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===================
L2 Forwarding Tests
===================

This test application is a basic packet processing application using Intel®
DPDK. It is a layer-2 (L2) forwarding application which takes traffic from
a single RX port and transmits it with few modification on a single TX port.

For a packet received on a RX port (RX_PORT), it would be transmitted from a
TX port (TX_PORT=RX_PORT+1) if RX_PORT is even; otherwise from a TX port
(TX_PORT=RX_PORT-1) if RX_PORT is odd. Before being transmitted, the source
mac address of the packet would be replaced by the mac address of the TX port,
while the destination mac address would be replaced by 00:09:c0:00:00:TX_PORT_ID.

The test application should be run with the wanted paired ports configured using
the coremask parameter via the command line. i.e. port 0 and 1 is a valid pair,
while port 1 and 2 isn't. The test is performed by running the test application
and using a traffic generator. Tests are run with receiving a variety of size of
packets generated by the traffic generator and forwarding back to the traffic
generator. The packet loss and the throughput are the right ones need to be
measured.

The ``l2fwd`` application is run with EAL parameters and parameters for
the application itself. For details about the EAL parameters, see the relevant
DPDK **Getting Started Guide**. This application supports two parameters for
itself.

- ``-p PORTMASK``: hexadecimal bitmask of ports to configure
- ``-q NQ``: number of queue per lcore (default is 1)

Prerequisites
=============

If using vfio the kernel must be >= 3.6+ and VT-d must be enabled in bios.When
using vfio, use the following commands to to load the vfio driver and bind it
to the device under test::

   modprobe vfio
   modprobe vfio-pci
   usertools/dpdk-devbind.py --bind=vfio-pci device_bus_id

Assume port 0 and 1 are connected to the traffic generator, to run the test
application in linuxapp environment with 4 lcores, 2 ports and 8 RX queues
per lcore::

    $ ./l2fwd -n 1 -c f -- -q 8 -p 0x3

Also, if the ports to be tested are different, the port mask should be changed.
The lcore used to run the test application and the number of queue used for a
lcore could be changed. For benchmarking, the EAL parameters and the parameters
for the application itself for different test cases should be the same.

Test Case: Port testing
=======================

Assume ``port A`` on packet generator connects to NIC ``port 0``, while ``port B``
on packet generator connects to NIC ``port 1``. Set the destination mac address
of the packet stream to be sent out from ``port A`` to the mac address of
``port 0``, while the destination mac address of the packet stream to be sent out
from ``port B`` to the mac address of ``port 1``. Other parameters of the packet
stream could be anything valid. Then run the test application as below::

    $ ./l2fwd -n 1 -c f -- -q 8 -p 0x3

Trigger the packet generator of bursting packets from ``port A``, then check if
``port 0`` could receive them and ``port 1`` could forward them back. Stop it
and then trigger the packet generator of bursting packets from ``port B``, then
check if ``port 1`` could receive them and ``port 0`` could forward them back.

Test Case: ``64/128/256/512/1024/1500`` bytes packet forwarding test
====================================================================

Set the packet stream to be sent out from packet generator before testing as below.

+-------+---------+---------+---------+-----------+
| Frame |    1q   |    2q   |   4q    |    8 q    |
| Size  |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  64   |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  65   |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  128  |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  256  |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  512  |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  1024 |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  1280 |         |         |         |           |
+-------+---------+---------+---------+-----------+
|  1518 |         |         |         |           |
+-------+---------+---------+---------+-----------+

Then run the test application as below::

    $ ./l2fwd -n 2 -c f -- -q 1 -p 0x3

The -n command is used to select the number of memory channels. It should match the number of memory channels on that setup.

Trigger the packet generator of bursting packets to the port 0 and 1 on the onboard
NIC to be tested. Then measure the forwarding throughput for different packet sizes
and different number of queues.