What SFP+ Modules does the 10Gbps or 25gbps card support   |   fiber adapter not online


What SFP+ Modules does the 10Gbps and 25Gbps card support   |   Intel-x520 10Gbe adapter not online


You are trying to connect SFP or SFP+ adapter card in a Unitrends Physical appliance and the link state is not establishing.  

Note, this article applies only if you have purchased the Unitrends 2x10G SFP+ card in Generation 7, 8, or 9 appliance, or a Unitrends 2x25Gbps SFP28 adapter installed in a Generation 10 appliance.  Note 10G SFP cards are not supported in Gen10 units and SFP28 cards are not supported in older models. 

You must have the correct SFP+ or SFP28 Optical Module (transceiver) installed of the correct brand in order to ensure the Unitrends system can communicate with the Switch hardware.   Unitrends does not supply or sell these transceivers.  Please contact your reseller or 3rd party about how to acquire the parts noted below.  

A Note about Speeds and adapter types.  When the modules at each end of the cable differ, the lower speed supported will be leveraged, but not all modules support all speeds.  

  • SFP modules run at only 100mbit or 1gbit speeds
  • SFP+ modules run at only 1gbit or 10gbit speeds
  • SFP28 modules run at only 10gbit or 25gbit speeds.  

  • SFP ports only accept SFP modules
  • SFP+ ports can accept SFP+ and SFP modules
  • SFP28 ports can accept SFP28 or SFP+ modules, but not SFP modules.  

Given these limitations, an SFP28 module cannot be used to communicate to an SFP switch, only to an SFP+ switch when configured with an SFP28 module.  If your switches have only SFP, not SFP+, and you acquire an SFP28 adapter, you must install SFP+ modules and will further be limited to a max 1gbit speed using that adapter.  If your switch is SFP+ capable, Unitrends recommends upgrading to SFP+ modules when pairing with Gen 10 appliances, or, replace your switches with 10g or 25G capable FSP+, SFP28, or copper 10G rj45.  

Possible connection types supported:

Unlike SFP which requires supported SFP transceivers on both ends, SFP+, and SFP28 support a variety of connection types.  The common popular type is using SFP+ transceivers and fiber cabling.  However, if the adapter in the Unitrends appliance AND your switch BOTH support SFP+ or SFP28 (not just classic SFP, but SFP+ or better), then you may be able to use any of the below configurations.  

  • SFP+ to SFP+ at 10gbit using fiber cabling for 300m or 10km
  • SFP+ to SFP at 1gbit using fiber cabling for 300m or 10km
  • SFP28 to SFP28 at 25gbit using fiber cabling for 100m or 10km
  • SFP28 to SFP+ at 10gbit using fiber cabling for 100m or 10km
  • SFP+-to-Copper RJ45 connection at 10gbit up to 100m (using Cat 6A, 55m with Can 6)
  • Passive SFP+ DAC (Direct Attached Cabling) at 10gbit aka Twinax SFP+ cabling up to 7m
  • Active SFP+ DAC (Direct Attached Cabling) aka Twinax SFP+ cabling up to 15m
  • Passive SFP28 DAC (Direct Attached Cabling) at 25gbit aka Twinax SFP28 cabling up to 5m
  • AOC (Active Optic Cables) SFP+ at 10gbit up to 100m
  • AOC  (Active Optic Cables) SFP28 at 25gbit up to 100m

SFP+/SFP28 transceivers:

According to the Intel Ethernet SFP+ Optics Brief (clicking this link will download a PDF), the following two Optical Transceiver Modules are acceptable in the 10G card SFP ports used in the generation 7, 8, or 9 Unitrends appliances equipped with the 2 port 10G SFP+ adapter.  only thse exact models will be supported.  These transceivers can communicate to any SFP or SFP+ transceivers in your switch that is supported by your switch vendor:

  • E10GSFPSR – Intel® Ethernet SFP+ SR Optic (850nm, OM4 Short Range 300m)
  • E10GSFPLR – Intel® Ethernet SFP+ LR Optic (1310nm, OS2 Long Range 10km)
    NOTE: the wavelength is VERY important

According to the Intel Ethernet SFP28 Optics Brief (Clicking this link will download a PDF) the following 2 optics are compatible with intel SFP28 25gbit cards used in Unitrends Generation 10 appliances.  Note, SFP28 cards ALSO accept the SFP+ transceivers above, but the card above will not accept SFP28 transceivers.  These transceivers can communicate to any SFP28 or SFP+ transceiver but will only run at 10G on SFP+ compatibility mode.  

  • E25GSFP28SR - Intel® Ethernet SFP28 SR Optic (850nm, OM4 Short Range 100m)
  • E25GSFP28LRX - Intel® Ethernet SFP28 LR Optic (1310nm, OS2 Long Range 10km)

SFP+ to RJ45 Connection: for customers without SFP-type switching equipment in their environment who require traditional RJ45 copper cabling, the following adapter converts SFP+ or SFP28 to RJ45 copper for use with standard 10G or 25G copper switch ports and has been tested by Unitrends QA teams:

   10Gtek Intel Compatible 10GBase-T SFP+ 10 Gigabit RJ45 Copper Transceiver 30-Meter

NOTE about Brand Compatibility The above denotes the SFP+/SFP28 module required at the Unitrends end of your fiber run and the fiber cable type requirement.  At the other end of the cable, you will typically use an alternate vendor adapter that is compatible with your switch. As an example on our end of the cable you would use an Intel SFP above but at the other end you may need a Cisco SFP+.  The transceiver on both ends rarely is the same model. 

SFP DAC or AOC Cabling: 
In contrast, Any brand of copper SFP+ Direct Attached Cables (DAC) will work when SFP+ switch/card ports are supported on both ends of the cable.  SFP28 DAC cabling can be used when both sides support SFP28 modules.  DAC, also commonly called Twinax cabling, eliminates the need for vendor-specific transceivers when cable lengths of 5-15m are acceptable.  AOC cabling uses pre-fused fiber cables and generic transceivers and can be a popular option that may save costs vs cutting specific fiber lengths for short cable runs.  

Twinax or DAC cabling is vendor-independent and any SFP+ or SFP28 cable should work when both sized of the cable support the same topology.  Twinax cabling however will NOT work with classic SFP, it requires SFP+.  (SFP28 is backward compatible with SFP+).

Though Intel supports AOC cabling with the adapters used by unitrends, Unitrends has not specifically tested them in our QA processes so we cannot guarantee their function, though per the cabling and card specs for SFP they are expected to function. 


The remainder of this article discusses how to troubleshoot SFP connectivity issues for the 10/25G Adapter assuming you have the correct SFP+/SFP28 adapters or supported cabling installed on both ends of your connection.  



Unitrends provided SFP card is not coming online or showing a link, but is seen by the RecoveryOS.



You can use the ethtool to determine if the card is identified and connected using the command  

ethtool <interface>

The interface value is what you would find identified using the command ifconfig.

[root@UB_BETA_91 ~]# ifconfig
eth5      Link encap:Ethernet  HWaddr 00:0f:99:04:63:C9
          inet addr:  Bcast:  Mask:

Successful results will look something like this (see red items) showing the results of yes for Link Connected, and the properties of Speed, Duplex, and Port:

[root@UB_BETA_91 ~]# ethtool eth5
Settings for eth5:
        Supported ports: [ TP ]
        Supported link modes:   1000baseT/Full
        Supported pause frame use: No
        Supports auto-negotiation: No
        Advertised link modes:  Not reported
        Advertised pause frame use: No
        Advertised auto-negotiation: No
        Speed: 10000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: off
        MDI-X: Unknown
        Supports Wake-on: uag
        Wake-on: d
        Link detected: yes

If you are using the noted correct adapters, and you are not acquiring a link state, please contact your switch vendor directly for further support.  Unitrends Staff cannot assist in switch-side diagnostics of connectivity but will be happy to engage with you and your vendor to assist in testing our end of the connection further under their guidance. 

Unlike copper RJ45, most 10G and faster switches require specific and manual port provisioning for SFP fiber connections and they are not simply plug-and-play.  Only your switch vendor or a certified network engineer trained in your switch vendor's OS can assist you if the connection is not properly detected by Linux on the Unitrends Appliance.  


When using any SFP module other than the specific intel brands noted above the SFP module will not function.   When installing SFP fiber modules, it is important that the SFP module on each end be specific to the switch and/or card used.  It is commonly NOT expected that the same SFP module be used on both ends of the connection, in fact, typically they will be different. 




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