|
NAME | SYNOPSIS | DESCRIPTION | DRIVER DETAILS | OPTIONS | BUGS | SEE ALSO | COLOPHON |
|
|
|
ovs-vlan-bug-workaround(8) Open vSwitch Manualovs-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 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)
|
HTML rendering created 2021-08-27 by Michael Kerrisk, author of The Linux Programming Interface, maintainer of the Linux man-pages project. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|