ofagent-flow-based-tunneling

Change-Id: I183c2933ddd8581ca8cc28f12cbb3f0ec696669a

specs/kilo/ofagent-flow-based-tunneling.rst

@@ -0,0 +1,163 @@
+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+=============================
+OFAgent: Flow-based tunneling
+=============================
+
+https://blueprints.launchpad.net/neutron/+spec/ofagent-flow-based-tunneling
+
+make ofagent use flow-based tunneling rather than
+the current port-based tunneling.
+
+Problem Description
+===================
+
+ofagent creates tunnel ports for each peer nodes.
+It's unscalable and complex.
+
+Proposed Change
+===============
+
+use flow-based tunneling, using tun_ipv4_src/tun_ipv4_dst NXMs.
+(in addition to tun_id OXM, which is currently used by ofagent)
+
+Note: while the use of NXMs contradicts to the one of goals of
+ofagent, i.e. being portable to other switch implementations,
+it isn't a problem right now because:
+
+- the tunneling support is OVS-dependent anyway
+
+- i've heard that the future versions of OpenFlow aims to the same direction.
+  there seems to be no publically available reference for this, though.
+
+Alternatives
+------------
+
+none
+
+Data Model Impact
+-----------------
+
+none
+
+REST API Impact
+---------------
+
+none
+
+Security Impact
+---------------
+
+none
+
+Notifications Impact
+--------------------
+
+none
+
+Other End User Impact
+---------------------
+
+none
+
+Performance Impact
+------------------
+
+none
+
+IPv6 Impact
+-----------
+
+none
+
+Other Deployer Impact
+---------------------
+
+none
+
+Developer Impact
+----------------
+
+code would get simpler and easier to maintain.
+
+Community Impact
+----------------
+
+none
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  yamamoto
+
+Other contributors:
+  kakuma
+
+Work Items
+----------
+
+* tweak L2populationRpcCallBackTunnelMixin api so that it can handle
+  the "a single tunnel port for many networks" situation more naturally
+
+* tweak how ofagent sets up tunnel ports
+
+* tweak ofagent flows accordingly
+
+Dependencies
+============
+
+none
+
+Testing
+=======
+
+Tempest Tests
+-------------
+
+ideally multi-node testing is necessary.
+however i don't plan to cover it by this blueprint.
+
+Functional Tests
+----------------
+
+none
+
+API Tests
+---------
+
+no api change thus no additional tests.
+
+Documentation Impact
+====================
+
+User Documentation
+------------------
+
+should document new requirement (ryu>=3.15) for relevant NXMs support
+
+Developer Documentation
+-----------------------
+
+none
+
+References
+==========
+
+the current implementation of this blueprint:
+
+- https://review.openstack.org/#/c/130676/
+- https://review.openstack.org/#/c/130677/
+
+as far as i know, NXMs are only documentated in Open vSwitch
+source code:
+
+- https://github.com/openvswitch/ovs/blob/e9bbe84b6b51eb9671451504b79c7b79b7250c3b/lib/meta-flow.h#L335
+- https://github.com/openvswitch/ovs/blob/e9bbe84b6b51eb9671451504b79c7b79b7250c3b/lib/meta-flow.h#L353