ovs-controller: Rename test-controller and do not install or package.

[sliver-openvswitch.git] / FAQ

diff --git a/FAQ b/FAQ
index d36495c..cd3241a 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -89,10 +89,9 @@ A: Distributed vswitch applications (e.g., VMware vNetwork distributed
    environments: OpenFlow, which exposes flow-based forwarding state,
    and the OVSDB management protocol, which exposes switch port state.
    In addition to the switch implementation itself, Open vSwitch
-   includes tools (ovs-controller, ovs-ofctl, ovs-vsctl) that developers
-   can script and extend to provide distributed vswitch capabilities
-   that are closely integrated with their virtualization management
-   platform.
+   includes tools (ovs-ofctl, ovs-vsctl) that developers can script and
+   extend to provide distributed vswitch capabilities that are closely
+   integrated with their virtualization management platform.
 
 Q: Why doesn't Open vSwitch support distribution?
 
@@ -149,6 +148,7 @@ A: The following table lists the Linux kernel versions against which the
        1.10.x     2.6.18 to 3.8
        1.11.x     2.6.18 to 3.8
        2.0.x      2.6.32 to 3.10
+       2.1.x      2.6.32 to 3.11
 
    Open vSwitch userspace should also work with the Linux kernel module
    built into Linux 3.3 and later.
@@ -168,7 +168,7 @@ Q: Should userspace or kernel be upgraded first to minimize downtime?
    kernel version included in the same release or with the version
    from upstream Linux.  However, when upgrading between two releases
    of Open vSwitch it is best to migrate userspace first to reduce
-   the possbility of incompatibilities.
+   the possibility of incompatibilities.
 
 Q: What features are not available in the Open vSwitch kernel datapath
    that ships as part of the upstream Linux kernel?
@@ -197,6 +197,25 @@ A: Tunnel virtual ports are not supported, as described in the
    actions.  On Linux kernels before 2.6.39, maximum-sized VLAN packets
    may not be transmitted.
 
+Q: What happened to the bridge compatibility feature?
+
+A: Bridge compatibility was a feature of Open vSwitch 1.9 and earlier.
+   When it was enabled, Open vSwitch imitated the interface of the
+   Linux kernel "bridge" module.  This allowed users to drop Open
+   vSwitch into environments designed to use the Linux kernel bridge
+   module without adapting the environment to use Open vSwitch.
+
+   Open vSwitch 1.10 and later do not support bridge compatibility.
+   The feature was dropped because version 1.10 adopted a new internal
+   architecture that made bridge compatibility difficult to maintain.
+   Now that many environments use OVS directly, it would be rarely
+   useful in any case.
+
+   To use bridge compatibility, install OVS 1.9 or earlier, including
+   the accompanying kernel modules (both the main and bridge
+   compatibility modules), following the instructions that come with
+   the release.  Be sure to start the ovs-brcompatd daemon.
+
 
 Terminology
 -----------
@@ -1235,9 +1254,11 @@ A: To debug network behavior problems, trace the path of a packet,
 
 Q: How do I make a flow drop packets?
 
-A: An empty set of actions causes a packet to be dropped.  You can
-   specify an empty set of actions with "actions=" on the ovs-ofctl
-   command line.  For example:
+A: To drop a packet is to receive it without forwarding it.  OpenFlow
+   explicitly specifies forwarding actions.  Thus, a flow with an
+   empty set of actions does not forward packets anywhere, causing
+   them to be dropped.  You can specify an empty set of actions with
+   "actions=" on the ovs-ofctl command line.  For example:
 
        ovs-ofctl add-flow br0 priority=65535,actions=
 
@@ -1249,6 +1270,9 @@ A: An empty set of actions causes a packet to be dropped.  You can
 
        ovs-ofctl add-flow br0 priority=65535,actions=drop
 
+   "drop" is not an action, either in OpenFlow or Open vSwitch.
+   Rather, it is only a way to say that there are no actions.
+
 Q: I added a flow to send packets out the ingress port, like this:
 
        ovs-ofctl add-flow br0 in_port=2,actions=2