9dead00ded
- Moved RST guide to the arch-design folder - Deleted XML files - Updated scripts Change-Id: Id0e38a9cada9dd75cb9c8f3bd2d88ce2f4fd3eac Implements: blueprint archguide-mitaka-rst
47 lines
1.6 KiB
ReStructuredText
47 lines
1.6 KiB
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===========================
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Software-defined networking
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===========================
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Software-defined networking (SDN) is the separation of the data
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plane and control plane. SDN is a popular method of
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managing and controlling packet flows within networks.
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SDN uses overlays or directly controlled layer-2 devices to
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determine flow paths, and as such presents challenges to a
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cloud environment. Some designers may wish to run their
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controllers within an OpenStack installation. Others may wish
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to have their installations participate in an SDN-controlled network.
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Challenges
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~~~~~~~~~~
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SDN is a relatively new concept that is not yet standardized,
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so SDN systems come in a variety of different implementations.
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Because of this, a truly prescriptive architecture is not feasible.
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Instead, examine the differences between an existing and a planned
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OpenStack design and determine where potential conflicts and gaps exist.
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Possible solutions
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~~~~~~~~~~~~~~~~~~
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If an SDN implementation requires layer-2 access because it
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directly manipulates switches, we do not recommend running an
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overlay network or a layer-3 agent.
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If the controller resides within an OpenStack installation,
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it may be necessary to build an ML2 plug-in and schedule the
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controller instances to connect to tenant VLANs that they can
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talk directly to the switch hardware.
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Alternatively, depending on the external device support,
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use a tunnel that terminates at the switch hardware itself.
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Diagram
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-------
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OpenStack hosted SDN controller:
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.. figure:: figures/Specialized_SDN_hosted.png
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OpenStack participating in an SDN controller network:
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.. figure:: figures/Specialized_SDN_external.png
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