Recently a question came up about the number of responses that may result from a request. I don't recall seeing anything in the spec about this.
There are places where this might be optional (each port stats or flow stats entry could be put in a different message). But there may be places where it's required. For example, when a flow stats request is made, there is a possibility that the size of the response is too big for one OF message (the header length field is 16 bits and there are switches that support tens of thousands of flows). I'd be interested in others' experiences and thoughts. A couple of notes: * Correct me if I'm wrong, but nothing prevents the switch from always responding with small OF messages, e.g., one entry per OF message. Should this be advised against? * All the messages in response to the request will have the same transaction ID. Controllers need to be prepared for this. => Is there an issue here in that we can't identify the last message associated with the transaction? A barrier request could be used by the controller; presumably the barrier reply would get queued behind the previous transaction response. Might be considered expensive for every stats query. _______________________________________________ openflow-discuss mailing list [email protected] https://mailman.stanford.edu/mailman/listinfo/openflow-discuss
