[spp] [PATCH 04/28] docs: add spp_vf design section

[ogawa.yasufumi@lab.ntt.co.jp]

From: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>

Signed-off-by: Yasufumi Ogawa <ogawa.yasufumi@lab.ntt.co.jp>
---
 docs/guides/spp_vf/design.rst | 88 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 docs/guides/spp_vf/design.rst

diff --git a/docs/guides/spp_vf/design.rst b/docs/guides/spp_vf/design.rst
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+..  BSD LICENSE
+    Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+    * Neither the name of Intel Corporation nor the names of its
+    contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+Design
+======
+
+Components
+----------
+
+``spp_vf`` supports three types of components, ``forwarder``,
+``merger`` and ``classifier``.
+
+.. image:: images/spp_vf_overview.svg
+   :height: 550 em
+   :width: 550 em
+
+Forwarder
+~~~~~~~~~
+
+This component provides function for packet processing from one port
+to one port.
+Incoming packets from port are to be transferred to specific one port.
+The direction of this transferring is specified by ``port`` command.
+The concept of port is described later of this section.
+
+Merger
+~~~~~~
+
+This component provides packet forwarding function from multiple ports
+to one port.
+Incoming packets from multiple ports are to be transferred to one
+specific port.
+The flow of this merging process is specified by `port` command.
+
+Classifier
+~~~~~~~~~~
+
+This component provides packet forwarding function from one port to
+one port.
+Classifier has table of virtual MAC address(A). According to this table,
+classifier lookups L2 destination MAC address and determines which port
+to be transferred to incoming packets.
+This component also supports vlan-tag(TPID:0x8100), and has the virtual
+MAC tables for each VID(B). If the TPID of incoming packet equals
+0x8100,
+then lookup these tables(B) and determines which port to be transferred.
+Otherwise, incoming packet is transferred according to table(A).
+
+
+Ports
+-----
+
+``spp_vf`` supports three types of PMDs, ``phy`` (Physical NIC),
+``ring`` (Ring PMD) and ``vhost`` (vhsot PMD).
+Using ``phy`` port, component can get incoming packets from outside host
+and transfer the packet to specific physical NIC.
+Using ``ring`` port, variety of combination of components can be
+configured.
+And through ``vhost`` port component can transfer packets from/to VMs.
+``port`` can also control vlan tagging and untagging.
-- 
2.13.1