| 20 | | Many of the OF switches deployed do not support the whole OF 1.0 spec in the hardware path. |
| | 20 | == Action is SW vs HW path on the switch == |
| | 21 | Many of the OF switches deployed do not support the whole OF 1.0 spec in the hardware path, when an action is sent to the SW path this causes great degradation on the performance. There is no easy way to tell which actions are supported in HW and which actions are supported in SW. Below is a list of known actions that end up is software, that have been discovered after extensive debugging. |
| | 22 | |
| | 23 | == Output on multiple ports == |
| | 24 | An action that sends out a packet over multiple ports is usually performed in software. |
| | 25 | |
| | 26 | '''FlowVisor in the middle note:''' Although sending packets out OFPP_FLOOD port might be in hardware in many switches, when FV is in the path from the controller to the switch it will substitute OFPP_FLOOD with only the ports that belong to a slice and thus make a multi-port flow mod that will end up in the slow path. |
| | 27 | |
