FAQ: Add additional entries.

Does some cleanup and adds entries that cover:

    - OVS isn't Linux-specific.
    - Point out PORTING guide.
    - Explanation of LTS releases.
    - Supported versions of OpenFlow.
    - Missing features from userspace datapath and upstream kernel
      module.

Signed-off-by: Justin Pettit <jpettit@nicira.com>

diff --git a/FAQ b/FAQ
index 18ecc913167a6ba3f7385f0929a6fc3b77e6e7d1..3cd1fa353695799e8cc4f6160db63937685f4a74 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -35,23 +35,42 @@ A: Open vSwitch can currently run on any Linux-based virtualization
 
 Q: How can I try Open vSwitch?
 
 
 Q: How can I try Open vSwitch?
 

-A: Open vSwitch is as source code to be built on a Linux system.  You
-   can build and experiment with Open vSwitch on any Linux machine.
-   Packages for various Linux distributions are underway and will be linked
-   to from this website as they materialize.
+A: The Open vSwitch source code can be built on a Linux system.  You can
+   build and experiment with Open vSwitch on any Linux machine.
+   Packages for various Linux distributions are available on many
+   platforms, including: Debian, Ubuntu, Fedora.

 
    You may also download and run a virtualization platform that already
 
    You may also download and run a virtualization platform that already

-   has Open vSwitch integrated.  For example, download the ISO for Xen
-   Cloud Platform.  Be aware that the version integrated with a
-   particular platform may not be the most recent Open vSwitch release.
+   has Open vSwitch integrated.  For example, download a recent ISO for
+   XenServer or Xen Cloud Platform.  Be aware that the version
+   integrated with a particular platform may not be the most recent Open
+   vSwitch release.
+
+Q: Does Open vSwitch only work on Linux?
+
+A: No, Open vSwitch has been ported to a number of different operating
+   systems and hardware platforms.  Most of the development work occurs
+   on Linux, but the code should be portable to any POSIX system.  We've
+   seen Open vSwitch ported to a number of different platforms,
+   including FreeBSD, Windows, and even non-POSIX embedded systems.
+
+   By definition, the Open vSwitch Linux kernel module only works on
+   Linux and will provide the highest performance.  However, a userspace
+   datapath is available that should be very portable.
+
+Q: What's involved with porting Open vSwitch to a new platform or
+   switching ASIC?
+
+A: The PORTING document describes how one would go about porting Open
+   vSwitch to a new operating system or hardware platform.

 
 Q: Why would I use Open vSwitch instead of the Linux bridge?
 
 A: Open vSwitch is specially designed to make it easier to manage VM
 
 Q: Why would I use Open vSwitch instead of the Linux bridge?
 
 A: Open vSwitch is specially designed to make it easier to manage VM

-   network configuration and monitoring state spread across many
-   physical hosts in dynamic virtualized environments.  Please see
-   WHY-OVS for a more detailed description of how Open vSwitch relates
-   to the Linux Bridge.
+   network configuration and monitor state spread across many physical
+   hosts in dynamic virtualized environments.  Please see WHY-OVS for a
+   more detailed description of how Open vSwitch relates to the Linux
+   Bridge.

 
 Q: How is Open vSwitch related to distributed virtual switches like the
    VMware vNetwork distributed switch or the Cisco Nexus 1000V?
 
 Q: How is Open vSwitch related to distributed virtual switches like the
    VMware vNetwork distributed switch or the Cisco Nexus 1000V?


@@ -84,24 +103,65 @@ A: Open vSwitch is intended to be a useful component for building
    support all as a primitive building block rather than choose a
    particular point in the distributed design space.
 
    support all as a primitive building block rather than choose a
    particular point in the distributed design space.
 

-Q: What does it mean for an Open vSwitch release to be "stable"?
-
-A: A stable Open vSwitch release is code that has been through a
-   comprehensive testing process and is suitable for production use.
-   Planned stable releases will occur several times a year.  If a
-   significant bug is identified in a stable release, we will provide an
-   updated stable release that includes the fix.  Developers looking to
-   test the latest Open vSwitch code can use an "unstable" release or
-   directly access the code via git.
-

 Q: How can I contribute to the Open vSwitch Community?
 
 A: You can start by joining the mailing lists and helping to answer
 Q: How can I contribute to the Open vSwitch Community?
 
 A: You can start by joining the mailing lists and helping to answer

-   questions.  You can also suggest improvements to documentation or offer
-   to write a configuration cookbook entry.
+   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)?

 
 

-   If you have a feature or bug you would like to work on send a mail to
-   dev mailing list.
+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 and patch virtual ports, that is, interfaces with type
+         "gre", "ipsec_gre", "capwap", or "patch".  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.
+
+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.

 
 
 Configuration Problems
 
 
 Configuration Problems


@@ -251,7 +311,7 @@ A: Many drivers in Linux kernels before version 3.3 had VLAN-related
          that works around bugs in kernel drivers.  To enable VLAN
          splinters on interface eth0, use the command:
 
          that works around bugs in kernel drivers.  To enable VLAN
          splinters on interface eth0, use the command:
 

-             ovs-vsctl set interface eth0 other-config:enable-vlan-splinters=true
+           ovs-vsctl set interface eth0 other-config:enable-vlan-splinters=true

 
          For VLAN splinters to be effective, Open vSwitch must know
          which VLANs are in use.  See the "VLAN splinters" section in
 
          For VLAN splinters to be effective, Open vSwitch must know
          which VLANs are in use.  See the "VLAN splinters" section in


@@ -344,6 +404,15 @@ A: The configuration for VLANs in the Open vSwitch database (e.g. via
 Controllers
 -----------
 
 Controllers
 -----------
 

+Q: What versions of OpenFlow does Open vSwitch support?
+
+A: Open vSwitch supports OpenFlow 1.0.  It also includes a number of
+   extensions that bring many of the features from later versions of
+   OpenFlow.  Work is underway to provide support for later versions and
+   can be tracked here:
+
+       http://openvswitch.org/development/openflow-1-x-plan/
+

 Q: I'm getting "error type 45250 code 0".  What's that?
 
 A: This is a Open vSwitch extension to OpenFlow error codes.  Open
 Q: I'm getting "error type 45250 code 0".  What's that?
 
 A: This is a Open vSwitch extension to OpenFlow error codes.  Open


@@ -416,6 +485,7 @@ Q: My OpenFlow controller doesn't see the VLANs that I expect.
 
 A: See answer under "VLANs", above.
 
 
 A: See answer under "VLANs", above.
 

+

 Contact 
 -------
 
 Contact 
 -------