1ovs-vlan-test(1) Open vSwitch Manual ovs-vlan-test(1)
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6 ovs-vlan-test - check Linux drivers for problems with vlan traffic
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9 ovs-vlan-test [-s | --server] control_ip vlan_ip
10 Common options:
12 [-h | --help] [-V | --version]
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16 The ovs-vlan-test utility has some limitations, for example, it does
17 not use TCP in its tests. Also it does not take into account MTU to
18 detect potential edge cases. To overcome those limitations a new tool
19 was developed - ovs-test. ovs-test is currently supported only on
20 Debian so, if possible try to use that on instead of ovs-vlan-test.
21 The ovs-vlan-test program may be used to check for problems sending
23 802.1Q traffic which may occur when running Open vSwitch. These prob‐
24 lems can occur when Open vSwitch is used to send 802.1Q traffic through
25 physical interfaces running certain drivers of certain Linux kernel
26 versions. To run a test, configure Open vSwitch to tag traffic origi‐
27 nating from vlan_ip and forward it out the target interface. Then run
28 the ovs-vlan-test in client mode connecting to an ovs-vlan-test server.
29 ovs-vlan-test will display "OK" if it did not detect problems.
30 Some examples of the types of problems that may be encountered are:
32 · When NICs use VLAN stripping on receive they must pass a pointer
34 to a vlan_group when reporting the stripped tag to the network‐
35 ing core. If no vlan_group is in use then some drivers just
36 drop the extracted tag. Drivers are supposed to only enable
37 stripping if a vlan_group is registered but not all of them do
38 that.
39 · On receive, some drivers handle priority tagged packets spe‐
41 cially and don't pass the tag onto the network stack at all, so
42 Open vSwitch never has a chance to see it.
43 · Some drivers size their receive buffers based on whether a
45 vlan_group is enabled, meaning that a maximum size packet with a
46 VLAN tag will not fit if no vlan_group is configured.
47 · On transmit, some drivers expect that VLAN acceleration will be
49 used if it is available, which can only be done if a vlan_group
50 is configured. In these cases, the driver may fail to parse the
51 packet and correctly setup checksum offloading or TSO.
52 Client Mode
54 An ovs-vlan-test client may be run on a host to check for VLAN connec‐
55 tivity problems. The client must be able to establish HTTP connections
56 with an ovs-vlan-test server located at the specified control_ip
57 address. UDP traffic sourced at vlan_ip should be tagged and directed
58 out the interface whose connectivity is being tested.
59 Server Mode
61 To conduct tests, an ovs-vlan-test server must be running on a host
62 known not to have VLAN connectivity problems. The server must have a
63 control_ip on a non-VLAN network which clients can establish connectiv‐
64 ity with. It must also have a vlan_ip address on a VLAN network which
65 clients will use to test their VLAN connectivity. Multiple clients may
66 test against a single ovs-vlan-test server concurrently.
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69 -s
70 --server
71 Run in server mode.
72 -h
74 --help Prints a brief help message to the console.
75 -V
77 --version
78 Prints version information to the console.
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81 Display the Linux kernel version and driver of eth1.
82 uname -r
84 ethtool -i eth1
86 Set up a bridge which forwards traffic originating from 1.2.3.4 out
88 eth1 with VLAN tag 10.
89 ovs-vsctl -- add-br vlan-br \
91 -- add-port vlan-br eth1 \
93 -- add-port vlan-br vlan-br-tag tag=10 \
95 -- set Interface vlan-br-tag type=internal
97 ifconfig vlan-br-tag up 1.2.3.4
99 Run an ovs-vlan-test server listening for client control traffic on
101 172.16.0.142 port 8080 and VLAN traffic on the default port of 1.2.3.3.
102 ovs-vlan-test -s 172.16.0.142:8080 1.2.3.3
104 Run an ovs-vlan-test client with a control server located at
106 172.16.0.142 port 8080 and a local VLAN ip of 1.2.3.4.
107 ovs-vlan-test 172.16.0.142:8080 1.2.3.4
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111 ovs-vswitchd(8), ovs-ofctl(8), ovs-vsctl(8), ovs-test(8), ethtool(8),
112 uname(1)
113Open vSwitch 2.0.0 ovs-vlan-test(1)