gateway.
+Action Reproduction
+===================
+
+It seems likely that many controllers, at least at startup, use the
+OpenFlow "flow statistics" request to obtain existing flows, then
+compare the flows' actions against the actions that they expect to
+find. Before version 1.8.0, Open vSwitch always returned exact,
+byte-for-byte copies of the actions that had been added to the flow
+table. The current version of Open vSwitch does not always do this in
+some exceptional cases. This section lists the exceptions that
+controller authors must keep in mind if they compare actual actions
+against desired actions in a bytewise fashion:
+
+ - Open vSwitch zeros padding bytes in action structures,
+ regardless of their values when the flows were added.
+
+ - Open vSwitch "normalizes" the instructions in OpenFlow 1.1
+ (and later) in the following way:
+
+ * OVS sorts the instructions into the following order:
+ Apply-Actions, Clear-Actions, Write-Actions,
+ Write-Metadata, Goto-Table.
+
+ * OVS drops Apply-Actions instructions that have empty
+ action lists.
+
+ * OVS drops Write-Actions instructions that have empty
+ action sets.
+
+Please report other discrepancies, if you notice any, so that we can
+fix or document them.
+
+
Suggestions
===========