[spp] [PATCH 04/28] doc: add spp_vf.md

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

From: Hiroyuki Nakamura <nakamura.hioryuki@po.ntt-tx.co.jp>

This is a top level document for spp_vf. setup_guide or other
documents are refererd from it.

Signed-off-by: Naoki Takada <takada.naoki@lab.ntt.co.jp>
---
 docs/spp_vf/spp_vf.md | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 docs/spp_vf/spp_vf.md

diff --git a/docs/spp_vf/spp_vf.md b/docs/spp_vf/spp_vf.md
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+# SPP_VF
+
+SPP_VF is a SR-IOV like network functionality using DPDK for NFV.
+
+![spp_vf_overview](spp_vf_overview.svg)
+
+## Overview
+
+The application distributes incoming packets depends on MAC address
+similar to SR-IOV functionality.
+Network configuration is defined in JSON config file which is imported
+while launching the application.
+The configuration is able to change by sending commnad from spp after
+initialization.
+
+SPP_VF is a multi-thread application.
+It consists of manager thread and forwarder threads.
+There are three types of forwarder for 1:1, 1:N and N:1.
+
+  * forward: 1:1
+  * classifier_mac: 1:N (Destination is determined by MAC address)
+  * merge: N:1
+
+This is an example of network configration, in which one classifier_mac,
+one merger and four forwarders are runnig in spp_vf process for two
+destinations of vhost interface.
+Incoming packets from rx on host1 are sent to each of vhosts on guest
+by looking MAC address in the packet..
+
+![spp_vf_overview](spp_vf_overview.svg)
+
+## Build the Application
+
+See [setup_guide](setup_guide.md).
+
+## Running the Application
+
+See [how_to_use](how_to_use.md).
+
+## Explanation
+
+The following sections provide some explanation of the code.
+
+### Configuration
+
+### Forwarding
+
+### Packet Cloning
-- 
2.13.1