergiu.Daniluk · ‎09-18-2021

By OIR I mean to reseat it - to eject it and insert it back.

Stay safe,

Sergiu

ss1 · ‎09-18-2021

Dear Sergiu,

I even tried replacing the module, power cycling the switch, then I tried on a different M4PC board and on a different 9396 switch.
These bogus values are seen on NX-OS 9 but not on NX-OS 7.

Thank you.

Sergiu.Daniluk · ‎09-19-2021

I've searched for any known defects about CFP-100G SFPs and wrong power values, but there is nothing out there. Opening a case for this platform will also not help since its EoL: https://www.cisco.com/c/en/us/products/collateral/switches/nexus-9000-series-switches/eos-eol-notice-c51-739452.html

I think you have two options: stay with 9.x for specific features or fixes present in 9.x or, if you do not have any specific reasons to stay on 9.x, downgrade to 7.x

Cheers,

Sergiu