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NAME | SYNOPSIS | DESCRIPTION | DRIVER DETAILS | OPTIONS | BUGS | SEE ALSO | COLOPHON |
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ovs-vlan-bug-workaround(8) Open vSwitch Manual ovs-vlan-bug-workaround(8)
ovs-vlan-bug-workaround - utility for configuring Linux VLAN driver
bug workaround
ovs-vlan-bug-workaround netdev on
ovs-vlan-bug-workaround netdev off
ovs-vlan-bug-workaround --help
ovs-vlan-bug-workaround --version
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.
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.
-h
--help Prints a brief help message to the console.
-V
--version
Prints version information to the console.
Obviously.
ovs-vlan-test(8).
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 2018-02-02. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2018-02-01.) 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 2.8.90 ovs-vlan-bug-workaround(8)
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