+(#) "modify" and "modify-strict" only add a new flow if the flow_mod
+ does not match on any bits of the flow cookie
+
+OpenFlow 1.2
+------------
+
+OpenFlow 1.2 makes these changes:
+
+ - Only "add" commands ever add flows, "modify" and "modify-strict"
+ never do.
+
+ - A new flag OFPFF_RESET_COUNTS now controls whether "modify" and
+ "modify-strict" reset counters, whereas previously they never
+ reset counters (except when they inserted a new flow).
+
+ MODIFY DELETE
+ ADD MODIFY STRICT DELETE STRICT
+ === ====== ====== ====== ======
+match on priority yes --- yes --- yes
+match on out_port --- --- --- yes yes
+match on flow_cookie --- yes yes yes yes
+match on table_id yes yes yes yes yes
+controller chooses table_id yes yes yes
+updates flow_cookie yes --- ---
+updates OFPFF_SEND_FLOW_REM yes --- ---
+honors OFPFF_CHECK_OVERLAP yes --- ---
+updates idle_timeout yes --- ---
+updates hard_timeout yes --- ---
+resets idle timer yes --- ---
+resets hard timer yes yes yes
+zeros counters yes & &
+may add a new flow yes --- ---
+sends flow_removed message --- --- --- % %
+
+(%) "delete" and "delete_strict" generates a flow_removed message if
+ the deleted flow or flows have the OFPFF_SEND_FLOW_REM flag set.
+ (Each controller can separately control whether it wants to
+ receive the generated messages.)
+
+(&) "modify" and "modify-strict" reset counters if the
+ OFPFF_RESET_COUNTS flag is specified.
+
+OpenFlow 1.3
+------------
+
+OpenFlow 1.3 makes these changes:
+
+ - Behavior for a table_id of 255 is now defined, for "delete" and
+ "delete-strict" commands, as meaning to delete from all tables.
+ A table_id of 255 is now explicitly invalid for other commands.
+
+ - New flags OFPFF_NO_PKT_COUNTS and OFPFF_NO_BYT_COUNTS for "add"
+ operations.
+
+The table for 1.3 is the same as the one shown above for 1.2.
+