Neutron/OFAgent/Todo

OFAgent Todo
- Reduce OVS dependencies
  - patch ports, multiple logical bridges
    - https://blueprints.launchpad.net/neutron/+spec/ofagent-merge-bridges
    - https://wiki.openstack.org/wiki/Neutron/OFAgent/FlowTable
    - implement learning based on flows and packet-in. possibly with l2pop.
  - OVSDB
    - port scanning
      - currently periodically scannig the list of ports and its status using ovs-vsctl
      - use openflow port desc stats and ofp_port_status instead
    - port external id
      - there's no pure-openflow way to associate openstack device uuids to OFP ports.
      - probably use tapXXXX, which is available as ofp_port.name. ML2 plugin already accepts tapXXXX for linuxbridge.
    - add-br, set-controller, set bridge protocols
      - factor out to "OVS" sub-driver
      - use OF-Config
      - move the one-time setup code to devstack
  - port-based VLAN
    - currently using ovs-vsctl to set up port-based VLANs
    - install appropriate flows to push/pop tags instead
  - tunnel ports
    - factor out the code into "OVS" sub-driver.
  - the way to configure physical networks
    - it would be more straightforward to specify an interface (eth0) rather than a bridge (br-eth0)
    - this will be user-visible changes
  - stop assuming the existence of local ports
    - eg. setup_physical_bridges
    - not a big deal
- neutron interface driver
- nova interface driver
- security group. ideally implement with flows.
  - cf. https://wiki.openstack.org/wiki/Neutron/blueprint_ovs-firewall-driver
- l2pop
  - https://blueprints.launchpad.net/neutron/+spec/ofagent-l2pop
  - port l2pop-based tunnel management from OVS agent
  - implement local arp responder
    - experimental arp proxy https://github.com/yamt/ryu/blob/arp-proxy/ryu/app/arp_proxy.py