Eviction is one of the mechanisms provided by the OpenFlow specifications to remove entries from the flow table to avoid overflow. When the flow table in the switch is full, new flow entries can't be added to the flow table, which results in the switch returning an error message to the controller. This results in a problematic situation for the controller, and the controller should take the necessary steps to remove some flow entries from the switch while the switch is in this adverse condition. To avoid this situation and come out of this problematic scenario, the OpenFlow specification defines two mechanisms, as follows:
With eviction enabled on a particular flow table, the switch itself removes a flow entry from the flow table based on some specific criteria of the flow entry. An OFP_TABLE_MOD
message is used to...