ovs-vlan-bug-workaround(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | DRIVER DETAILS | OPTIONS | BUGS | SEE ALSO | COLOPHON

ovs-vlan-bug-workaround(8) Open vSwitch Manualovs-vlan-bug-workaround(8)

NAME         top

       ovs-vlan-bug-workaround - utility for configuring Linux VLAN
       driver bug workaround

SYNOPSIS         top

       ovs-vlan-bug-workaround netdev on
       ovs-vlan-bug-workaround netdev off
       ovs-vlan-bug-workaround --help
       ovs-vlan-bug-workaround --version

DESCRIPTION         top

       Some Linux network drivers support a feature called ``VLAN
       acceleration''.  VLAN acceleration is associated with a data
       structure called a vlan_group that is, abstractly, a dictionary
       that maps from a VLAN ID (in the range 0 to 4095) to a VLAN
       device, that is, a Linux network device associated with a
       particular VLAN, e.g. eth0.9 for VLAN 9 on eth0.

       Some drivers that support VLAN acceleration have bugs that fall
       roughly into the categories listed below.  ovs-vlan-test(8) can
       test for these driver bugs.

       •      When NICs use VLAN stripping on receive they must pass a
              pointer to a vlan_group when reporting the stripped tag to
              the networking core.  If no vlan_group is in use then some
              drivers just drop the extracted tag.  Drivers are supposed
              to only enable stripping if a vlan_group is registered but
              not all of them do that.

       •      On receive, some drivers handle priority tagged packets
              specially and don't pass the tag onto the network stack at
              all, so Open vSwitch never has a chance to see it.

       •      Some drivers size their receive buffers based on whether a
              vlan_group is enabled, meaning that a maximum size packet
              with a VLAN tag will not fit if no vlan_group is
              configured.

       •      On transmit, some drivers expect that VLAN acceleration
              will be used if it is available, which can only be done if
              a vlan_group is configured.  In these cases, the driver
              may fail to parse the packet and correctly setup checksum
              offloading or TSO.

       The correct long term solution is to fix these driver bugs.

       For now, ovs-vlan-bug-workaround can enable a special-purpose
       workaround for devices with buggy VLAN acceleration.  A kernel
       patch must be applied for this workaround to work.

       Use the command ovs-vlan-bug-workaround netdev on to enable the
       VLAN driver bug workaround for network device netdev.  Use the
       command ovs-vlan-bug-workaround netdev off to disable the VLAN
       driver bug workaround for network device netdev.

DRIVER DETAILS         top

       The following drivers in Linux version
       2.6.32.12-0.7.1.xs1.0.0.311.170586 implement VLAN acceleration
       and are relevant to Open vSwitch on XenServer.  We have not
       tested any version of most of these drivers, so we do not know
       whether they have a VLAN problem that needs to be fixed.  The
       drivers are listed by the name that they report in, e.g., ethtool
       -i output; in a few cases this differs slightly from the name of
       the module's .ko file:
       8139cp    acenic    amd8111e  atl1c     ATL1E     atl1
       atl2      be2net    bna       bnx2      bnx2x     cnic
       cxgb      cxgb3     e1000     e1000e    enic      forcedeth
       igb       igbvf     ixgb      ixgbe     jme       ml4x_core
       ns83820   qlge      r8169     S2IO      sky2      starfire
       tehuti    tg3       typhoon   via-velocity        vxge

       The following drivers use vlan_group but are irrelevant to Open
       vSwitch on XenServer:

       bonding
              Not used with Open vSwitch on XenServer.

       gianfar
              Not shipped with XenServer.  A FreeScale CPU-integrated
              device.

       ehea   Cannot be built on x86.  IBM Power architecture only.

       stmmac Cannot be built on x86.  SH4 architecture only.

       vmxnet3
              Not shipped with XenServer.  For use inside VMware VMs
              only.

OPTIONS         top

       -h
       --help Prints a brief help message to the console.

       -V
       --version
              Prints version information to the console.

BUGS         top

       Obviously.

SEE ALSO         top

       ovs-vlan-test(8).

COLOPHON         top

       This page is part of the Open vSwitch (a distributed virtual
       multilayer switch) project.  Information about the project can be
       found at ⟨http://openvswitch.org/⟩.  If you have a bug report for
       this manual page, send it to bugs@openvswitch.org.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/openvswitch/ovs.git⟩ on 2021-08-27.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-08-20.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

Open vSwitch                     2.11.90      ovs-vlan-bug-workaround(8)