ovs-vlan-test(8)

1OVS-VLAN-TEST(8)                 Open vSwitch                 OVS-VLAN-TEST(8)
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NAME

6       ovs-vlan-test - Check Linux drivers for problems with vlan traffic
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SYNOPSIS

9       ovs-vlan-test [-s | –server] control_ip vlan_ip
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DESCRIPTION

12       The  ovs-vlan-test  utility  has some limitations, for example, it does
13       not use TCP in its tests. Also it does not take into account MTU to de‐
14       tect potential edge cases. To overcome those limitations a new tool was
15       developed - ovs-test. ovs-test is currently supported  only  on  Debian
16       so, if possible, try to use that on instead of ovs-vlan-test.
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18       The  ovs-vlan-test  program  may  be used to check for problems sending
19       802.1Q traffic which may occur when running Open vSwitch.  These  prob‐
20       lems can occur when Open vSwitch is used to send 802.1Q traffic through
21       physical interfaces running certain drivers  of  certain  Linux  kernel
22       versions.  To  run a test, configure Open vSwitch to tag traffic origi‐
23       nating from vlan_ip and forward it out the target interface.  Then  run
24       the ovs-vlan-test in client mode connecting to an ovs-vlan-test server.
25       ovs-vlan-test will display “OK” if it did not detect problems.
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27       Some examples of the types of problems that may be encountered are:
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29       • When NICs use VLAN stripping on receive they must pass a pointer to a
30         vlan_group when reporting the stripped tag to the networking core. If
31         no vlan_group is in use then some drivers  just  drop  the  extracted
32         tag.   Drivers  are supposed to only enable stripping if a vlan_group
33         is registered but not all of them do that.
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35       • On receive, some drivers handle priority tagged packets specially and
36         don’t  pass  the  tag  onto the network stack at all, so Open vSwitch
37         never has a chance to see it.
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39       • Some drivers size their receive buffers based on whether a vlan_group
40         is  enabled,  meaning that a maximum size packet with a VLAN tag will
41         not fit if no vlan_group is configured.
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43       • On transmit, some drivers expect that VLAN acceleration will be  used
44         if it is available, which can only be done if a vlan_group is config‐
45         ured. In these cases, the driver may fail to  parse  the  packet  and
46         correctly setup checksum offloading or TSO.
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48       Client Mode
49              An  ovs-vlan-test  client may be run on a host to check for VLAN
50              connectivity problems. The client must be able to establish HTTP
51              connections  with  an ovs-vlan-test server located at the speci‐
52              fied control_ip address. UDP traffic sourced at  vlan_ip  should
53              be  tagged  and directed out the interface whose connectivity is
54              being tested.
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56       Server Mode
57              To conduct tests, an ovs-vlan-test server must be running  on  a
58              host  known  not  to have VLAN connectivity problems. The server
59              must have a control_ip on a non-VLAN network which  clients  can
60              establish connectivity with. It must also have a vlan_ip address
61              on a VLAN network which clients will use to test their VLAN con‐
62              nectivity.   Multiple   clients   may   test  against  a  single
63              ovs-vlan-test server concurrently.
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OPTIONS

66       -s, --server
67              Run in server mode.
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69       -h, --help
70              Prints a brief help message to the console.
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72       -V, --version
73              Prints version information to the console.
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EXAMPLES

76       Display the Linux kernel version and driver of eth1:
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78          uname -r
79          ethtool -i eth1
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81       Set up a bridge which forwards traffic  originating  from  1.2.3.4  out
82       eth1 with VLAN tag 10:
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84          ovs-vsctl -- add-br vlan-br \
85            -- add-port vlan-br eth1 \
86            -- add-port vlan-br vlan-br-tag tag=10 \
87            -- set Interface vlan-br-tag type=internal
88          ip addr add 1.2.3.4/8 dev vlan-br-tag
89          ip link set vlan-br-tag up
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91       Run  an  ovs-vlan-test  server  listening for client control traffic on
92       172.16.0.142 port 8080 and VLAN traffic on the default port of 1.2.3.3:
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94          ovs-vlan-test -s 172.16.0.142:8080 1.2.3.3
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96       Run  an  ovs-vlan-test  client  with  a  control  server   located   at
97       172.16.0.142 port 8080 and a local VLAN IP of 1.2.3.4:
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99          ovs-vlan-test 172.16.0.142:8080 1.2.3.4
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AUTHOR

106       The Open vSwitch Development Community
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COPYRIGHT

109       2016-2023, The Open vSwitch Development Community
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1143.1                              Jun 08, 2023                 OVS-VLAN-TEST(8)