FAQ: Explain how to drop packets.

[sliver-openvswitch.git] / FAQ

diff --git a/FAQ b/FAQ
index a99f808..186f3ac 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -9,12 +9,13 @@ General
 Q: What is Open vSwitch?
 
 A: Open vSwitch is a production quality open source software switch
-   designed to be used as a vswitch in virtualized server environments.  A
-   vswitch forwards traffic between different VMs on the same physical host
-   and also forwards traffic between VMs and the physical network.  Open
-   vSwitch supports standard management interfaces (e.g. sFlow, NetFlow,
-   RSPAN, CLI), and is open to programmatic extension and control using
-   OpenFlow and the OVSDB management protocol.
+   designed to be used as a vswitch in virtualized server
+   environments.  A vswitch forwards traffic between different VMs on
+   the same physical host and also forwards traffic between VMs and
+   the physical network.  Open vSwitch supports standard management
+   interfaces (e.g. sFlow, NetFlow, IPFIX, RSPAN, CLI), and is open to
+   programmatic extension and control using OpenFlow and the OVSDB
+   management protocol.
 
    Open vSwitch as designed to be compatible with modern switching
    chipsets.  This means that it can be ported to existing high-fanout
@@ -113,7 +114,6 @@ A: You can start by joining the mailing lists and helping to answer
        http://openvswitch.org/mlists/
 
 
-
 Releases
 --------
 
@@ -154,6 +154,11 @@ A: The following table lists the Linux kernel versions against which the
    It should build against almost any kernel, certainly against 2.6.18
    and later.
 
+Q: What Linux kernel versions does IPFIX flow monitoring work with?
+
+A: IPFIX flow monitoring requires the Linux kernel module from Open
+   vSwitch version 1.10.90 or later.
+
 Q: Should userspace or kernel be upgraded first to minimize downtime?
 
    In general, the Open vSwitch userspace should be used with the
@@ -833,8 +838,8 @@ A: Do you have a controller configured on br0 (as the commands above
    can refer to the answer there for more information.
 
 
-Controllers
------------
+Using OpenFlow (Manually or Via Controller)
+-------------------------------------------
 
 Q: What versions of OpenFlow does Open vSwitch support?
 
@@ -846,7 +851,7 @@ A: Open vSwitch 1.9 and earlier support only OpenFlow 1.0 (plus
    for OpenFlow 1.2 and 1.3.  On these versions of Open vSwitch, the
    following command enables OpenFlow 1.0, 1.2, and 1.3 on bridge br0:
 
-       ovs-vsctl set bridge br0 protocols=openflow10,openflow12,openflow13
+       ovs-vsctl set bridge br0 protocols=OpenFlow10,OpenFlow12,OpenFlow13
 
    Support for OpenFlow 1.1 is incomplete enough that it cannot yet be
    enabled, even experimentally.
@@ -1095,6 +1100,23 @@ A: To debug network behavior problems, trace the path of a packet,
    problem.  If not, then follow the ARP reply back to the origin, in
    reverse.
 
+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:
+
+       ovs-ofctl add-flow br0 priority=65535,actions=
+
+   would cause every packet entering switch br0 to be dropped.
+
+   You can write "drop" explicitly if you like.  The effect is the
+   same.  Thus, the following command also causes every packet
+   entering switch br0 to be dropped:
+
+       ovs-ofctl add-flow br0 priority=65535,actions=drop
+
+
 Contact 
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