+ questions. You can also suggest improvements to documentation. If
+ you have a feature or bug you would like to work on, send a mail to
+ one of the mailing lists:
+
+ http://openvswitch.org/mlists/
+
+
+
+Releases
+--------
+
+Q: What does it mean for an Open vSwitch release to be LTS (long-term
+ support)?
+
+A: All official releases have been through a comprehensive testing
+ process and are suitable for production use. Planned releases will
+ occur several times a year. If a significant bug is identified in an
+ LTS release, we will provide an updated release that includes the
+ fix. Releases that are not LTS may not be fixed and may just be
+ supplanted by the next major release. The current LTS release is
+ 1.4.x.
+
+Q: What features are not available in the Open vSwitch kernel datapath
+ that ships as part of the upstream Linux kernel?
+
+A: The kernel module in upstream Linux 3.3 and later does not include
+ the following features:
+
+ - Bridge compatibility, that is, support for the ovs-brcompatd
+ daemon that (if you enable it) lets "brctl" and other Linux
+ bridge tools transparently work with Open vSwitch instead.
+
+ We do not expect bridge compatibility to ever be available in
+ upstream Linux. If you need bridge compatibility, use the
+ kernel module from the Open vSwitch distribution instead of the
+ upstream Linux kernel module.
+
+ - Tunnel virtual ports, that is, interfaces with type "gre",
+ "ipsec_gre", "capwap". It is possible to create tunnels in
+ Linux and attach them to Open vSwitch as system devices.
+ However, they cannot be dynamically created through the OVSDB
+ protocol or set the tunnel ids as a flow action.
+
+ Work is in progress in adding these features to the upstream
+ Linux version of the Open vSwitch kernel module. For now, if
+ you need these features, use the kernel module from the Open
+ vSwitch distribution instead of the upstream Linux kernel
+ module.
+
+ - Patch virtual ports, that is, interfaces with type "patch".
+ You can use Linux "veth" devices as a substitute.
+
+ We don't have any plans to add patch ports upstream.
+
+Q: What features are not available when using the userspace datapath?
+
+A: Tunnel and patch virtual ports are not supported, as described in the
+ previous answer. It is also not possible to use queue-related
+ actions. On Linux kernels before 2.6.39, maximum-sized VLAN packets
+ may not be transmitted.
+
+
+Terminology
+-----------
+
+Q: I thought Open vSwitch was a virtual Ethernet switch, but the
+ documentation keeps talking about bridges. What's a bridge?
+
+A: In networking, the terms "bridge" and "switch" are synonyms. Open
+ vSwitch implements an Ethernet switch, which means that it is also
+ an Ethernet bridge.
+
+Q: What's a VLAN?
+
+A: See the "VLAN" section below.
+
+
+Basic Configuration
+-------------------
+
+Q: How do I configure a port as an access port?
+
+A: Add "tag=VLAN" to your "ovs-vsctl add-port" command. For example,
+ the following commands configure br0 with eth0 as a trunk port (the
+ default) and tap0 as an access port for VLAN 9:
+
+ ovs-vsctl add-br br0
+ ovs-vsctl add-port br0 eth0
+ ovs-vsctl add-port br0 tap0 tag=9
+
+ If you want to configure an already added port as an access port,
+ use "ovs-vsctl set", e.g.:
+
+ ovs-vsctl set port tap0 tag=9
+
+Q: How do I configure a port as a SPAN port, that is, enable mirroring
+ of all traffic to that port?
+
+A: The following commands configure br0 with eth0 and tap0 as trunk
+ ports. All traffic coming in or going out on eth0 or tap0 is also
+ mirrored to tap1; any traffic arriving on tap1 is dropped:
+
+ ovs-vsctl add-br br0
+ ovs-vsctl add-port br0 eth0
+ ovs-vsctl add-port br0 tap0
+ ovs-vsctl add-port br0 tap1 \
+ -- --id=@p get port tap1 \
+ -- --id=@m create mirror name=m0 select-all=true output-port=@p \
+ -- set bridge br0 mirrors=@m
+
+ To later disable mirroring, run:
+
+ ovs-vsctl clear bridge br0 mirrors
+
+Q: How do I configure a VLAN as an RSPAN VLAN, that is, enable
+ mirroring of all traffic to that VLAN?
+
+A: The following commands configure br0 with eth0 as a trunk port and
+ tap0 as an access port for VLAN 10. All traffic coming in or going
+ out on tap0, as well as traffic coming in or going out on eth0 in
+ VLAN 10, is also mirrored to VLAN 15 on eth0. The original tag for
+ VLAN 10, in cases where one is present, is dropped as part of
+ mirroring:
+
+ ovs-vsctl add-br br0
+ ovs-vsctl add-port br0 eth0
+ ovs-vsctl add-port br0 tap0 tag=10
+ ovs-vsctl \
+ -- --id=@m create mirror name=m0 select-all=true select-vlan=10 \
+ output-vlan=15 \
+ -- set bridge br0 mirrors=@m
+
+ To later disable mirroring, run:
+
+ ovs-vsctl clear bridge br0 mirrors