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Unable to Bring up Copper SFP on Dell S4048-ON



I am unable to bring up link with a copper SFP on a Dell S4048-ON switch. The following message appears in /var/log/syslog:

portwd: MV88E1111 with revision 1 silicon detected in port swp45. Disabling port.

ip link show indicates the port is admin down after bringing it up:

cumulus@switch$ sudo ip link set swp45 up
cumulus@switch$ ip link show swp45
47: swp45: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 500 
    link/ether cc:37:ab:2c:9a:b1 brd ff:ff:ff:ff:ff:ff


  • Dell S4048-ON
  • Copper SFP
  • Cumulus Linux versions after 2.5.3


Use an alternate SFP with a later revision of RJ45 module silicon.

Root Cause

Copper SFPs with Marvell revision 1 RJ45 module silicon [1] have been found to lock up the bus on the Dell S4048-ON. The portwd daemon therefore shuts down SFPs with this revision to discourage use. This behavior is not configurable.

The following is an incomplete list of SFPs previously observed to be affected by this issue.  This list will be updated as additional SFPs are confirmed to be affected.

VendorPart NumberRevision
Arista Networks SFP-1G-T 0002
Methode Elec. SP7041-M1-JN -


Diagnostic Steps

You can run the attached script against a particular port on a Dell S4048-ON to check the RJ45 module revision:

cumulus@switch$ sudo python swp32

c10c is the affected revision 1 silicon. c20c and later revisions are not affected.


  • Avatar
    Mike Brown

    Here are a few more modules that were found with a MV88E1111 revision 1 silicon. Since this Vendor data can be overwritten by any manufacturer or distributor, the script above is the way to get the final word on the hardware revision of a 1G Copper SFP.

    # ethtool -m swp37 | grep Vend
    Vendor name : CISCO-AVAGO
    Vendor OUI : 00:17:6a
    Vendor PN : ABCU-5710RZ-CS2
    Vendor rev : 02
    # ethtool -m swp38 | grep Vend
    Vendor name : Methode Elec.
    Vendor OUI : 00:00:00
    Vendor PN : SP7041-M1-JN
    Vendor rev : -
    # ethtool -m swp39 | grep Vend
    Vendor name : Arista Networks
    Vendor OUI : 00:1c:73
    Vendor PN : SFP-1G-T
    Vendor rev : 0002
    # ethtool -m swp2 | grep Vend
    Vendor name : CISCO-EQUIV
    Vendor OUI : 00:00:00
    Vendor PN : GLC-T-ENC
    Vendor rev : A

  • Avatar
    Trap Marshall

    Thanks Mike! Added those to the table.

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