ofagent: physical interface mappings

Change-Id: I7b2e2775b097e85d238b983b4baffcfef1b9c3eb

specs/juno/ofagent-physical-interface-mappings.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+====================================
+ofagent: physical interface mappings
+====================================
+
+https://blueprints.launchpad.net/neutron/+spec/ofagent-physical-interface-mappings
+
+Problem description
+===================
+
+ofagent currently has "bridge_mappings" config option inherited
+from ovs agent.  it assumes multiple bridges are available.
+the assumption is ok for ovs agent but not desirable for ofagent.
+
+Proposed change
+===============
+
+* introduce "physical_interface_mappings" config option for ofagent
+  with a similar semantics to linuxbridge.
+
+* deprecate bridge_mappings for ofagent later.
+
+* document the upgrade procedure for deployers.
+
+Alternatives
+------------
+
+no alternative i can think of right now.
+
+Data model impact
+-----------------
+
+none
+
+REST API impact
+---------------
+
+none
+
+Security impact
+---------------
+
+none
+
+Notifications impact
+--------------------
+
+none
+
+Other end user impact
+---------------------
+
+none
+
+Performance Impact
+------------------
+
+none
+
+Other deployer impact
+---------------------
+
+a deployer who's using ofagent might need to tweak his configuration.
+
+* create veth pairs for each bridges in the existing bridge_mappings
+
+* use physical_interface_mappings instead of bridge_mappings
+
+Developer impact
+----------------
+
+none
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  yamamoto
+
+Other contributors:
+  kakuma
+
+Work Items
+----------
+
+see "Proposed change" section.
+
+Dependencies
+============
+
+we need to stop installing flows in physical bridges.
+we plan to do that in the following.
+
+* https://review.openstack.org/#/c/98702/
+
+Testing
+=======
+
+ryu/ofagent third party testing would find regressions.
+
+Documentation Impact
+====================
+
+* document the upgrade procedure for deployers.
+
+References
+==========
+
+none