Neutron/OFAgent/ComparisonWithOVS

Two neutron agents, openvswitch and ofagent, implement mostly same functionalities in different ways. The following is a summary of the differences.

	openvswitch	ofagent
Advantages	Possibly can achieve better performance using Open vSwitch(OVS) specific advanced features like Nicira Extensions (NX) and patch ports.	More portable to switches other than OVS. Easier to handle asynchronous messages because it's a full featured OpenFlow controller.
OpenFlow version	OpenFlow 1.0 + NX	OpenFlow 1.3 without vendor extensions
How to compose flows?	ovs-ofctl command line arguments (plain texts)	Use Ryu ofproto library (python objects)
How to install flows into a switch?	Invoke ovs-ofctl command	An OpenFlow controller embedded in the agent sends messages to the switch
Supported switches	OVS only	OpenFlow 1.3 switches including OVS (planned)
Neutron plugin	openvswitch plugin (planned to be deprecated) or ML2 plugin	ML2 plugin
Port monitoring	Periodic poll of ovsdb via ovs-vsctl command	OpenFlow port statistics and notification (planned)
Device ID	Neutron port ID (UUID) stored in ovsdb	Port name as linuxbridge (planned)
"internal" VLAN	802.1q tagged VLAN	OpenFlow metadata (planned)
Local ARP responder	Install NX flows for each FDB entries (planned)	The embedded OpenFlow controller handles packet-ins and sends back ARP responses (planned)
br-tun		Planned to integrate br-tun and br-int because patch ports are OVS-specific.