debian: Fix exit status of openvswitch-switch init script "status" command.

[openvswitch] / DESIGN

diff --git a/DESIGN b/DESIGN
index 164ada20e09cd60226cedb3d5f6a80e723c6bf6e..211292569ff038dfea63738497417728384bef25 100644 (file)
--- a/DESIGN
+++ b/DESIGN
@@ -9,8 +9,63 @@ successful deployment.  The end of this document contains contact
 information that can be used to let us know how we can make Open vSwitch
 more generally useful.
 
 information that can be used to let us know how we can make Open vSwitch
 more generally useful.
 

-OpenFlow
-========
+Asynchronous Messages
+=====================
+
+Over time, Open vSwitch has added many knobs that control whether a
+given controller receives OpenFlow asynchronous messages.  This
+section describes how all of these features interact.
+
+First, a service controller never receives any asynchronous messages
+unless it explicitly configures a miss_send_len greater than zero with
+an OFPT_SET_CONFIG message.
+
+Second, OFPT_FLOW_REMOVED and NXT_FLOW_REMOVED messages are generated
+only if the flow that was removed had the OFPFF_SEND_FLOW_REM flag
+set.
+
+Third, OFPT_PACKET_IN and NXT_PACKET_IN messages are sent only to
+OpenFlow controller connections that have the correct connection ID
+(see "struct nx_controller_id" and "struct nx_action_controller"):
+
+    - For packet-in messages generated by a NXAST_CONTROLLER action,
+      the controller ID specified in the action.
+
+    - For other packet-in messages, controller ID zero.  (This is the
+      default ID when an OpenFlow controller does not configure one.)
+
+Finally, Open vSwitch consults a per-connection table indexed by the
+message type, reason code, and current role.  The following table
+shows how this table is initialized by default when an OpenFlow
+connection is made.  An entry labeled "yes" means that the message is
+sent, an entry labeled "---" means that the message is suppressed.
+
+                                             master/
+  message and reason code                     other     slave
+  ----------------------------------------   -------    -----
+  OFPT_PACKET_IN / NXT_PACKET_IN
+    OFPR_NO_MATCH                              yes       ---
+    OFPR_ACTION                                yes       ---
+    OFPR_INVALID_TTL                           ---       ---
+
+  OFPT_FLOW_REMOVED / NXT_FLOW_REMOVED
+    OFPRR_IDLE_TIMEOUT                         yes       ---
+    OFPRR_HARD_TIMEOUT                         yes       ---
+    OFPRR_DELETE                               yes       ---
+
+  OFPT_PORT_STATUS
+    OFPPR_ADD                                  yes       yes
+    OFPPR_DELETE                               yes       yes
+    OFPPR_MODIFY                               yes       yes
+
+The NXT_SET_ASYNC_CONFIG message directly sets all of the values in
+this table for the current connection.  The
+OFPC_INVALID_TTL_TO_CONTROLLER bit in the OFPT_SET_CONFIG message
+controls the setting for OFPR_INVALID_TTL for the "master" role.
+
+
+OFPAT_ENQUEUE
+=============

 
 The OpenFlow 1.0 specification requires the output port of the OFPAT_ENQUEUE
 action to "refer to a valid physical port (i.e. < OFPP_MAX) or OFPP_IN_PORT".
 
 The OpenFlow 1.0 specification requires the output port of the OFPAT_ENQUEUE
 action to "refer to a valid physical port (i.e. < OFPP_MAX) or OFPP_IN_PORT".