Failover

FlowScale provides the functionality of failover if a designated output port goes offline. FlowScale will divert all traffic directed to the offline port to other online ports. if a port goes down the following will happen

The openflow switch will send a notification to FlowScale indicating that the the port is down
FlowScale, knowing the flows that are directed to that port will update the action field in the flow to another online port
FlowScale will attempt to evenly distribute the flows when moving flows to other ports

FlowScale also provides the possibility of sending a port down notification without the switch itself sending the noitification. This might be necessary in cases when the host connected to the OpenFlow switch becomes unavailable while the NIC is still up. A kernel panic, for example, may cause this scenario. The REST API provides this possibility when it can be indicated if the port is down or up.