Hi Martin, I meant requiring the originators to add themselves (I can think of workarounds to have it work implicitly, but they are compiler/architecture specific).
This feature is not only useful for debugging, it can also be used to deploy multiple NOX controllers to control a single network: On each controller *capture a set of ofp_msg_events* (e.g., only a small portion of packet_in events change the controller state) and *replay/dispatch* them on the others. We need to discard any outgoing ofp packets caused by the replayed events and for that we need to keep track of what events triggered other events/messages. Also, to find out which events are *important* (i.e., alter the controller state), the controller and the running applications need to mark events explicitly. In other words, it is the controller/application developer's job to specify which events should be propagated to other controllers. This part also requires the feature mentioned above. That is because if a non-ofp_msg_event is marked we should be able to trace back to the original ofp_msg_event and mark it. Am I right about the ofp_msg_events being the driving force of NOX operation? And my last question: Is there currently anyway for two NOX instances to synchronize their states for fail over? If not, are there any plans to provide such a feature? Is there any way for a controller/application to store its transient state on disk? What happens in a production network with hundreds of switches when the controller crashes and comes back up in a few seconds? Should it rediscover the topology, host-ip-mac bindings, etc. from scratch? Cheers, Amin > Regarding tracing the event call stack. This would certainly be a useful > debugging tool. However, the nature of events is that the infrastructure is > decoupled from the senders and receivers so it isn't clear to me how we'd > mark the originator an a general way without requiring the originators to > add themselves. I'm certainly open to ideas ... Thanks, Amin _______________________________________________ nox-dev mailing list [email protected] http://noxrepo.org/mailman/listinfo/nox-dev_noxrepo.org
