fixed coding style

[sliver-openvswitch.git] / FAQ

diff --git a/FAQ b/FAQ
index 4a8a5be..2912ae3 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -418,7 +418,11 @@ A: First, why do you want to do this?  Two connected bridges are not
    ports will not work with the userspace datapath, only with the
    kernel module.
 
-Q: Why are there so many different ways to dump flows?
+
+Implementation Details
+----------------------
+
+Q: I hear OVS has a couple of kinds of flows.  Can you tell me about them?
 
 A: Open vSwitch uses different kinds of flows for different purposes:
 
@@ -434,18 +438,27 @@ A: Open vSwitch uses different kinds of flows for different purposes:
         about hidden flows.)
 
       - The Open vSwitch software switch implementation uses a second
-        kind of flow internally.  These flows, called "exact-match"
-        or "datapath" or "kernel" flows, do not support wildcards or
-        priorities and comprise only a single table, which makes them
-        suitable for caching.   OpenFlow flows and exact-match flows
+        kind of flow internally.  These flows, called "datapath" or
+        "kernel" flows, do not support priorities and comprise only a
+        single table, which makes them suitable for caching.  (Like
+        OpenFlow flows, datapath flows do support wildcarding, in Open
+        vSwitch 1.11 and later.)  OpenFlow flows and datapath flows
         also support different actions and number ports differently.
 
-        Exact-match flows are an implementation detail that is
-        subject to change in future versions of Open vSwitch.  Even
-        with the current version of Open vSwitch, hardware switch
-        implementations do not necessarily use exact-match flows.
+        Datapath flows are an implementation detail that is subject to
+        change in future versions of Open vSwitch.  Even with the
+        current version of Open vSwitch, hardware switch
+        implementations do not necessarily use this architecture.
+
+   Users and controllers directly control only the OpenFlow flow
+   table.  Open vSwitch manages the datapath flow table itself, so
+   users should not normally be concerned with it.
+
+Q: Why are there so many different ways to dump flows?
 
-  Each of the commands for dumping flows has a different purpose:
+A: Open vSwitch has two kinds of flows (see the previous question), so
+   it has commands with different purposes for dumping each kind of
+   flow:
 
       - "ovs-ofctl dump-flows <br>" dumps OpenFlow flows, excluding
         hidden flows.  This is the most commonly useful form of flow
@@ -456,7 +469,7 @@ A: Open vSwitch uses different kinds of flows for different purposes:
         including hidden flows.  This is occasionally useful for
         troubleshooting suspected issues with in-band control.
 
-      - "ovs-dpctl dump-flows [dp]" dumps the exact-match flow table
+      - "ovs-dpctl dump-flows [dp]" dumps the datapath flow table
         entries for a Linux kernel-based datapath.  In Open vSwitch
         1.10 and later, ovs-vswitchd merges multiple switches into a
         single datapath, so it will show all the flows on all your
@@ -464,8 +477,8 @@ A: Open vSwitch uses different kinds of flows for different purposes:
         useful for debugging.
 
       - "ovs-appctl dpif/dump-flows <br>", new in Open vSwitch 1.10,
-        dumps exact-match flows for only the specified bridge,
-        regardless of the type.
+        dumps datapath flows for only the specified bridge, regardless
+        of the type.
 
 
 Performance