This repository aims to collect some information about the very popular 100GBase-CWDM4 transceivers. Those transceivers are cheap, versatile (most can do 100G and 40G), and SMF (Single Mode Fiber) based which makes them very cheap to use.

The programmings directory contains the binary transceiver programmings as well as their decoded form (using my TransceiverTool) as text. The datasheets directory contains some datasheets for the transceivers.

List of 100G-CWDM4 transceivers

Name	Reprogrammable	Distance
Finisar FTLC1152RGPL6-FB	Yes, with password 0x00 0x00 0x10 0x11	500m
Finisar FTLC1157RGPL6FB1	Yes, with password 0x00 0x00 0x10 0x11	500m
Innolight TR-FC13H-HFB	No (Default password from other Innolight transceivers does not work)	500m
Intel SPTSBP2CLCKS	No (password unknown or not reprogrammable)	500m
Kaiam XQX5170	No (password unknown or not reprogrammable)	2km (from programming, no datasheet available)
Innolight TR-FC13T-NAZ	Yes, with password 0x00 0x00 0x10 0x11	2km

Transceiver Specific Notes

Finisar FTLC1152RGPL6-FB

In Revelprog-IS, go to password, select enter current password, then enter 00 00 10 11, click excute and then DESELECT Enter current password For some reason reprogramming will not work if Enter current password stays selected. Once unlocked, the transceiver will stay unlocked forever, even after power cycle!

The programming indicates 2km maximum distance, but this is false. The transceivers is a 100G-CWDM4 Lite and therefore 500m. The datasheet indicates that the 6 in FTLC1152RGPL6 means Lite reach (500m) and limited temperature range

Finisar FTLC1157RGPL6FB1

In Revelprog-IS, go to password, select enter current password, then enter 00 00 10 11, click excute and then DESELECT Enter current password For some reason reprogramming will not work if Enter current password stays selected. Once unlocked, the transceiver will stay unlocked forever, even after power cycle!

The programming indicates 2km maximum distance, but this is false. The transceivers is a 100G-CWDM4 Lite and therefore 500m. The datasheet indicates that the 6 in FTLC1152RGPL6 means Lite reach (500m) and limited temperature range

Innolight TR-FC13H-HFB

Surprisingly, this one does not use the expected QSFP default password 0x00 0x00 0x10 0x11. Current password unknown, or not reprogrammable at all

Running 100GBase-CWDM4 at 40G with Mellanox NICs

TL;DR: If you want to run 100GBase-CWDM4 transceivers at 40G with Mellanox NICs ConnectX-4 and newer (ConnectX-4, ConnectX-5, ConnectX-6) the transceiver MUST be programmed with the Mellanox OUI 00:02:c9, otherwise no link will be established (the card actively disables the laser!)

It can be desirable to run 100GBase-CWDM4 transceivers at 40GBit/s, e.g. to connect a server to a switch, as 100GBase-CWDM4 transceivers are often cheaper and better available than 40GBase-LR (or 40GBase-LR Lite) and allow an upgrade path to 100Gbit without buying new transceivers, making them a much better investment.

Sadly, this is not trivial if you have Mellanox NICs, specifically ConnectX-4 and newer (ConnectX-4, ConnectX-5, ConnectX-6).

As an example, we will use a Mellanox CX416A-CCAT (ConnectX-4 4x100G QSFP28, Firmware Version 12.28.2302) and Finisar FTLC1152RGPL6-FB transceivers. Let's force the ports to 40Gbit/s

ethtool -s ens16f1np1 speed 40000 duplex full autoneg off
ethtool -s ens16f0np0 speed 40000 duplex full autoneg off

(note that autoneg off or autoneg on does not make a difference).

We will be greeted with

ethtool ens16f1np1

Settings for ens16f1np1:
[...]
        Advertised link modes:  40000baseKR4/Full
                                40000baseCR4/Full
                                40000baseSR4/Full
                                40000baseLR4/Full
[...]
        Link detected: no (Cable issue, Unsupported cable)

Full ethtool ens16f1np1

ethtool ens16f1np1
Settings for ens16f1np1:
      Supported ports: [ FIBRE ]
      Supported link modes:   1000baseKX/Full
                              10000baseKR/Full
                              40000baseKR4/Full
                              40000baseCR4/Full
                              40000baseSR4/Full
                              40000baseLR4/Full
                              25000baseCR/Full
                              25000baseKR/Full
                              25000baseSR/Full
                              50000baseCR2/Full
                              50000baseKR2/Full
                              100000baseKR4/Full
                              100000baseSR4/Full
                              100000baseCR4/Full
                              100000baseLR4_ER4/Full
      Supported pause frame use: Symmetric
      Supports auto-negotiation: Yes
      Supported FEC modes: None        RS      BASER
      Advertised link modes:  40000baseKR4/Full
                              40000baseCR4/Full
                              40000baseSR4/Full
                              40000baseLR4/Full
      Advertised pause frame use: No
      Advertised auto-negotiation: No
      Advertised FEC modes: None       RS      BASER
      Speed: Unknown!
      Duplex: Unknown! (255)
      Auto-negotiation: off
      Port: FIBRE
      PHYAD: 0
      Transceiver: internal
      Supports Wake-on: d
      Wake-on: d
      Link detected: no (Cable issue, Unsupported cable)

Oh no! No link. If we look at the ethtool -m ens16f1np1 output we will see that the Mellanox card does actively disables the laser!

ethtool -m ens16f1np1

[...]
Transmit avg optical power (Channel 1)    : 0.0001 mW / -40.00 dBm
Transmit avg optical power (Channel 2)    : 0.0001 mW / -40.00 dBm
Transmit avg optical power (Channel 3)    : 0.0001 mW / -40.00 dBm
Transmit avg optical power (Channel 4)    : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 1)  : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 2)  : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 3)  : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 4)  : 0.0001 mW / -40.00 dBm
[...]

Solution: We need to reprogram the transceivers.

Right now they are looking like this:

ethtool -m ens16f1np1
[...]
Vendor name                               : FINISAR CORP.
Vendor OUI                                : 00:90:65
Vendor PN                                 : FTLC1152RGPL6-FB
[...]

Full ethtool -m ens16f1np1

ethtool -m ens16f1np1

Identifier                                : 0x11 (QSFP28)
Extended identifier                       : 0xcc
Extended identifier description           : 3.5W max. Power consumption
Extended identifier description           : CDR present in TX, CDR present 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 CWDM4 MSA with FEC
Encoding                                  : 0x07 ((256B/257B (transcoded FEC-enabled data))
BR, Nominal                               : 25500Mbps
Rate identifier                           : 0x02
Length (SMF,km)                           : 2km
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                          : 1301.000nm
Laser wavelength tolerance                : 6.500nm
Vendor name                               : FINISAR CORP.
Vendor OUI                                : 00:90:65
Vendor PN                                 : FTLC1152RGPL6-FB
Vendor rev                                : A0
Vendor SN                                 : UX503M0
Date code                                 : 170131
Revision Compliance                       : SFF-8636 Rev 2.5/2.6/2.7
Module temperature                        : 34.50 degrees C / 94.10 degrees F
Module voltage                            : 3.2706 V
Alarm/warning flags implemented           : Yes
Laser tx bias current (Channel 1)         : 0.000 mA
Laser tx bias current (Channel 2)         : 0.000 mA
Laser tx bias current (Channel 3)         : 0.000 mA
Laser tx bias current (Channel 4)         : 0.000 mA
Transmit avg optical power (Channel 1)    : 0.0001 mW / -40.00 dBm
Transmit avg optical power (Channel 2)    : 0.0001 mW / -40.00 dBm
Transmit avg optical power (Channel 3)    : 0.0001 mW / -40.00 dBm
Transmit avg optical power (Channel 4)    : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 1)  : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 2)  : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 3)  : 0.0001 mW / -40.00 dBm
Rcvr signal avg optical power(Channel 4)  : 0.0001 mW / -40.00 dBm
Laser bias current high alarm   (Chan 1)  : Off
Laser bias current low alarm    (Chan 1)  : On
Laser bias current high warning (Chan 1)  : Off
Laser bias current low warning  (Chan 1)  : On
Laser bias current high alarm   (Chan 2)  : Off
Laser bias current low alarm    (Chan 2)  : On
Laser bias current high warning (Chan 2)  : Off
Laser bias current low warning  (Chan 2)  : On
Laser bias current high alarm   (Chan 3)  : Off
Laser bias current low alarm    (Chan 3)  : On
Laser bias current high warning (Chan 3)  : Off
Laser bias current low warning  (Chan 3)  : On
Laser bias current high alarm   (Chan 4)  : Off
Laser bias current low alarm    (Chan 4)  : On
Laser bias current high warning (Chan 4)  : Off
Laser bias current low warning  (Chan 4)  : On
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)   : On
Laser tx power high warning (Channel 1)   : Off
Laser tx power low warning  (Channel 1)   : On
Laser tx power high alarm   (Channel 2)   : Off
Laser tx power low alarm    (Channel 2)   : On
Laser tx power high warning (Channel 2)   : Off
Laser tx power low warning  (Channel 2)   : On
Laser tx power high alarm   (Channel 3)   : Off
Laser tx power low alarm    (Channel 3)   : On
Laser tx power high warning (Channel 3)   : Off
Laser tx power low warning  (Channel 3)   : On
Laser tx power high alarm   (Channel 4)   : On
Laser tx power low alarm    (Channel 4)   : On
Laser tx power high warning (Channel 4)   : On
Laser tx power low warning  (Channel 4)   : On
Laser rx power high alarm   (Channel 1)   : Off
Laser rx power low alarm    (Channel 1)   : On
Laser rx power high warning (Channel 1)   : Off
Laser rx power low warning  (Channel 1)   : On
Laser rx power high alarm   (Channel 2)   : Off
Laser rx power low alarm    (Channel 2)   : On
Laser rx power high warning (Channel 2)   : Off
Laser rx power low warning  (Channel 2)   : On
Laser rx power high alarm   (Channel 3)   : Off
Laser rx power low alarm    (Channel 3)   : On
Laser rx power high warning (Channel 3)   : Off
Laser rx power low warning  (Channel 3)   : On
Laser rx power high alarm   (Channel 4)   : Off
Laser rx power low alarm    (Channel 4)   : On
Laser rx power high warning (Channel 4)   : Off
Laser rx power low warning  (Channel 4)   : On
Laser bias current high alarm threshold   : 55.000 mA
Laser bias current low alarm threshold    : 25.000 mA
Laser bias current high warning threshold : 50.000 mA
Laser bias current low warning threshold  : 30.000 mA
Laser output power high alarm threshold   : 3.5481 mW / 5.50 dBm
Laser output power low alarm threshold    : 0.1585 mW / -8.00 dBm
Laser output power high warning threshold : 1.7783 mW / 2.50 dBm
Laser output power low warning threshold  : 0.3981 mW / -4.00 dBm
Module temperature high alarm threshold   : 60.00 degrees C / 140.00 degrees F
Module temperature low alarm threshold    : 10.00 degrees C / 50.00 degrees F
Module temperature high warning threshold : 55.00 degrees C / 131.00 degrees F
Module temperature low warning threshold  : 15.00 degrees C / 59.00 degrees F
Module voltage high alarm threshold       : 3.6300 V
Module voltage low alarm threshold        : 2.9700 V
Module voltage high warning threshold     : 3.4650 V
Module voltage low warning threshold      : 3.1350 V
Laser rx power high alarm threshold       : 2.2387 mW / 3.50 dBm
Laser rx power low alarm threshold        : 0.0251 mW / -16.00 dBm
Laser rx power high warning threshold     : 1.7783 mW / 2.50 dBm
Laser rx power low warning threshold      : 0.0631 mW / -12.00 dBm

The Vendor OUI 00:90:65 corresponds to 00:90:65 Finisar Corporation

Let's change this to 00:02:C9 Mellanox Technologies, Inc.. After reprogramming:

ethtool -m ens16f1np1

[...]
Vendor name                               : FINISAR CORP.
Vendor OUI                                : 00:02:c9
Vendor PN                                 : FTLC1152RGPL6-FB
[...]

We have changed the Vendor OUI from 00:90:65 Finisar Corporation to 00:02:C9 Mellanox Technologies, Inc., nothing more! (Okay, and of course the checksum...)

Let's check out link again:

ethtool ens16f1np1

Settings for ens16f1np1:
[...]
        Advertised link modes:  40000baseKR4/Full
                                40000baseCR4/Full
                                40000baseSR4/Full
                                40000baseLR4/Full
[...]
        Speed: 40000Mb/s
        Link detected: no (Cable issue, Unsupported cable)

Hooray! We've got a 40Gbit link over 100GBase-CWDM4 transceivers.

For the sake of completeness, full output after reprogramming:

Full ethtool -m ens16f1np1

ethtool -m ens16f1np1

Identifier                                : 0x11 (QSFP28)
Extended identifier                       : 0xcc
Extended identifier description           : 3.5W max. Power consumption
Extended identifier description           : CDR present in TX, CDR present 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 CWDM4 MSA with FEC
Encoding                                  : 0x07 ((256B/257B (transcoded FEC-enabled data))
BR, Nominal                               : 25500Mbps
Rate identifier                           : 0x02
Length (SMF,km)                           : 2km
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                          : 1301.000nm
Laser wavelength tolerance                : 6.500nm
Vendor name                               : FINISAR CORP.
Vendor OUI                                : 00:02:c9
Vendor PN                                 : FTLC1152RGPL6-FB
Vendor rev                                : A0
Vendor SN                                 : UX503M0
Date code                                 : 170131
Revision Compliance                       : SFF-8636 Rev 2.5/2.6/2.7
Module temperature                        : 33.76 degrees C / 92.77 degrees F
Module voltage                            : 3.2505 V
Alarm/warning flags implemented           : Yes
Laser tx bias current (Channel 1)         : 42.068 mA
Laser tx bias current (Channel 2)         : 37.926 mA
Laser tx bias current (Channel 3)         : 38.870 mA
Laser tx bias current (Channel 4)         : 37.968 mA
Transmit avg optical power (Channel 1)    : 1.0778 mW / 0.33 dBm
Transmit avg optical power (Channel 2)    : 1.0394 mW / 0.17 dBm
Transmit avg optical power (Channel 3)    : 0.9198 mW / -0.36 dBm
Transmit avg optical power (Channel 4)    : 1.1533 mW / 0.62 dBm
Rcvr signal avg optical power(Channel 1)  : 0.9969 mW / -0.01 dBm
Rcvr signal avg optical power(Channel 2)  : 0.9100 mW / -0.41 dBm
Rcvr signal avg optical power(Channel 3)  : 0.9101 mW / -0.41 dBm
Rcvr signal avg optical power(Channel 4)  : 0.9713 mW / -0.13 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   : 55.000 mA
Laser bias current low alarm threshold    : 25.000 mA
Laser bias current high warning threshold : 50.000 mA
Laser bias current low warning threshold  : 30.000 mA
Laser output power high alarm threshold   : 3.5481 mW / 5.50 dBm
Laser output power low alarm threshold    : 0.1585 mW / -8.00 dBm
Laser output power high warning threshold : 1.7783 mW / 2.50 dBm
Laser output power low warning threshold  : 0.3981 mW / -4.00 dBm
Module temperature high alarm threshold   : 60.00 degrees C / 140.00 degrees F
Module temperature low alarm threshold    : 10.00 degrees C / 50.00 degrees F
Module temperature high warning threshold : 55.00 degrees C / 131.00 degrees F
Module temperature low warning threshold  : 15.00 degrees C / 59.00 degrees F
Module voltage high alarm threshold       : 3.6300 V
Module voltage low alarm threshold        : 2.9700 V
Module voltage high warning threshold     : 3.4650 V
Module voltage low warning threshold      : 3.1350 V
Laser rx power high alarm threshold       : 2.2387 mW / 3.50 dBm
Laser rx power low alarm threshold        : 0.0251 mW / -16.00 dBm
Laser rx power high warning threshold     : 1.7783 mW / 2.50 dBm
Laser rx power low warning threshold      : 0.0631 mW / -12.00 dBm

Full ethtool ens16f1np1

ethtool ens16f1np1
Settings for ens16f1np1:
        Supported ports: [ FIBRE ]
        Supported link modes:   1000baseKX/Full
                                10000baseKR/Full
                                40000baseKR4/Full
                                40000baseCR4/Full
                                40000baseSR4/Full
                                40000baseLR4/Full
                                25000baseCR/Full
                                25000baseKR/Full
                                25000baseSR/Full
                                50000baseCR2/Full
                                50000baseKR2/Full
                                100000baseKR4/Full
                                100000baseSR4/Full
                                100000baseCR4/Full
                                100000baseLR4_ER4/Full
        Supported pause frame use: Symmetric
        Supports auto-negotiation: Yes
        Supported FEC modes: None        RS      BASER
        Advertised link modes:  40000baseKR4/Full
                                40000baseCR4/Full
                                40000baseSR4/Full
                                40000baseLR4/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: No
        Advertised FEC modes: None       RS      BASER
        Speed: 40000Mb/s
        Duplex: Full
        Auto-negotiation: off
        Port: FIBRE
        PHYAD: 0
        Transceiver: internal
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes