Changes between Version 5 and Version 6 of Internal/OpenFlow/Controllers/MultiCtl/FLInternals

Timestamp:

Sep 7, 2012, 7:25:24 PM (12 years ago)

Author:

akoshibe

Comment:

—

Internal/OpenFlow/Controllers/MultiCtl/FLInternals

@@ -59 +59 @@
 `OFChannelHandler` is the inner class of `Controller` responsible for listening for incoming connections from switches. When a switch establishes a connection, a new instantiation of `OFSwitchImpl` is created for the switch. `OFSwitchImpl` is a representation of an individual switch, comprised of the channel, DPID, and information gleaned from the FEATURE_REPLY, among other bits and pieces. Changes are made to a switch through the manipulation of the `OFSwitchImpl` representing it.    
 
-Another thing that occurs upon a switch establishing contact (or disappearing) is the dispatch of a switch event. `SwitchUpdate` is the `Controller` inner class responsible for calling a registered `IOFSwitchListener`'s ''addedSwitch()'' or ''removedSwitch()'' methods. This only occurs after the switch state is designated ''READY''.     
+Another thing that occurs upon a switch establishing contact (or disappearing) is the dispatch of a switch event. `SwitchUpdate` is the `Controller` inner class responsible for calling a registered `IOFSwitchListener`'s ''addedSwitch()'' or ''removedSwitch()'' methods.      
 
 === The !OpenFlow Handshake ===
-The !OpenFlow handshake can be outlined as below:
+The switch event is not fired until the switch completes the !OpenFlow handshake. The handshake can be outlined as below:
 
  1. Exchange of HELLO messages 
- 2. Controller: send FEATURES_REQUEST
- 3. switch: send FEATURES_REPLY
- 4. Controller: send GET_CONFIG_REQUEST
- 5. Switch: send GET_CONFIG_REPLY
+ 1. Controller: send FEATURES_REQUEST
+ 1. switch: send FEATURES_REPLY
+ 1. Controller: send GET_CONFIG_REQUEST
+ 1. Switch: send GET_CONFIG_REPLY
 
-Stage 5 is the point where the switch is deemed ''READY'' and listeners are notified of its arrival. The components that execute the handshake are implemented in `Controller` as a collection of methods that are called from ''processOFMessage()''. ''processOFMessage()'' is also responsible for keeping up with the ECHO_REQUEST/REPLY keepalive messages.     
+Stage 5 is the point where ''checkSwitchReady()'' is called, the switch state is set to ''READY'', and listeners are notified of its arrival. The components that execute the handshake are implemented in `Controller` as a collection of methods that are called from ''processOFMessage()''. ''processOFMessage()'' is also responsible for keeping up with the ECHO_REQUEST/REPLY keepalive messages.     
+
+== Handling Messages ==
+Once the handshake is complete and interested parties aware of it, messages to/from the switch can be dispatched to registered `IOFMessageListeners`. The high-level view of the message processing chain is the following:
+ 
+ 1. `OFChannelHandler` receives the message
+ 1. `Controller` dispatches the message to interested services
+ 1. services process the event accordingly 
+ 1. service sends a message to the switch through its `OFSwitchImpl`