RHEL 6 ethtool does not show SFP laser optical diagnostics

Solution Verified - Updated -

Issue

  • Our Juniper switch shows SFP laser diagnostics like:
> show interfaces diagnostics optics ge-7/3/0
Physical interface: ge-7/3/0
    Laser bias current                        :  18.604 mA
    Laser output power                        :  0.2290 mW / -6.40 dBm
    Module temperature                        :  39 degrees C / 103 degrees F
    Module voltage                            :  3.3010 V
    Receiver signal average optical power     :  0.1808 mW / -7.43 dBm

RHEL 7 also shows similar optical information:

root@host# ethtool -m eth0
      Identifier                                : 0x03 (SFP)
      Optical diagnostics support               : Yes
      Laser bias current                        : 28.660 mA
      Laser output power                        : 0.7096 mW / -1.49 dBm
      Receiver signal average optical power     : 0.5711 mW / -2.43 dBm
      Module temperature                        : 55.98 degrees C / 132.76 degrees F

But RHEL 6 shows different output:

root@rhel6# ethtool -m eth3

        Identifier          : 0x03 (SFP)
        Extended identifier : 0x04 (GBIC/SFP defined by 2-wire interface ID)
        Connector           : 0x07 (LC)
        Transceiver codes   : 0x10 0x00 0x000x00 0x20 0x40 0x0c 0x80
                            :  => 10G Ethernet: 10G Base-SR
                            :  => FC: intermediate distance (I)
                            :  => FC: Shortwave laser w/o OFC (SN)
                            :  => FC: Multimode, 62.5um (M6)
                            :  => FC: Multimode, 50um (M5)
                            :  => FC: 1200 MBytes/sec
        Encoding            : 0x06 (64B/66B)
        BR, Nominal         : 10300MBd
        Rate identifier     : 0x00 (unspecified)
        Length (SMF,km)     : 0km
        Length (SMF)        : 0m
        Length (50um)       : 80m
        Length (62.5um)     : 30m
        Length (Copper)     : 0m
        Length (OM3)        : 300m
        Laser wavelength    : 850nm
        Vendor name         : Vendor
        Vendor OUI          : 00:12:34
        Vendor PN           : AAABBBCCC
        Vendor rev          : 2

Environment

  • Red Hat Enterprise Linux 6
  • ethtool command
  • NIC with optic fiber SFP

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