ofagent-l2pop

Change-Id: I215dd02c21afe499e238a66b168f15fd120454cb

specs/juno/ofagent-l2pop.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 l2pop support
+==========================================
+
+https://blueprints.launchpad.net/neutron/+spec/ofagent-l2pop
+
+implement l2pop support for ofagent agent.
+
+Problem description
+===================
+
+* many packets sent to tunnels because of:
+    * tenant unawareness; no need to forward a packet to nodes
+      which doesn't run endpoints (typically VMs) belonging to the tenant.
+    * broadcasts, namely arp requests
+
+see `L2population_blueprint`_ for more discussions.
+
+.. _L2population_blueprint: https://wiki.openstack.org/wiki/L2population_blueprint
+
+Proposed change
+===============
+
+* implement l2pop-based tunnel management as it's done in ovs
+
+* implement local arp responder by handling packet-ins
+
+Alternatives
+------------
+
+local arp responder part can be implemented differently.
+for example, using nicira extensions as described in `Ovs-flow-logic`_.
+however it isn't a choice for ofagent as there's no way to implement such
+a flow-based arp responder without vendor extensions.
+
+.. _Ovs-flow-logic: https://wiki.openstack.org/wiki/Ovs-flow-logic#OVS_flows_logic_with_local_ARP_responder
+
+Data model impact
+-----------------
+
+none
+
+REST API impact
+---------------
+
+none
+
+Security impact
+---------------
+
+none
+
+Notifications impact
+--------------------
+
+none
+
+Other end user impact
+---------------------
+
+none
+
+Performance Impact
+------------------
+
+this would naturally improve performance.
+
+see `L2population_blueprint`_ for more discussions.
+
+Other deployer impact
+---------------------
+
+none
+
+Developer impact
+----------------
+
+none
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  yamamoto
+
+Other contributors:
+  kakuma
+
+Work Items
+----------
+
+* implement l2pop-based tunnel management as it's done in ovs.
+  the following is working implementation of this.
+
+  https://review.openstack.org/#/c/87440/
+
+* implement local arp respoder by handling packet-ins
+  the following is working implementation of this.
+
+  https://review.openstack.org/#/c/94183/
+
+Dependencies
+============
+
+none
+
+Testing
+=======
+
+ryu/ofagent third party testing would find regressions.
+
+Documentation Impact
+====================
+
+none
+
+References
+==========
+
+* https://blueprints.launchpad.net/neutron/+spec/l2-population
+* https://wiki.openstack.org/wiki/L2population_blueprint
+* https://wiki.openstack.org/wiki/Neutron/OFAgent/Todo
+* https://wiki.openstack.org/wiki/Neutron/OFAgent/FlowTable
+* https://github.com/yamt/ryu/blob/arp-proxy/ryu/app/arp_proxy.py