The ethtool command enables you to query or control the network driver and hardware settings. It takes the device name (like swp1) as an argument. When the device name is the only argument to ethtool, it prints the current settings of the network device. See man ethtool(8) for details. Not all options are currently supported on switch port interfaces.

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Monitoring Interface Status Using ethtool

To check the status of an interface using ethtool:

cumulus@switch:~$ ethtool swp1
Settings for swp1:
        Supported ports: [ FIBRE ]
        Supported link modes:   1000baseT/Full
                                10000baseT/Full
        Supported pause frame use: No
        Supports auto-negotiation: No
        Advertised link modes:  1000baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: No
        Speed: 10000Mb/s
        Duplex: Full
        Port: FIBRE
        PHYAD: 0
        Transceiver: external
        Auto-negotiation: off
        Current message level: 0x00000000 (0)

        Link detected: yes

To query interface statistics:

cumulus@switch:~$ sudo ethtool -S swp1
NIC statistics:
        HwIfInOctets: 1435339
        HwIfInUcastPkts: 11795
        HwIfInBcastPkts: 3
        HwIfInMcastPkts: 4578
        HwIfOutOctets: 14866246
        HwIfOutUcastPkts: 11791
        HwIfOutMcastPkts: 136493
        HwIfOutBcastPkts: 0
        HwIfInDiscards: 0
        HwIfInL3Drops: 0
        HwIfInBufferDrops: 0
        HwIfInAclDrops: 28
        HwIfInDot3LengthErrors: 0
        HwIfInErrors: 0
        SoftInErrors: 0
        SoftInDrops: 0
        SoftInFrameErrors: 0
        HwIfOutDiscards: 0
        HwIfOutErrors: 0
        HwIfOutQDrops: 0
        HwIfOutNonQDrops: 0
        SoftOutErrors: 0
        SoftOutDrops: 0
        SoftOutTxFifoFull: 0
        HwIfOutQLen: 0

Viewing and Clearing Interface Counters

Interface counters contain information about an interface. You can view this information when you run cl-netstat, ifconfig, or cat /proc/net/dev. You can also use cl-netstat to save or clear this information:

cumulus@switch:~$ sudo cl-netstat
Kernel Interface table
Iface   MTU Met        RX_OK RX_ERR RX_DRP RX_OVR        TX_OK TX_ERR TX_DRP TX_OVR    Flg
---------------------------------------------------------------------------------------------
eth0   1500   0          611      0      0      0          487      0      0      0   BMRU
lo    16436   0            0      0      0      0            0      0      0      0    LRU
swp1   1500   0            0      0      0      0            0      0      0      0    BMU

cumulus@switch:~$ sudo cl-netstat -c
Cleared counters
OptionDescription
-c

Copies and clears statistics. It does not clear counters in the kernel or hardware.

The -c argument is applied per user ID by default. You can override it by using the -t argument to save statistics to a different directory.

-d

Deletes saved statistics, either the uid or the specified tag.

The -d argument is applied per user ID by default. You can override it by using the -t argument to save statistics to a different directory.

-DDeletes all saved statistics.
-lLists saved tags.
-rDisplays raw statistics (unmodified output of cl-netstat).
-t <tag name>Saves statistics with <tag name>.
-vPrints cl-netstat version and exits.

Monitoring Switch Port SFP/QSFP Hardware Information Using ethtool

To see hardware capabilities and measurement information on the SFP or QSFP module installed in a particular port, use the ethtool -m command. If the SFP/QSFP supports Digital Optical Monitoring (that is, the Optical diagnostics support field in the output below is set to Yes), the optical power levels and thresholds are also printed below the standard hardware details.

In the sample output below, you can see that this module is a 1000BASE-SX short-range optical module, manufactured by JDSU, part number PLRXPL-VI-S24-22. The second half of the output displays the current readings of the Tx power levels (Laser output power) and Rx power (Receiver signal average optical power), temperature, voltage and alarm threshold settings.

cumulus@switch$ sudo ethtool -m swp3
        Identifier                                : 0x03 (SFP)
        Extended identifier                       : 0x04 (GBIC/SFP defined by 2-wire interface ID)
        Connector                                 : 0x07 (LC)
        Transceiver codes                         : 0x00 0x00 0x00 0x01 0x20 0x40 0x0c 0x05
        Transceiver type                          : Ethernet: 1000BASE-SX
        Transceiver type                          : FC: intermediate distance (I)
        Transceiver type                          : FC: Shortwave laser w/o OFC (SN)
        Transceiver type                          : FC: Multimode, 62.5um (M6)
        Transceiver type                          : FC: Multimode, 50um (M5)
        Transceiver type                          : FC: 200 MBytes/sec
        Transceiver type                          : FC: 100 MBytes/sec
        Encoding                                  : 0x01 (8B/10B)
        BR, Nominal                               : 2100MBd
        Rate identifier                           : 0x00 (unspecified)
        Length (SMF,km)                           : 0km
        Length (SMF)                              : 0m
        Length (50um)                             : 300m
        Length (62.5um)                           : 150m
        Length (Copper)                           : 0m
        Length (OM3)                              : 0m
        Laser wavelength                          : 850nm
        Vendor name                               : JDSU            
        Vendor OUI                                : 00:01:9c
        Vendor PN                                 : PLRXPL-VI-S24-22
        Vendor rev                                : 1   
        Optical diagnostics support               : Yes
        Laser bias current                        : 21.348 mA
        Laser output power                        : 0.3186 mW / -4.97 dBm
        Receiver signal average optical power     : 0.3195 mW / -4.96 dBm
        Module temperature                        : 41.70 degrees C / 107.05 degrees F
        Module voltage                            : 3.2947 V
        Alarm/warning flags implemented           : Yes
        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
        Module voltage high alarm                 : Off
        Module voltage low alarm                  : Off
        Module voltage high warning               : Off
        Module voltage low warning                : Off
        Laser rx power high alarm                 : Off
        Laser rx power low alarm                  : Off
        Laser rx power high warning               : Off
        Laser rx power low warning                : Off
        Laser bias current high alarm threshold   : 10.000 mA
        Laser bias current low alarm threshold    : 1.000 mA
        Laser bias current high warning threshold : 9.000 mA
        Laser bias current low warning threshold  : 2.000 mA
        Laser output power high alarm threshold   : 0.8000 mW / -0.97 dBm
        Laser output power low alarm threshold    : 0.1000 mW / -10.00 dBm
        Laser output power high warning threshold : 0.6000 mW / -2.22 dBm
        Laser output power low warning threshold  : 0.2000 mW / -6.99 dBm
        Module temperature high alarm threshold   : 90.00 degrees C / 194.00 degrees F
        Module temperature low alarm threshold    : -40.00 degrees C / -40.00 degrees F
        Module temperature high warning threshold : 85.00 degrees C / 185.00 degrees F
        Module temperature low warning threshold  : -40.00 degrees C / -40.00 degrees F
        Module voltage high alarm threshold       : 4.0000 V
        Module voltage low alarm threshold        : 0.0000 V
        Module voltage high warning threshold     : 3.6450 V
        Module voltage low warning threshold      : 2.9550 V
        Laser rx power high alarm threshold       : 1.6000 mW / 2.04 dBm
        Laser rx power low alarm threshold        : 0.0100 mW / -20.00 dBm
        Laser rx power high warning threshold     : 1.0000 mW / 0.00 dBm
        Laser rx power low warning threshold      : 0.0200 mW / -16.99 dBm