13.1. Optical Signal StrengthΒΆ

Sometimes, it is necessary to check the optical signal strength after servers are installed and connected to switches. Here is an instruction on how to do this:

  1. Go to bash from vCGNAT CLI:

vCGNAT# start-shell bash

  1. Log in as root user:

nfwcli@vCGNAT:~$ sudo -i

  1. All vCGNAT interfaces are listed in the data namespace. Use the following command to switch to this namespace:

nfwcli@vCGNAT:~# ip netns exec data bash

  1. Find the physical interfaces. In the example below, the interfaces enp223s0f0np0 and enp221s0f0np0 are physically connected, and enp223s0f1np1 and enp221s0f0f1np1 are not because they have the NO-CARRIER state:

root@vCGNAT:~# ip a | grep enp
3: enp223s0f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
4: enp223s0f1np1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
5: enp221s0f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
6: enp221s0f1np1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000

  1. Use the ethtool utility with the -m key. Check the parameters Module voltage, Transmit avg optical power and Rcvr signal avg optical power:

root@vCGNAT:~# ethtool -m enp223s0f0np0
Identifier                                : 0x11 (QSFP28)
Extended identifier                       : 0x98
Extended identifier description           : 2.5W max. Power consumption
Extended identifier description           : CDR present in TX, No CDR in RX
Extended identifier description           : High Power Class (> 3.5 W) not enabled
Power set                                 : Off
Power override                            : On
Connector                                 : 0x07 (LC)
Transceiver codes                         : 0x80 0x00 0x00 0x00 0x00 0x00 0x00 0x00
Transceiver type                          : 100G Ethernet: 100G Base-LR4
Encoding                                  : 0x05 (64B/66B)
BR, Nominal                               : 25500Mbps
Rate identifier                           : 0x00
Length (SMF,km)                           : 10km
Length (OM3 50um)                         : 0m
Length (OM2 50um)                         : 0m
Length (OM1 62.5um)                       : 0m
Length (Copper or Active cable)           : 0m
Transmitter technology                    : 0x40 (1310 nm DFB)
Laser wavelength                          : 1310.000nm
Laser wavelength tolerance                : 1.000nm
Vendor name                               : NEOROS
Vendor OUI                                : 00:17:6a
Vendor PN                                 : QSFP100G-LR4-LC2
Vendor rev                                : 04
Vendor SN                                 : Y202302270867
Date code                                 : 230216
Revision Compliance                       : SFF-8636 Rev 2.5/2.6/2.7
Module temperature                        : 48.24 degrees C / 118.83 degrees F
Module voltage                            : 3.2756 V
Alarm/warning flags implemented           : Yes
Laser tx bias current (Channel 1)         : 47.946 mA
Laser tx bias current (Channel 2)         : 47.946 mA
Laser tx bias current (Channel 3)         : 47.946 mA
Laser tx bias current (Channel 4)         : 47.946 mA
Transmit avg optical power (Channel 1)    : 1.3635 mW / 1.35 dBm
Transmit avg optical power (Channel 2)    : 1.6003 mW / 2.04 dBm
Transmit avg optical power (Channel 3)    : 1.4453 mW / 1.60 dBm
Transmit avg optical power (Channel 4)    : 1.5603 mW / 1.93 dBm
Rcvr signal avg optical power(Channel 1)  : 0.8955 mW / -0.48 dBm
Rcvr signal avg optical power(Channel 2)  : 0.8311 mW / -0.80 dBm
Rcvr signal avg optical power(Channel 3)  : 0.8368 mW / -0.77 dBm
Rcvr signal avg optical power(Channel 4)  : 0.8286 mW / -0.82 dBm
Laser bias current high alarm   (Chan 1)  : Off
Laser bias current low alarm    (Chan 1)  : Off
Laser bias current high warning (Chan 1)  : Off
Laser bias current low warning  (Chan 1)  : Off
Laser bias current high alarm   (Chan 2)  : Off
Laser bias current low alarm    (Chan 2)  : Off
Laser bias current high warning (Chan 2)  : Off
Laser bias current low warning  (Chan 2)  : Off
Laser bias current high alarm   (Chan 3)  : Off
Laser bias current low alarm    (Chan 3)  : Off
Laser bias current high warning (Chan 3)  : Off
Laser bias current low warning  (Chan 3)  : Off
Laser bias current high alarm   (Chan 4)  : Off
Laser bias current low alarm    (Chan 4)  : Off
Laser bias current high warning (Chan 4)  : Off
Laser bias current low warning  (Chan 4)  : 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 tx power high alarm   (Channel 1)   : Off
Laser tx power low alarm    (Channel 1)   : Off
Laser tx power high warning (Channel 1)   : Off
Laser tx power low warning  (Channel 1)   : Off
Laser tx power high alarm   (Channel 2)   : Off
Laser tx power low alarm    (Channel 2)   : Off
Laser tx power high warning (Channel 2)   : Off
Laser tx power low warning  (Channel 2)   : Off
Laser tx power high alarm   (Channel 3)   : Off
Laser tx power low alarm    (Channel 3)   : Off
Laser tx power high warning (Channel 3)   : Off
Laser tx power low warning  (Channel 3)   : Off
Laser tx power high alarm   (Channel 4)   : Off
Laser tx power low alarm    (Channel 4)   : Off
Laser tx power high warning (Channel 4)   : Off
Laser tx power low warning  (Channel 4)   : Off
Laser rx power high alarm   (Channel 1)   : Off
Laser rx power low alarm    (Channel 1)   : Off
Laser rx power high warning (Channel 1)   : Off
Laser rx power low warning  (Channel 1)   : Off
Laser rx power high alarm   (Channel 2)   : Off
Laser rx power low alarm    (Channel 2)   : Off
Laser rx power high warning (Channel 2)   : Off
Laser rx power low warning  (Channel 2)   : Off
Laser rx power high alarm   (Channel 3)   : Off
Laser rx power low alarm    (Channel 3)   : Off
Laser rx power high warning (Channel 3)   : Off
Laser rx power low warning  (Channel 3)   : Off
Laser rx power high alarm   (Channel 4)   : Off
Laser rx power low alarm    (Channel 4)   : Off
Laser rx power high warning (Channel 4)   : Off
Laser rx power low warning  (Channel 4)   : Off
Laser bias current high alarm threshold   : 110.000 mA
Laser bias current low alarm threshold    : 1.000 mA
Laser bias current high warning threshold : 100.000 mA
Laser bias current low warning threshold  : 1.000 mA
Laser output power high alarm threshold   : 5.6234 mW / 7.50 dBm
Laser output power low alarm threshold    : 0.1862 mW / -7.30 dBm
Laser output power high warning threshold : 2.8184 mW / 4.50 dBm
Laser output power low warning threshold  : 0.3715 mW / -4.30 dBm
Module temperature high alarm threshold   : 80.00 degrees C / 176.00 degrees F
Module temperature low alarm threshold    : -10.00 degrees C / 14.00 degrees F
Module temperature high warning threshold : 70.00 degrees C / 158.00 degrees F
Module temperature low warning threshold  : 0.00 degrees C / 32.00 degrees F
Module voltage high alarm threshold       : 3.5000 V
Module voltage low alarm threshold        : 3.1000 V
Module voltage high warning threshold     : 3.4650 V
Module voltage low warning threshold      : 3.1350 V
Laser rx power high alarm threshold       : 5.6234 mW / 7.50 dBm
Laser rx power low alarm threshold        : 0.0437 mW / -13.60 dBm
Laser rx power high warning threshold     : 2.8184 mW / 4.50 dBm
Laser rx power low warning threshold      : 0.0871 mW / -10.60 dBm