[PATCH 2/3] docs:tun/tap PMD information

[Keith Wiles <keith.wiles@intel.com>]

Signed-off-by: Keith Wiles <keith.wiles@intel.com>
---
 doc/guides/nics/tap.rst | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 doc/guides/nics/tap.rst

diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
new file mode 100644
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+..  BSD LICENSE
+    Copyright(c) 2016 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.
+
+Tun/Tap Poll Mode Driver
+========================================
+
+The rte_eth_tap.c PMD creates a device using TUN/TAP interfaces on the local
+host. The PMD allows for DPDK and the host to communicate using a raw device
+interface on the host and in the DPDK application.
+
+The device created is a TAP device, which sends/receives packet in a raw format
+with a L2 header. The usage for a TAP PMD is for connectivity to the local host
+using a TAP interface. When the TAP PMD is initialized it will create a number
+of tap devices in the host accessed via 'ifconfig -a' or 'ip' command. The
+commands can be used to assign and query the virtual like device.
+
+These TAP interfaces can be used with wireshark or tcpdump or Pktgen-DPDK along
+with being able to be used as a network connection to the DPDK application. The
+method enable one or more interfaces is to use the --vdev=eth_tap option on the
+DPDK application  command line. Each --vdev=eth_tap option give will create an
+interface named dtap0, dtap1, ... and so forth.
+
+.. code-block:: console
+
+   The interfaced name can be changed by adding the iface=foo0
+   e.g. --vedv=eth_tap,iface=foo0 --vdev=eth_tap,iface=foo1, ...
+
+.. code-block:: console
+
+   Also the speed of the interface can be changed from 10G to whatever number
+   needed, but the interface does not enforce that speed.
+   e.g. --vdev=eth_tap,iface=foo0,speed=25000
+
+After the DPDK application is started you can send and receive packets on the
+interface using the standard rx_burst/tx_burst APIs in DPDK. From the host point
+of view you can use any host tool like tcpdump, wireshark, ping, Pktgen and
+others to communicate with the DPDK application. The DPDK application may not
+understand network protocols like IPv4/6, UDP or TCP unless the application has
+been written to understand these protocols.
+
+If you need the interface as a real network interface meaning running and has
+a valid IP address then you can do this with the following commands:
+
+.. code-block:: console
+
+   sudo ip link set dtap0 up; sudo ip addr add 192.168.0.250/24 dev dtap0
+   sudo ip link set dtap1 up; sudo ip addr add 192.168.1.250/24 dev dtap1
+
+Please change the IP addresses as you see fit.
+
+If routing is enabled on the host you can also communicate with the DPDK App
+over the internet via a standard socket layer application as long as you account
+for the protocol handing in the application.
+
+If you have a Network Stack in your DPDK application or something like it you
+can utilize that stack to handle the network protocols. Plus you would be able
+to address the interface using an IP address assigned to the internal interface.
-- 
2.8.0.GIT