NAME

       ovs-vlan-test - check Linux drivers for problems with vlan traffic

SYNOPSIS

       ovs-vlan-test [-s | --server] control_ip vlan_ip

       Common options:
              [-h | --help] [-V | --version]

DESCRIPTION

       The  ovs-vlan-test  utility  has some limitations, for example, it does not use TCP in its tests. Also it
       does not take into account MTU to detect potential edge cases. To overcome those limitations a  new  tool
       was  developed - ovs-test. ovs-test is currently supported only on Debian so, if possible try to use that
       on instead of ovs-vlan-test.

       The ovs-vlan-test program may be used to check for problems sending 802.1Q traffic which may  occur  when
       running  Open  vSwitch. These problems can occur when Open vSwitch is used to send 802.1Q traffic through
       physical interfaces running certain drivers of certain Linux kernel versions. To run  a  test,  configure
       Open  vSwitch  to  tag traffic originating from vlan_ip and forward it out the target interface. Then run
       the ovs-vlan-test in client mode connecting to an ovs-vlan-test server.  ovs-vlan-test will display  "OK"
       if it did not detect problems.

       Some examples of the types of problems that may be encountered are:

       •      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.

   Client Mode
       An ovs-vlan-test client may be run on a host to check for VLAN connectivity problems.  The client must be
       able  to  establish  HTTP  connections  with  an ovs-vlan-test server located at the specified control_ip
       address.  UDP traffic sourced  at  vlan_ip  should  be  tagged  and  directed  out  the  interface  whose
       connectivity is being tested.

   Server Mode
       To  conduct  tests, an ovs-vlan-test server must be running on a host known not to have VLAN connectivity
       problems.  The server must  have  a  control_ip  on  a  non-VLAN  network  which  clients  can  establish
       connectivity  with.  It must also have a vlan_ip address on a VLAN network which clients will use to test
       their VLAN connectivity.  Multiple clients may test against a single ovs-vlan-test server concurrently.

OPTIONS

       -s
       --server
              Run in server mode.

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

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

EXAMPLES

       Display the Linux kernel version and driver of eth1.

              uname -r

              ethtool -i eth1

       Set up a bridge which forwards traffic originating from 1.2.3.4 out eth1 with VLAN tag 10.

              ovs-vsctl -- add-br vlan-br \

              -- add-port vlan-br eth1 \

              -- add-port vlan-br vlan-br-tag tag=10 \

              -- set Interface vlan-br-tag type=internal

              ifconfig vlan-br-tag up 1.2.3.4

       Run an ovs-vlan-test server listening for client control traffic  on  172.16.0.142  port  8080  and  VLAN
       traffic on the default port of 1.2.3.3.

              ovs-vlan-test -s 172.16.0.142:8080 1.2.3.3

       Run  an  ovs-vlan-test client with a control server located at 172.16.0.142 port 8080 and a local VLAN ip
       of 1.2.3.4.

              ovs-vlan-test 172.16.0.142:8080 1.2.3.4

SEE ALSO

       ovs-vswitchd(8), ovs-ofctl(8), ovs-vsctl(8), ovs-test(8), ethtool(8), uname(1)

Open vSwitch                                          2.0.2                                     ovs-vlan-test(1)