If you set up OVS to run with an OF controller and you try to add two flow rules that are identical except for the priority, is that allowed?
Is there anything in the OpenFlow specification that speaks to this? (I did a quick scan of the spec and couldn't find anything).
The theoretical use case of this might come up is if you have a controller with multiple routing apps driving the same switch. If this is not allowed by the OF switch then we would have to put logic in to filter out the redundant rules.
The switch doesn't care, it does what the controller tells it to do. If you add the same rule (with the same priority), the old rule is replaced by the new rule, there will be no duplicate. If you add the same rule with different priority, you will have this rule twice. Note that only the rule with the higher priority will be applied, the rule with lower priority will not be used until the rule with high priority is removed.