path: root/docs/test_spec/vswitchperf_ltd.rst

CHARACTERIZE VSWITCH PERFORMANCE FOR TELCO NFV USE CASES LEVEL TEST DESIGN
==========================================================================

.. contents:: Table of Contents

1. Introduction
===============

The objective of the OPNFV project titled
**“Characterize vSwitch Performance for Telco NFV Use Cases”**, is to
evaluate a virtual switch to identify its suitability for a Telco
Network Function Virtualization (NFV) environment. The intention of this
Level Test Design (LTD) document is to specify the set of tests to carry
out in order to objectively measure the current characteristics of a
virtual switch in the Network Function Virtualization Infrastructure
(NFVI) as well as the test pass criteria. The detailed test cases will
be defined in `Section 2 <#DetailsOfTheLevelTestDesign>`__, preceded by
the `Document identifier <#DocId>`__ and the `Scope <#Scope>`__.

This document is currently in draft form.

1.1. Document identifier
------------------------

The document id will be used to uniquely
identify versions of the LTD. The format for the document id will be:
OPNFV\_vswitchperf\_LTD\_ver\_NUM\_MONTH\_YEAR\_STATUS, where by the
status is one of: draft, reviewed, corrected or final. The document id
for this version of the LTD is:
OPNFV\_vswitchperf\_LTD\_ver\_1.6\_Jan\_15\_DRAFT.

1.2. Scope
----------

The main purpose of this project is to specify a suite of
performance tests in order to objectively measure the current packet
transfer characteristics of a virtual switch in the NFVI. The intent of
the project is to facilitate testing of any virtual switch. Thus, a
generic suite of tests shall be developed, with no hard dependencies to
a single implementation. In addition, the test case suite shall be
architecture independent.

The test cases developed in this project shall not form part of a
separate test framework, all of these tests may be inserted into the
Continuous Integration Test Framework and/or the Platform Functionality
Test Framework - if a vSwitch becomes a standard component of an OPNFV
release.

1.3. References
---------------

*  `RFC 1242 Benchmarking Terminology for Network Interconnection
   Devices <http://www.ietf.org/rfc/rfc1242.txt>`__
*  `RFC 2544 Benchmarking Methodology for Network Interconnect
   Devices <http://www.ietf.org/rfc/rfc2544.txt>`__
*  `RFC 2285 Benchmarking Terminology for LAN Switching
   Devices <http://www.ietf.org/rfc/rfc2285.txt>`__
*  `RFC 2889 Benchmarking Methodology for LAN Switching
   Devices <http://www.ietf.org/rfc/rfc2889.txt>`__
*  `RFC 3918 Methodology for IP Multicast
   Benchmarking <http://www.ietf.org/rfc/rfc3918.txt>`__
*  `RFC 4737 Packet Reordering
   Metrics <http://www.ietf.org/rfc/rfc4737.txt>`__
*  `RFC 5481 Packet Delay Variation Applicability
   Statement <http://www.ietf.org/rfc/rfc5481.txt>`__
*  `RFC 6201 Device Reset
   Characterization <http://tools.ietf.org/html/rfc6201>`__

2. Details of the Level Test Design
===================================

This section describes the features to be tested (`cf. 2.1
<#FeaturesToBeTested>`__), the test approach (`cf. 2.2 <#Approach>`__);
it also identifies the sets of test cases or scenarios (`cf. 2.3
<#TestIdentification>`__) along with the pass/fail criteria (`cf. 2.4
<#PassFail>`__) and the test deliverables (`cf. 2.5 <#TestDeliverables>`__).

2.1. Features to be tested
--------------------------

Characterizing virtual switches (i.e. Device Under Test (DUT) in this document)
includes measuring the following performance metrics:

- **Throughput** as defined by `RFC1242
  <https://www.rfc-editor.org/rfc/rfc1242.txt>`__: The maximum rate at which
  **none** of the offered frames are dropped by the DUT. The maximum frame
  rate and bit rate that can be transmitted by the DUT without any error
  should be recorded. Note there is an equivalent bit rate and a specific
  layer at which the payloads contribute to the bits. Errors and
  improperly formed frames or packets are dropped.
- **Packet delay** introduced by the DUT and its cumulative effect on
  E2E networks. Frame delay can be measured equivalently.
- **Packet delay variation**: measured from the perspective of the
  VNF/application. Packet delay variation is sometimes called "jitter".
  However, we will avoid the term "jitter" as the term holds different
  meaning to different groups of people. In this document we will
  simply use the term packet delay variation. The preferred form for this
  metric is the PDV form of delay variation defined in `RFC5481
  <https://www.rfc-editor.org/rfc/rfc5481.txt>`__. The most relevant
  measurement of PDV considers the delay variation of a single user flow,
  as this will be relevant to the size of end-system buffers to compensate
  for delay variation. The measurement system's ability to store the
  delays of individual packets in the flow of interest is a key factor
  that determines the specific measurement method. At the outset, it is
  ideal to view the complete PDV distribution. Systems that can capture
  and store packets and their delays have the freedom to calculate the
  reference minimum delay and to determine various quantiles of the PDV
  distribution accurately (in post-measurement processing routines).
  Systems without storage must apply algorithms to calculate delay and
  statistical measurements on the fly. For example, a system may store
  temporary estimates of the mimimum delay and the set of (100) packets
  with the longest delays during measurement (to calculate a high quantile,
  and update these sets with new values periodically.
  In some cases, a limited number of delay histogram bins will be
  available, and the bin limits will need to be set using results from
  repeated experiments. See section 8 of `RFC5481
  <https://www.rfc-editor.org/rfc/rfc5481.txt>`__.
- **Packet loss** (within a configured waiting time at the receiver): All
  packets sent to the DUT should be accounted for.
- **Burst behaviour**: measures the ability of the DUT to buffer packets.
- **Packet re-ordering**: measures the ability of the device under test to
  maintain sending order throughout transfer to the destination.
- **Packet correctness**: packets or Frames must be well-formed, in that
  they include all required fields, conform to length requirements, pass
  integrity checks, etc.
- **Availability and capacity** of the DUT i.e. when the DUT is fully “up”
  and connected:

  - Includes power consumption of the CPU (in various power states) and
    system.
  - Includes CPU utilization.
  - Includes the number of NIC interfaces supported.
  - Includes headroom of VM workload processing cores (i.e. available
    for applications).


2.2. Approach
==============

In order to determine the packet transfer characteristics of a virtual
switch, the tests will be broken down into the following categories:

2.2.1 Test Categories
----------------------
- **Throughput Tests** to measure the maximum forwarding rate (in
  frames per second or fps) and bit rate (in Mbps) for a constant load
  (as defined by `RFC1242 <https://www.rfc-editor.org/rfc/rfc1242.txt>`__)
  without traffic loss.
- **Packet and Frame Delay Tests** to measure average, min and max
  packet and frame delay for constant loads.
- **Stream Performance Tests** (TCP, UDP) to measure bulk data transfer
  performance, i.e. how fast systems can send and receive data through
  the virtual switch.
- **Request/Response Performance** Tests (TCP, UDP) the measure the
  transaction rate through the virtual switch.
- **Packet Delay Tests** to understand latency distribution for
  different packet sizes and over an extended test run to uncover
  outliers.
- **Scalability Tests** to understand how the virtual switch performs
  as the number of flows, active ports, complexity of the forwarding
  logic's configuration... it has to deal with increases.
- **Control Path and Datapath Coupling** Tests, to understand how
  closely coupled the datapath and the control path are as well as the
  effect of this coupling on the performance of the DUT.
- **CPU and Memory Consumption Tests** to understand the virtual
  switch’s footprint on the system, this includes:

  * CPU utilization
  * Cache utilization
  * Memory footprint
  * Time To Establish Flows Tests.

- **Noisy Neighbour Tests**, to understand the effects of resource
  sharing on the performance of a virtual switch.

**Note:** some of the tests above can be conducted simultaneously where
the combined results would be insightful, for example Packet/Frame Delay
and Scalability.

2.2.2 Deployment Scenarios
--------------------------
The following represents possible deployments which can help to
determine the performance of both the virtual switch and the datapath
into the VNF:

Physical port → vSwitch → physical port
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  .. code-block:: console

                                                            _
       +--------------------------------------------------+  |
       |              +--------------------+              |  |
       |              |                    |              |  |
       |              |                    v              |  |  Host
       |   +--------------+            +--------------+   |  |
       |   |   phy port   |  vSwitch   |   phy port   |   |  |
       +---+--------------+------------+--------------+---+ _|
                  ^                           :
                  |                           |
                  :                           v
       +--------------------------------------------------+
       |                                                  |
       |                traffic generator                 |
       |                                                  |
       +--------------------------------------------------+


Physical port → vSwitch → VNF → vSwitch → physical port
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  .. code-block:: console

                                                             _
       +---------------------------------------------------+  |
       |                                                   |  |
       |   +-------------------------------------------+   |  |
       |   |                 Application               |   |  |
       |   +-------------------------------------------+   |  |
       |       ^                                  :        |  |
       |       |                                  |        |  |  Guest
       |       :                                  v        |  |
       |   +---------------+           +---------------+   |  |
       |   | logical port 0|           | logical port 1|   |  |
       +---+---------------+-----------+---------------+---+ _|
               ^                                  :
               |                                  |
               :                                  v         _
       +---+---------------+----------+---------------+---+  |
       |   | logical port 0|          | logical port 1|   |  |
       |   +---------------+          +---------------+   |  |
       |       ^                                  :       |  |
       |       |                                  |       |  |  Host
       |       :                                  v       |  |
       |   +--------------+            +--------------+   |  |
       |   |   phy port   |  vSwitch   |   phy port   |   |  |
       +---+--------------+------------+--------------+---+ _|
                  ^                           :
                  |                           |
                  :                           v
       +--------------------------------------------------+
       |                                                  |
       |                traffic generator                 |
       |                                                  |
       +--------------------------------------------------+


Physical port → vSwitch → VNF → vSwitch → VNF → vSwitch → physical port
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  .. code-block:: console

                                                       _
    +----------------------+  +----------------------+  |
    |   Guest 1            |  |   Guest 2            |  |
    |   +---------------+  |  |   +---------------+  |  |
    |   |  Application  |  |  |   |  Application  |  |  |
    |   +---------------+  |  |   +---------------+  |  |
    |       ^       |      |  |       ^       |      |  |
    |       |       v      |  |       |       v      |  |  Guests
    |   +---------------+  |  |   +---------------+  |  |
    |   | logical ports |  |  |   | logical ports |  |  |
    |   |   0       1   |  |  |   |   0       1   |  |  |
    +---+---------------+--+  +---+---------------+--+ _|
            ^       :                 ^       :
            |       |                 |       |
            :       v                 :       v        _
    +---+---------------+---------+---------------+--+  |
    |   |   0       1   |         |   3       4   |  |  |
    |   | logical ports |         | logical ports |  |  |
    |   +---------------+         +---------------+  |  |
    |       ^       |                 ^       |      |  |  Host
    |       |       L-----------------+       v      |  |
    |   +--------------+          +--------------+   |  |
    |   |   phy ports  | vSwitch  |   phy ports  |   |  |
    +---+--------------+----------+--------------+---+ _|
            ^       ^                 :       :
            |       |                 |       |
            :       :                 v       v
    +--------------------------------------------------+
    |                                                  |
    |                traffic generator                 |
    |                                                  |
    +--------------------------------------------------+

Physical port → VNF → vSwitch → VNF → physical port
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  .. code-block:: console

                                                        _
    +----------------------+  +----------------------+   |
    |   Guest 1            |  |   Guest 2            |   |
    |+-------------------+ |  | +-------------------+|   |
    ||     Application   | |  | |     Application   ||   |
    |+-------------------+ |  | +-------------------+|   |
    |       ^       |      |  |       ^       |      |   |  Guests
    |       |       v      |  |       |       v      |   |
    |+-------------------+ |  | +-------------------+|   |
    ||   logical ports   | |  | |   logical ports   ||   |
    ||  0              1 | |  | | 0              1  ||   |
    ++--------------------++  ++--------------------++  _|
        ^              :          ^              :
    (PCI passthrough)  |          |     (PCI passthrough)
        |              v          :              |      _
    +--------++------------+-+------------++---------+   |
    |   |    ||        0   | |    1       ||     |   |   |
    |   |    ||logical port| |logical port||     |   |   |
    |   |    |+------------+ +------------+|     |   |   |
    |   |    |     |                 ^     |     |   |   |
    |   |    |     L-----------------+     |     |   |   |
    |   |    |                             |     |   |   |  Host
    |   |    |           vSwitch           |     |   |   |
    |   |    +-----------------------------+     |   |   |
    |   |                                        |   |   |
    |   |                                        v   |   |
    | +--------------+              +--------------+ |   |
    | | phy port/VF  |              | phy port/VF  | |   |
    +-+--------------+--------------+--------------+-+  _|
        ^                                        :
        |                                        |
        :                                        v
    +--------------------------------------------------+
    |                                                  |
    |                traffic generator                 |
    |                                                  |
    +--------------------------------------------------+

Physical port → vSwitch → VNF
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  .. code-block:: console

                                                          _
    +---------------------------------------------------+  |
    |                                                   |  |
    |   +-------------------------------------------+   |  |
    |   |                 Application               |   |  |
    |   +-------------------------------------------+   |  |
    |       ^                                           |  |
    |       |                                           |  |  Guest
    |       :                                           |  |
    |   +---------------+                               |  |
    |   | logical port 0|                               |  |
    +---+---------------+-------------------------------+ _|
            ^
            |
            :                                            _
    +---+---------------+------------------------------+  |
    |   | logical port 0|                              |  |
    |   +---------------+                              |  |
    |       ^                                          |  |
    |       |                                          |  |  Host
    |       :                                          |  |
    |   +--------------+                               |  |
    |   |   phy port   |  vSwitch                      |  |
    +---+--------------+------------ -------------- ---+ _|
               ^
               |
               :
    +--------------------------------------------------+
    |                                                  |
    |                traffic generator                 |
    |                                                  |
    +--------------------------------------------------+

VNF → vSwitch → physical port
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  .. code-block:: console

                                                          _
    +---------------------------------------------------+  |
    |                                                   |  |
    |   +-------------------------------------------+   |  |
    |   |                 Application               |   |  |
    |   +-------------------------------------------+   |  |
    |                                          :        |  |
    |                                          |        |  |  Guest
    |                                          v        |  |
    |                               +---------------+   |  |
    |                               | logical port  |   |  |
    +-------------------------------+---------------+---+ _|
                                               :
                                               |
                                               v         _
    +------------------------------+---------------+---+  |
    |                              | logical port  |   |  |
    |                              +---------------+   |  |
    |                                          :       |  |
    |                                          |       |  |  Host
    |                                          v       |  |
    |                               +--------------+   |  |
    |                     vSwitch   |   phy port   |   |  |
    +-------------------------------+--------------+---+ _|
                                           :
                                           |
                                           v
    +--------------------------------------------------+
    |                                                  |
    |                traffic generator                 |
    |                                                  |
    +--------------------------------------------------+

VNF → vSwitch → VNF → vSwitch
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  .. code-block:: console

                                                             _
    +-------------------------+  +-------------------------+  |
    |   Guest 1               |  |   Guest 2               |  |
    |   +-----------------+   |  |   +-----------------+   |  |
    |   |   Application   |   |  |   |   Application   |   |  |
    |   +-----------------+   |  |   +-----------------+   |  |
    |                :        |  |       ^                 |  |
    |                |        |  |       |                 |  |  Guest
    |                v        |  |       :                 |  |
    |     +---------------+   |  |   +---------------+     |  |
    |     | logical port 0|   |  |   | logical port 0|     |  |
    +-----+---------------+---+  +---+---------------+-----+ _|
                    :                    ^
                    |                    |
                    v                    :                    _
    +----+---------------+------------+---------------+-----+  |
    |    |     port 0    |            |     port 1    |     |  |
    |    +---------------+            +---------------+     |  |
    |              :                    ^                   |  |
    |              |                    |                   |  |  Host
    |              +--------------------+                   |  |
    |                                                       |  |
    |                     vswitch                           |  |
    +-------------------------------------------------------+ _|

HOST 1(Physical port → virtual switch → VNF → virtual switch →
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Physical port) → HOST 2(Physical port → virtual switch → VNF →
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
virtual switch → Physical port)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  .. code-block:: console

                                                       _
    +----------------------+  +----------------------+  |
    |   Guest 1            |  |   Guest 2            |  |
    |   +---------------+  |  |   +---------------+  |  |
    |   |  Application  |  |  |   |  Application  |  |  |
    |   +---------------+  |  |   +---------------+  |  |
    |       ^       |      |  |       ^       |      |  |
    |       |       v      |  |       |       v      |  |  Guests
    |   +---------------+  |  |   +---------------+  |  |
    |   | logical ports |  |  |   | logical ports |  |  |
    |   |   0       1   |  |  |   |   0       1   |  |  |
    +---+---------------+--+  +---+---------------+--+ _|
            ^       :                 ^       :
            |       |                 |       |
            :       v                 :       v        _
    +---+---------------+--+  +---+---------------+--+  |
    |   |   0       1   |  |  |   |   3       4   |  |  |
    |   | logical ports |  |  |   | logical ports |  |  |
    |   +---------------+  |  |   +---------------+  |  |
    |       ^       |      |  |       ^       |      |  |  Hosts
    |       |       v      |  |       |       v      |  |
    |   +--------------+   |  |   +--------------+   |  |
    |   |   phy ports  |   |  |   |   phy ports  |   |  |
    +---+--------------+---+  +---+--------------+---+ _|
            ^       :                 :       :
            |       +-----------------+       |
            :                                 v
    +--------------------------------------------------+
    |                                                  |
    |                traffic generator                 |
    |                                                  |
    +--------------------------------------------------+



**Note:** For tests where the traffic generator and/or measurement
receiver are implemented on VM and connected to the virtual switch
through vNIC, the issues of shared resources and interactions between
the measurement devices and the device under test must be considered.

**Note:** Some RFC 2889 tests require a full-mesh sending and receiving
pattern involving more than two ports. This possibility is illustrated in the
Physical port → vSwitch → VNF → vSwitch → VNF → vSwitch → physical port
diagram above (with 2 sending and 2 receiving ports, though all ports
could be used bi-directionally).

**Note:** When Deployment Scenarios are used in RFC 2889 address learning
or cache capacity testing, an additional port from the vSwitch must be
connected to the test device. This port is used to listen for flooded
frames.

2.2.3 General Methodology:
--------------------------
To establish the baseline performance of the virtual switch, tests would
initially be run with a simple workload in the VNF (the recommended
simple workload VNF would be `DPDK <http://www.dpdk.org/>`__'s testpmd
application forwarding packets in a VM or vloop\_vnf a simple kernel
module that forwards traffic between two network interfaces inside the
virtualized environment while bypassing the networking stack).
Subsequently, the tests would also be executed with a real Telco
workload running in the VNF, which would exercise the virtual switch in
the context of higher level Telco NFV use cases, and prove that its
underlying characteristics and behaviour can be measured and validated.
Suitable real Telco workload VNFs are yet to be identified.

2.2.3.1 Default Test Parameters
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The following list identifies the default parameters for suite of
tests:

-  Reference application: Simple forwarding or Open Source VNF.
-  Frame size (bytes): 64, 128, 256, 512, 1024, 1280, 1518, 2K, 4k OR
   Packet size based on use-case (e.g. RTP 64B, 256B) OR Mix of packet sizes as
   maintained by the Functest project <https://wiki.opnfv.org/traffic_profile_management>.
-  Reordering check: Tests should confirm that packets within a flow are
   not reordered.
-  Duplex: Unidirectional / Bidirectional. Default: Full duplex with
   traffic transmitting in both directions, as network traffic generally
   does not flow in a single direction. By default the data rate of
   transmitted traffic should be the same in both directions, please
   note that asymmetric traffic (e.g. downlink-heavy) tests will be
   mentioned explicitly for the relevant test cases.
-  Number of Flows: Default for non scalability tests is a single flow.
   For scalability tests the goal is to test with maximum supported
   flows but where possible will test up to 10 Million flows. Start with
   a single flow and scale up. By default flows should be added
   sequentially, tests that add flows simultaneously will explicitly
   call out their flow addition behaviour. Packets are generated across
   the flows uniformly with no burstiness. For multi-core tests should
   consider the number of packet flows based on vSwitch/VNF multi-thread
   implementation and behavior.

-  Traffic Types: UDP, SCTP, RTP, GTP and UDP traffic.
-  Deployment scenarios are:
-  Physical → virtual switch → physical.
-  Physical → virtual switch → VNF → virtual switch → physical.
-  Physical → virtual switch → VNF → virtual switch → VNF → virtual
   switch → physical.
-  Physical → VNF → virtual switch → VNF → physical.
-  Physical → virtual switch → VNF.
-  VNF → virtual switch → Physical.
-  VNF → virtual switch → VNF.

Tests MUST have these parameters unless otherwise stated. **Test cases
with non default parameters will be stated explicitly**.

**Note**: For throughput tests unless stated otherwise, test
configurations should ensure that traffic traverses the installed flows
through the virtual switch, i.e. flows are installed and have an appropriate
time out that doesn't expire before packet transmission starts.

2.2.3.2 Flow Classification
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Virtual switches classify packets into flows by processing and matching
particular header fields in the packet/frame and/or the input port where
the packets/frames arrived. The vSwitch then carries out an action on
the group of packets that match the classification parameters. Thus a
flow is considered to be a sequence of packets that have a shared set of
header field values or have arrived on the same port and have the same
action applied to them. Performance results can vary based on the
parameters the vSwitch uses to match for a flow. The recommended flow
classification parameters for L3 vSwitch performance tests are: the
input port, the source IP address, the destination IP address and the
Ethernet protocol type field. It is essential to increase the flow
time-out time on a vSwitch before conducting any performance tests that
do not measure the flow set-up time. Normally the first packet of a
particular flow will install the flow in the vSwitch which adds an
additional latency, subsequent packets of the same flow are not subject
to this latency if the flow is already installed on the vSwitch.

2.2.3.3 Test Priority
~~~~~~~~~~~~~~~~~~~~~

Tests will be assigned a priority in order to determine which tests
should be implemented immediately and which tests implementations
can be deferred.

Priority can be of following types: - Urgent: Must be implemented
immediately. - High: Must be implemented in the next release. - Medium:
May be implemented after the release. - Low: May or may not be
implemented at all.

2.2.3.4 SUT Setup
~~~~~~~~~~~~~~~~~

The SUT should be configured to its "default" state. The
SUT's configuration or set-up must not change between tests in any way
other than what is required to do the test. All supported protocols must
be configured and enabled for each test set up.

2.2.3.4.1 Port Configuration
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The DUT should be configured with n ports where
n is a multiple of 2. Half of the ports on the DUT should be used as
ingress ports and the other half of the ports on the DUT should be used
as egress ports. Where a DUT has more than 2 ports, the ingress data
streams should be set-up so that they transmit packets to the egress
ports in sequence so that there is an even distribution of traffic
across ports. For example, if a DUT has 4 ports 0(ingress), 1(ingress),
2(egress) and 3(egress), the traffic stream directed at port 0 should
output a packet to port 2 followed by a packet to port 3. The traffic
stream directed at port 1 should also output a packet to port 2 followed
by a packet to port 3.

2.2.3.4.2 Frame Formats
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Frame formats Layer 2 (data link layer) protocols
++++++++++++++++++++++++++++++++++++++++++++++++++
-  Ethernet II

  .. code-block:: console

     +---------------------+--------------------+-----------+
     |   Ethernet Header   |       Payload      | Check Sum |
     +---------------------+--------------------+-----------+
     |_____________________|____________________|___________|
           14 Bytes            46 - 1500 Bytes      4 Bytes

Layer 3 (network layer) protocols
++++++++++++++++++++++++++++++++++

-  IPv4

  .. code-block:: console

     +---------------------+--------------------+--------------------+-----------+
     |   Ethernet Header   |      IP Header     |       Payload      | Check Sum |
     +---------------------+--------------------+--------------------+-----------+
     |_____________________|____________________|____________________|___________|
           14 Bytes            20 bytes             26 - 1480 Bytes      4 Bytes

-  IPv6

  .. code-block:: console

     +---------------------+--------------------+--------------------+-----------+
     |   Ethernet Header   |      IP Header     |       Payload      | Check Sum |
     +---------------------+--------------------+--------------------+-----------+
     |_____________________|____________________|____________________|___________|
           14 Bytes            40 bytes             26 - 1460 Bytes      4 Bytes

Layer 4 (transport layer) protocols
++++++++++++++++++++++++++++++++++++
  - TCP
  - UDP
  - SCTP

  .. code-block:: console

     +---------------------+--------------------+-----------------+--------------------+-----------+
     |   Ethernet Header   |      IP Header     | Layer 4 Header  |       Payload      | Check Sum |
     +---------------------+--------------------+-----------------+--------------------+-----------+
     |_____________________|____________________|_________________|____________________|___________|
           14 Bytes            40 bytes               20 Bytes       6 - 1460 Bytes      4 Bytes

Layer 5 (application layer) protocols
+++++++++++++++++++++++++++++++++++++
  - RTP
  - GTP

  .. code-block:: console

     +---------------------+--------------------+-----------------+--------------------+-----------+
     |   Ethernet Header   |      IP Header     | Layer 4 Header  |       Payload      | Check Sum |
     +---------------------+--------------------+-----------------+--------------------+-----------+
     |_____________________|____________________|_________________|____________________|___________|
           14 Bytes            20 bytes               20 Bytes         Min 6 Bytes       4 Bytes


2.2.3.4.3 Packet Throughput
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
There is a difference between an Ethernet frame,
an IP packet, and a UDP datagram. In the seven-layer OSI model of
computer networking, packet refers to a data unit at layer 3 (network
layer). The correct term for a data unit at layer 2 (data link layer) is
a frame, and at layer 4 (transport layer) is a segment or datagram.

Important concepts related to 10GbE performance are frame rate and
throughput. The MAC bit rate of 10GbE, defined in the IEEE standard 802
.3ae, is 10 billion bits per second. Frame rate is based on the bit rate
and frame format definitions. Throughput, defined in IETF RFC 1242, is
the highest rate at which the system under test can forward the offered
load, without loss.

The frame rate for 10GbE is determined by a formula that divides the 10
billion bits per second by the preamble + frame length + inter-frame
gap.

The maximum frame rate is calculated using the minimum values of the
following parameters, as described in the IEEE 802 .3ae standard:

-  Preamble: 8 bytes \* 8 = 64 bits
-  Frame Length: 64 bytes (minimum) \* 8 = 512 bits
-  Inter-frame Gap: 12 bytes (minimum) \* 8 = 96 bits

Therefore, Maximum Frame Rate (64B Frames)
= MAC Transmit Bit Rate / (Preamble + Frame Length + Inter-frame Gap)
= 10,000,000,000 / (64 + 512 + 96)
= 10,000,000,000 / 672
= 14,880,952.38 frame per second (fps)

2.2.3.4.4 System isolation and validation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

A key consideration when conducting any sort of benchmark is trying to
ensure the consistency and repeatability of test results between runs.
When benchmarking the performance of a virtual switch there are many
factors that can affect the consistency of results. This section
describes these factors and the measures that can be taken to limit
their effects. In addition, this section will outline some system tests
to validate the platform and the VNF before conducting any vSwitch
benchmarking tests.

System Isolation
++++++++++++++++
When conducting a benchmarking test on any SUT, it is essential to limit
(and if reasonable, eliminate) any noise that may interfere with the
accuracy of the metrics collected by the test. This noise may be
introduced by other hardware or software (OS, other applications), and
can result in significantly varying performance metrics being collected
between consecutive runs of the same test. In the case of characterizing
the performance of a virtual switch, there are a number of configuration
parameters that can help increase the repeatability and stability of
test results, including:

-  OS/GRUB configuration:

   -  maxcpus = n where n >= 0; limits the kernel to using 'n'
      processors. Only use exactly what you need.
   -  isolcpus: Isolate CPUs from the general scheduler. Isolate all
      CPUs bar one which will be used by the OS.
   -  use taskset to affinitize the forwarding application and the VNFs
      onto isolated cores. VNFs and the vSwitch should be allocated
      their own cores, i.e. must not share the same cores. vCPUs for the
      VNF should be affinitized to individual cores also.
   -  Limit the amount of background applications that are running and
      set OS to boot to runlevel 3. Make sure to kill any unnecessary
      system processes/daemons.
   -  Only enable hardware that you need to use for your test – to
      ensure there are no other interrupts on the system.
   -  Configure NIC interrupts to only use the cores that are not
      allocated to any other process (VNF/vSwitch).

-  NUMA configuration: Any unused sockets in a multi-socket system
   should be disabled.
-  CPU pinning: The vSwitch and the VNF should each be affinitized to
   separate logical cores using a combination of maxcpus, isolcpus and
   taskset.
-  BIOS configuration: BIOS should be configured for performance where
   an explicit option exists, sleep states should be disabled, any
   virtualization optimization technologies should be enabled, and
   hyperthreading should also be enabled.

System Validation
+++++++++++++++++
System validation is broken down into two sub-categories: Platform
validation and VNF validation. The validation test itself involves
verifying the forwarding capability and stability for the sub-system
under test. The rationale behind system validation is two fold. Firstly
to give a tester confidence in the stability of the platform or VNF that
is being tested; and secondly to provide base performance comparison
points to understand the overhead introduced by the virtual switch.

* Benchmark platform forwarding capability: This is an OPTIONAL test
  used to verify the platform and measure the base performance (maximum
  forwarding rate in fps and latency) that can be achieved by the
  platform without a vSwitch or a VNF. The following diagram outlines
  the set-up for benchmarking Platform forwarding capability:

  .. code-block:: console

                                                            __
       +--------------------------------------------------+   |
       |   +------------------------------------------+   |   |
       |   |                                          |   |   |
       |   |          l2fw or DPDK L2FWD app          |   |  Host
       |   |                                          |   |   |
       |   +------------------------------------------+   |   |
       |   |                 NIC                      |   |   |
       +---+------------------------------------------+---+ __|
                  ^                           :
                  |                           |
                  :                           v
       +--------------------------------------------------+
       |                                                  |
       |                traffic generator                 |
       |                                                  |
       +--------------------------------------------------+

* Benchmark VNF forwarding capability: This test is used to verify
  the VNF and measure the base performance (maximum forwarding rate in
  fps and latency) that can be achieved by the VNF without a vSwitch.
  The performance metrics collected by this test will serve as a key
  comparison point for NIC passthrough technologies and vSwitches. VNF
  in this context refers to the hypervisor and the VM. The following
  diagram outlines the set-up for benchmarking VNF forwarding
  capability:

  .. code-block:: console

                                                            __
       +--------------------------------------------------+   |
       |   +------------------------------------------+   |   |
       |   |                                          |   |   |
       |   |                 VNF                      |   |   |
       |   |                                          |   |   |
       |   +------------------------------------------+   |   |
       |   |          Passthrough/SR-IOV              |   |  Host
       |   +------------------------------------------+   |   |
       |   |                 NIC                      |   |   |
       +---+------------------------------------------+---+ __|
                  ^                           :
                  |                           |
                  :                           v
       +--------------------------------------------------+
       |                                                  |
       |                traffic generator                 |
       |                                                  |
       +--------------------------------------------------+


Methodology to benchmark Platform/VNF forwarding capability
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

The recommended methodology for the platform/VNF validation and
benchmark is: - Run `RFC2889 <https://www.rfc-editor.org/rfc/rfc2289.txt>`__
Maximum Forwarding Rate test, this test will produce maximum
forwarding rate and latency results that will serve as the
expected values. These expected values can be used in
subsequent steps or compared with in subsequent validation tests. -
Transmit bidirectional traffic at line rate/max forwarding rate
(whichever is higher) for at least 72 hours, measure throughput (fps)
and latency. - Note: Traffic should be bidirectional. - Establish a
baseline forwarding rate for what the platform can achieve. - Additional
validation: After the test has completed for 72 hours run bidirectional
traffic at the maximum forwarding rate once more to see if the system is
still functional and measure throughput (fps) and latency. Compare the
measure the new obtained values with the expected values.

**NOTE 1**: How the Platform is configured for its forwarding capability
test (BIOS settings, GRUB configuration, runlevel...) is how the
platform should be configured for every test after this

**NOTE 2**: How the VNF is configured for its forwarding capability test
(# of vCPUs, vNICs, Memory, affinitization…) is how it should be
configured for every test that uses a VNF after this.

2.2.4 RFCs for testing virtual switch performance
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The starting point for defining the suite of tests for benchmarking the
performance of a virtual switch is to take existing RFCs and standards
that were designed to test their physical counterparts and adapting them
for testing virtual switches. The rationale behind this is to establish
a fair comparison between the performance of virtual and physical
switches. This section outlines the RFCs that are used by this
specification.

RFC 1242 Benchmarking Terminology for Network Interconnection
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Devices RFC 1242 defines the terminology that is used in describing
performance benchmarking tests and their results. Definitions and
discussions covered include: Back-to-back, bridge, bridge/router,
constant load, data link frame size, frame loss rate, inter frame gap,
latency, and many more.

RFC 2544 Benchmarking Methodology for Network Interconnect Devices
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 2544 outlines a benchmarking methodology for network Interconnect
Devices. The methodology results in performance metrics such as latency,
frame loss percentage, and maximum data throughput.

In this document network “throughput” (measured in millions of frames
per second) is based on RFC 2544, unless otherwise noted. Frame size
refers to Ethernet frames ranging from smallest frames of 64 bytes to
largest frames of 4K bytes.

Types of tests are:

1. Throughput test defines the maximum number of frames per second
   that can be transmitted without any error.

2. Latency test measures the time required for a frame to travel from
   the originating device through the network to the destination device.
   Please note that RFC2544 Latency measurement will be superseded with
   a measurement of average latency over all successfully transferred
   packets or frames.

3. Frame loss test measures the network’s
   response in overload conditions - a critical indicator of the
   network’s ability to support real-time applications in which a
   large amount of frame loss will rapidly degrade service quality.

4. Burst test assesses the buffering capability of a virtual switch. It
   measures the maximum number of frames received at full line rate
   before a frame is lost. In carrier Ethernet networks, this
   measurement validates the excess information rate (EIR) as defined in
   many SLAs.

5. System recovery to characterize speed of recovery from an overload
   condition.

6. Reset to characterize speed of recovery from device or software
   reset. This type of test has been updated by `RFC6201 <https://www.rfc-editor.org/rfc/rfc6201.txt>`__ as such,
   the methodology defined by this specification will be that of RFC 6201.

Although not included in the defined RFC 2544 standard, another crucial
measurement in Ethernet networking is packet delay variation. The
definition set out by this specification comes from
`RFC5481 <https://www.rfc-editor.org/rfc/rfc5481.txt>`__.

RFC 2285 Benchmarking Terminology for LAN Switching Devices
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 2285 defines the terminology that is used to describe the
terminology for benchmarking a LAN switching device. It extends RFC
1242 and defines: DUTs, SUTs, Traffic orientation and distribution,
bursts, loads, forwarding rates, etc.

RFC 2889 Benchmarking Methodology for LAN Switching
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 2889 outlines a benchmarking methodology for LAN switching, it
extends RFC 2544. The outlined methodology gathers performance
metrics for forwarding, congestion control, latency, address handling
and finally filtering.

RFC 3918 Methodology for IP Multicast Benchmarking
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 3918 outlines a methodology for IP Multicast benchmarking.

RFC 4737 Packet Reordering Metrics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 4737 describes metrics for identifying and counting re-ordered
packets within a stream, and metrics to measure the extent each
packet has been re-ordered.

RFC 5481 Packet Delay Variation Applicability Statement
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 5481 defined two common, but different forms of delay variation
metrics, and compares the metrics over a range of networking
circumstances and tasks. The most suitable form for vSwitch
benchmarking is the "PDV" form.

RFC 6201 Device Reset Characterization
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RFC 6201 extends the methodology for characterizing the speed of
recovery of the DUT from device or software reset described in RFC
2544.

2.2.5 Details of the Test Report
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There are a number of parameters related to the system, DUT and tests
that can affect the repeatability of a test results and should be
recorded. In order to minimise the variation in the results of a test,
it is recommended that the test report includes the following information:

-  Hardware details including:

   -  Platform details.
   -  Processor details.
   -  Memory information (see below)
   -  Number of enabled cores.
   -  Number of cores used for the test.
   -  Number of physical NICs, as well as their details (manufacturer,
      versions, type and the PCI slot they are plugged into).
   -  NIC interrupt configuration.
   -  BIOS version, release date and any configurations that were
      modified.

-  Software details including:

   -  OS version (for host and VNF)
   -  Kernel version (for host and VNF)
   -  GRUB boot parameters (for host and VNF).
   -  Hypervisor details (Type and version).
   -  Selected vSwitch, version number or commit id used.
   -  vSwitch launch command line if it has been parameterised.
   -  Memory allocation to the vSwitch – which NUMA node it is using,
      and how many memory channels.
   -  Where the vswitch is built from source: compiler details including
      versions and the flags that were used to compile the vSwitch.
   -  DPDK or any other SW dependency version number or commit id used.
   -  Memory allocation to a VM - if it's from Hugpages/elsewhere.
   -  VM storage type: snapshot/independent persistent/independent
      non-persistent.
   -  Number of VMs.
   -  Number of Virtual NICs (vNICs), versions, type and driver.
   -  Number of virtual CPUs and their core affinity on the host.
   -  Number vNIC interrupt configuration.
   -  Thread affinitization for the applications (including the vSwitch
      itself) on the host.
   -  Details of Resource isolation, such as CPUs designated for
      Host/Kernel (isolcpu) and CPUs designated for specific processes
      (taskset).

-  Memory Details

   -  Total memory
   -  Type of memory
   -  Used memory
   -  Active memory
   -  Inactive memory
   -  Free memory
   -  Buffer memory
   -  Swap cache
   -  Total swap
   -  Used swap
   -  Free swap

-  Test duration.
-  Number of flows.
-  Traffic Information:

   -  Traffic type - UDP, TCP, IMIX / Other.
   -  Packet Sizes.

-  Deployment Scenario.

**Note**: Tests that require additional parameters to be recorded will
explicitly specify this.

2.3. Test identification
------------------------
2.3.1 Throughput tests
~~~~~~~~~~~~~~~~~~~~~~
The following tests aim to determine the maximum forwarding rate that
can be achieved with a virtual switch. The list is not exhaustive but
should indicate the type of tests that should be required. It is
expected that more will be added.

Test ID: LTD.Throughput.RFC2544.PacketLossRatio
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 X% packet loss ratio Throughput and Latency Test

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    This test determines the DUT's maximum forwarding rate with X% traffic
    loss for a constant load (fixed length frames at a fixed interval time).
    The default loss percentages to be tested are: - X = 0% - X = 10^-7%

    Note: Other values can be tested if required by the user.

    The selected frame sizes are those previously defined under `Default
    Test Parameters <#DefaultParams>`__. The test can also be used to
    determine the average latency of the traffic.

    Under the `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__
    test methodology, the test duration will
    include a number of trials; each trial should run for a minimum period
    of 60 seconds. A binary search methodology must be applied for each
    trial to obtain the final result.

    **Expected Result**: At the end of each trial, the presence or absence
    of loss determines the modification of offered load for the next trial,
    converging on a maximum rate, or
    `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__ Throughput with X% loss.
    The Throughput load is re-used in related
    `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__ tests and other
    tests.

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The maximum forwarding rate in Frames Per Second (FPS) and Mbps of
       the DUT for each frame size with X% packet loss.
    -  The average latency of the traffic flow when passing through the DUT
       (if testing for latency, note that this average is different from the
       test specified in Section 26.3 of
       `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__).
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

Test ID: LTD.Throughput.RFC2544.PacketLossRatioFrameModification
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 X% packet loss Throughput and Latency Test with
    packet modification

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    This test determines the DUT's maximum forwarding rate with X% traffic
    loss for a constant load (fixed length frames at a fixed interval time).
    The default loss percentages to be tested are: - X = 0% - X = 10^-7%

    Note: Other values can be tested if required by the user.

    The selected frame sizes are those previously defined under `Default
    Test Parameters <#DefaultParams>`__. The test can also be used to
    determine the average latency of the traffic.

    Under the `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__
    test methodology, the test duration will
    include a number of trials; each trial should run for a minimum period
    of 60 seconds. A binary search methodology must be applied for each
    trial to obtain the final result.

    During this test, the DUT must perform the following operations on the
    traffic flow:

    -  Perform packet parsing on the DUT's ingress port.
    -  Perform any relevant address look-ups on the DUT's ingress ports.
    -  Modify the packet header before forwarding the packet to the DUT's
       egress port. Packet modifications include:

       -  Modifying the Ethernet source or destination MAC address.
       -  Modifying/adding a VLAN tag. (**Recommended**).
       -  Modifying/adding a MPLS tag.
       -  Modifying the source or destination ip address.
       -  Modifying the TOS/DSCP field.
       -  Modifying the source or destination ports for UDP/TCP/SCTP.
       -  Modifying the TTL.

    **Expected Result**: The Packet parsing/modifications require some
    additional degree of processing resource, therefore the
    `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__
    Throughput is expected to be somewhat lower than the Throughput level
    measured without additional steps. The reduction is expected to be
    greatest on tests with the smallest packet sizes (greatest header
    processing rates).

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The maximum forwarding rate in Frames Per Second (FPS) and Mbps of
       the DUT for each frame size with X% packet loss and packet
       modification operations being performed by the DUT.
    -  The average latency of the traffic flow when passing through the DUT
       (if testing for latency, note that this average is different from the
       test specified in Section 26.3 of
       `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__).
    -  The `RFC5481 <https://www.rfc-editor.org/rfc/rfc5481.txt>`__
       PDV form of delay variation on the traffic flow,
       using the 99th percentile.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

Test ID: LTD.Throughput.RFC2544.Profile
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 Throughput and Latency Profile

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    This test reveals how throughput and latency degrades as the offered
    rate varies in the region of the DUT's maximum forwarding rate as
    determined by LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss).
    For example it can be used to determine if the degradation of throughput
    and latency as the offered rate increases is slow and graceful or sudden
    and severe.

    The selected frame sizes are those previously defined under `Default
    Test Parameters <#DefaultParams>`__.

    The offered traffic rate is described as a percentage delta with respect
    to the DUT's RFC 2544 Throughput as determined by
    LTD.Throughput.RFC2544.PacketLoss Ratio (0% Packet Loss case). A delta
    of 0% is equivalent to an offered traffic rate equal to the RFC 2544
    Throughput; A delta of +50% indicates an offered rate half-way
    between the Throughput and line-rate, whereas a delta of
    -50% indicates an offered rate of half the maximum rate. Therefore the
    range of the delta figure is natuarlly bounded at -100% (zero offered
    traffic) and +100% (traffic offered at line rate).

    The following deltas to the maximum forwarding rate should be applied:

    -  -50%, -10%, 0%, +10% & +50%

    **Expected Result**: For each packet size a profile should be produced
    of how throughput and latency vary with offered rate.

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The forwarding rate in Frames Per Second (FPS) and Mbps of the DUT
       for each delta to the maximum forwarding rate and for each frame
       size.
    -  The average latency for each delta to the maximum forwarding rate and
       for each frame size.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.
    -  Any failures experienced (for example if the vSwitch crashes, stops
       processing packets, restarts or becomes unresponsive to commands)
       when the offered load is above Maximum Throughput MUST be recorded
       and reported with the results.

Test ID: LTD.Throughput.RFC2544.SystemRecoveryTime
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 System Recovery Time Test

    **Prerequisite Test** LTD.Throughput.RFC2544.PacketLossRatio

    **Priority**:

    **Description**:

    The aim of this test is to determine the length of time it takes the DUT
    to recover from an overload condition for a constant load (fixed length
    frames at a fixed interval time). The selected frame sizes are those
    previously defined under `Default Test Parameters <#DefaultParams>`__,
    traffic should be sent to the DUT under normal conditions. During the
    duration of the test and while the traffic flows are passing though the
    DUT, at least one situation leading to an overload condition for the DUT
    should occur. The time from the end of the overload condition to when
    the DUT returns to normal operations should be measured to determine
    recovery time. Prior to overloading the DUT, one should record the
    average latency for 10,000 packets forwarded through the DUT.

    The overload condition SHOULD be to transmit traffic at a very high
    frame rate to the DUT (150% of the maximum 0% packet loss rate as
    determined by LTD.Throughput.RFC2544.PacketLossRatio or line-rate
    whichever is lower), for at least 60 seconds, then reduce the frame rate
    to 75% of the maximum 0% packet loss rate. A number of time-stamps
    should be recorded: - Record the time-stamp at which the frame rate was
    reduced and record a second time-stamp at the time of the last frame
    lost. The recovery time is the difference between the two timestamps. -
    Record the average latency for 10,000 frames after the last frame loss
    and continue to record average latency measurements for every 10,000
    frames, when latency returns to within 10% of pre-overload levels record
    the time-stamp.

    **Expected Result**:

    **Metrics collected**

    The following are the metrics collected for this test:

    -  The length of time it takes the DUT to recover from an overload
       condition.
    -  The length of time it takes the DUT to recover the average latency to
       pre-overload conditions.

    **Deployment scenario**:

    -  Physical → virtual switch → physical.

Test ID: LTD.Throughput.RFC2544.BackToBackFrames
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2544 Back To Back Frames Test

    **Prerequisite Test**: N

    **Priority**:

    **Description**:

    The aim of this test is to characterize the ability of the DUT to
    process back-to-back frames. For each frame size previously defined
    under `Default Test Parameters <#DefaultParams>`__, a burst of traffic
    is sent to the DUT with the minimum inter-frame gap between each frame.
    If the number of received frames equals the number of frames that were
    transmitted, the burst size should be increased and traffic is sent to
    the DUT again. The value measured is the back-to-back value, that is the
    maximum burst size the DUT can handle without any frame loss.

    **Expected Result**:

    Tests of back-to-back frames with physical devices have produced
    unstable results in some cases. All tests should be repeated in multiple
    test sessions and results stability should be examined.

    **Metrics collected**

    The following are the metrics collected for this test:

    -  The back-to-back value, which is the the number of frames in the
       longest burst that the DUT will handle without the loss of any
       frames.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

    **Deployment scenario**:

    -  Physical → virtual switch → physical.

Test ID: LTD.Throughput.RFC2889.MaxForwardingRateSoak
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2889 X% packet loss Max Forwarding Rate Soak Test

    **Prerequisite Test** LTD.Throughput.RFC2544.PacketLossRatio

    **Priority**:

    **Description**:

    The aim of this test is to understand the Max Forwarding Rate stability
    over an extended test duration in order to uncover any outliers. To allow
    for an extended test duration, the test should ideally run for 24 hours
    or, if this is not possible, for at least 6 hours. For this test, each frame
    size must be sent at the highest Throughput rate with X% packet loss, as
    determined in the prerequisite test. The default loss percentages to be
    tested are: - X = 0% - X = 10^-7%

    Note: Other values can be tested if required by the user.

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  Max Forwarding Rate stability of the DUT.

       -  This means reporting the number of packets lost per time interval
          and reporting any time intervals with packet loss. The
          `RFC2889 <https://www.rfc-editor.org/rfc/rfc2289.txt>`__
          Forwarding Rate shall be measured in each interval.
          An interval of 60s is suggested.

    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.
    -  The `RFC5481 <https://www.rfc-editor.org/rfc/rfc5481.txt>`__
       PDV form of delay variation on the traffic flow,
       using the 99th percentile.

Test ID: LTD.Throughput.RFC2889.MaxForwardingRateSoakFrameModification
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2889 Max Forwarding Rate Soak Test with Frame Modification

    **Prerequisite Test**: LTD.Throughput.RFC2544.PacketLossRatioFrameModification (0% Packet Loss)

    **Priority**:

    **Description**:

    The aim of this test is to understand the Max Forwarding Rate stability over an
    extended test duration in order to uncover any outliers. To allow for an
    extended test duration, the test should ideally run for 24 hours or, if
    this is not possible, for at least 6 hour. For this test, each frame
    size must be sent at the highest Throughput rate with 0% packet loss, as
    determined in the prerequisite test.

    During this test, the DUT must perform the following operations on the
    traffic flow:

    -  Perform packet parsing on the DUT's ingress port.
    -  Perform any relevant address look-ups on the DUT's ingress ports.
    -  Modify the packet header before forwarding the packet to the DUT's
       egress port. Packet modifications include:

       -  Modifying the Ethernet source or destination MAC address.
       -  Modifying/adding a VLAN tag (**Recommended**).
       -  Modifying/adding a MPLS tag.
       -  Modifying the source or destination ip address.
       -  Modifying the TOS/DSCP field.
       -  Modifying the source or destination ports for UDP/TCP/SCTP.
       -  Modifying the TTL.

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  Max Forwarding Rate stability of the DUT.

       -  This means reporting the number of packets lost per time interval
          and reporting any time intervals with packet loss. The
          `RFC2889 <https://www.rfc-editor.org/rfc/rfc2289.txt>`__
          Forwarding Rate shall be measured in each interval.
          An interval of 60s is suggested.

    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.
    -  The `RFC5481 <https://www.rfc-editor.org/rfc/rfc5481.txt>`__ PDV form of delay variation on the traffic flow,
       using the 99th percentile.

Test ID: LTD.Throughput.RFC6201.ResetTime
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 6201 Reset Time Test

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    The aim of this test is to determine the length of time it takes the DUT
    to recover from a reset.

    Two reset methods are defined - planned and unplanned. A planned reset
    requires stopping and restarting the virtual switch by the usual
    'graceful' method defined by it's documentation. An unplanned reset
    requires simulating a fatal internal fault in the virtual switch - for
    example by using kill -SIGKILL on a Linux environment.

    Both reset methods SHOULD be exercised.

    For each frame size previously defined under `Default Test
    Parameters <#DefaultParams>`__, traffic should be sent to the DUT under
    normal conditions. During the duration of the test and while the traffic
    flows are passing through the DUT, the DUT should be reset and the Reset
    time measured. The Reset time is the total time that a device is
    determined to be out of operation and includes the time to perform the
    reset and the time to recover from it (cf. `RFC6201 <https://www.rfc-editor.org/rfc/rfc6201.txt>`__).

    `RFC6201 <https://www.rfc-editor.org/rfc/rfc6201.txt>`__ defines two methods to measure the Reset time:
      - Frame-Loss Method: which requires the monitoring of the number of
        lost frames and calculates the Reset time based on the number of
        frames lost and the offered rate according to the following
        formula:

        .. code-block:: console

                                    Frames_lost (packets)
                 Reset_time = -------------------------------------
                                Offered_rate (packets per second)

      - Timestamp Method: which measures the time from which the last frame
        is forwarded from the DUT to the time the first frame is forwarded
        after the reset. This involves time-stamping all transmitted frames
        and recording the timestamp of the last frame that was received prior
        to the reset and also measuring the timestamp of the first frame that
        is received after the reset. The Reset time is the difference between
        these two timestamps.

    According to `RFC6201 <https://www.rfc-editor.org/rfc/rfc6201.txt>`__ the choice of method depends on the test
    tool's capability; the Frame-Loss method SHOULD be used if the test tool
    supports: - Counting the number of lost frames per stream. -
    Transmitting test frame despite the physical link status.

    whereas the Timestamp method SHOULD be used if the test tool supports: -
    Timestamping each frame. - Monitoring received frame's timestamp. -
    Transmitting frames only if the physical link status is up.

    **Expected Result**:

    **Metrics collected**

    The following are the metrics collected for this test: - Average Reset
    Time over the number of trials performed.

    Results of this test should include the following information: - The
    reset method used. - Throughput in Fps and Mbps. - Average Frame Loss
    over the number of trials performed. - Average Reset Time in
    milliseconds over the number of trials performed. - Number of trials
    performed. - Protocol: IPv4, IPv6, MPLS, etc. - Frame Size in Octets -
    Port Media: Ethernet, Gigabit Ethernet (GbE), etc. - Port Speed: 10
    Gbps, 40 Gbps etc. - Interface Encapsulation: Ethernet, Ethernet VLAN,
    etc.

    **Deployment scenario**:

    -  Physical → virtual switch → physical.

Test ID: LTD.Throughput.RFC2889.MaxForwardingRate
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2889 Forwarding Rate Test

    **Prerequisite Test**: LTD.Throughput.RFC2544.PacketLossRatio

    **Priority**:

    **Description**:

    This test measures the DUT's Max Forwarding Rate when the Offered Load
    is varied between the throughput and the Maximum Offered Load for fixed
    length frames at a fixed time interval. The selected frame sizes are
    those previously defined under `Default Test
    Parameters <#DefaultParams>`__. The throughput is the maximum offered
    load with 0% frame loss (measured by the prerequisite test), and the
    Maximum Offered Load (as defined by
    `RFC2285 <https://www.rfc-editor.org/rfc/rfc2285.txt>`__) is *"the highest
    number of frames per second that an external source can transmit to a
    DUT/SUT for forwarding to a specified output interface or interfaces"*.

    Traffic should be sent to the DUT at a particular rate (TX rate)
    starting with TX rate equal to the throughput rate. The rate of
    successfully received frames at the destination counted (in FPS). If the
    RX rate is equal to the TX rate, the TX rate should be increased by a
    fixed step size and the RX rate measured again until the Max Forwarding
    Rate is found.

    The trial duration for each iteration should last for the period of time
    needed for the system to reach steady state for the frame size being
    tested. Under `RFC2889 <https://www.rfc-editor.org/rfc/rfc2289.txt>`__
    (Sec. 5.6.3.1) test methodology, the test
    duration should run for a minimum period of 30 seconds, regardless
    whether the system reaches steady state before the minimum duration
    ends.

    **Expected Result**: According to
    `RFC2889 <https://www.rfc-editor.org/rfc/rfc2289.txt>`__ The Max Forwarding Rate
    is the highest forwarding rate of a DUT taken from an iterative set of
    forwarding rate measurements. The iterative set of forwarding rate
    measurements are made by setting the intended load transmitted from an
    external source and measuring the offered load (i.e what the DUT is
    capable of forwarding). If the Throughput == the Maximum Offered Load,
    it follows that Max Forwarding Rate is equal to the Maximum Offered
    Load.

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The Max Forwarding Rate for the DUT for each packet size.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

    **Deployment scenario**:

    -  Physical → virtual switch → physical. Note: Full mesh tests with
       multiple ingress and egress ports are a key aspect of RFC 2889
       benchmarks, and scenarios with both 2 and 4 ports should be tested.
       In any case, the number of ports used must be reported.


Test ID: LTD.Throughput.RFC2889.ForwardPressure
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2889 Forward Pressure Test

    **Prerequisite Test**: LTD.Throughput.RFC2889.MaxForwardingRate

    **Priority**:

    **Description**:

    The aim of this test is to determine if the DUT transmits frames with an
    inter-frame gap that is less than 12 bytes. This test overloads the DUT
    and measures the output for forward pressure. Traffic should be
    transmitted to the DUT with an inter-frame gap of 11 bytes, this will
    overload the DUT by 1 byte per frame. The forwarding rate of the DUT
    should be measured.

    **Expected Result**: The forwarding rate should not exceed the maximum
    forwarding rate of the DUT collected by
    LTD.Throughput.RFC2889.MaxForwardingRate.

    **Metrics collected**

    The following are the metrics collected for this test:

    -  Forwarding rate of the DUT in FPS or Mbps.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

    **Deployment scenario**:

    -  Physical → virtual switch → physical.


Test ID: LTD.Throughput.RFC2889.ErrorFramesFiltering
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2889 Error Frames Filtering Test

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    The aim of this test is to determine whether the DUT will propagate any
    erroneous frames it receives or whether it is capable of filtering out
    the erroneous frames. Traffic should be sent with erroneous frames
    included within the flow at random intervals. Illegal frames that must
    be tested include: - Oversize Frames. - Undersize Frames. - CRC Errored
    Frames. - Dribble Bit Errored Frames - Alignment Errored Frames

    The traffic flow exiting the DUT should be recorded and checked to
    determine if the erroneous frames where passed through the DUT.

    **Expected Result**: Broken frames are not passed!

    **Metrics collected**

    No Metrics are collected in this test, instead it determines:

    -  Whether the DUT will propagate erroneous frames.
    -  Or whether the DUT will correctly filter out any erroneous frames
       from traffic flow with out removing correct frames.

    **Deployment scenario**:

    -  Physical → virtual switch → physical.

Test ID: LTD.Throughput.RFC2889.BroadcastFrameForwarding
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2889 Broadcast Frame Forwarding Test

    **Prerequisite Test**: N

    **Priority**:

    **Description**:

    The aim of this test is to determine the maximum forwarding rate of the
    DUT when forwarding broadcast traffic. For each frame previously defined
    under `Default Test Parameters <#DefaultParams>`__, the traffic should
    be set up as broadcast traffic. The traffic throughput of the DUT should
    be measured.

    The test should be conducted with at least 4 physical ports on the DUT.
    The number of ports used MUST be recorded.

    As broadcast involves forwarding a single incoming packet to several
    destinations, the latency of a single packet is defined as the average
    of the latencies for each of the broadcast destinations.

    The incoming packet is transmitted on each of the other physical ports,
    it is not transmitted on the port on which it was received. The test MAY
    be conducted using different broadcasting ports to uncover any
    performance differences.

    **Expected Result**:

    **Metrics collected**:

    The following are the metrics collected for this test:

    -  The forwarding rate of the DUT when forwarding broadcast traffic.
    -  The minimum, average & maximum packets latencies observed.

    **Deployment scenario**:

    -  Physical → virtual switch 3x physical. In the Broadcast rate testing,
    four test ports are required. One of the ports is connected to the test
    device, so it can send broadcast frames and listen for miss-routed frames.

2.3.2 Packet Latency tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~
These tests will measure the store and forward latency as well as the packet
delay variation for various packet types through the virtual switch. The
following list is not exhaustive but should indicate the type of tests
that should be required. It is expected that more will be added.

Test ID: LTD.PacketLatency.InitialPacketProcessingLatency
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: Initial Packet Processing Latency

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    In some virtual switch architectures, the first packets of a flow will
    take the system longer to process than subsequent packets in the flow.
    This test determines the latency for these packets. The test will
    measure the latency of the packets as they are processed by the
    flow-setup-path of the DUT. There are two methods for this test, a
    recommended method and a nalternative method that can be used if it is
    possible to disable the fastpath of the virtual switch.

    Recommended method: This test will send 64,000 packets to the DUT, each
    belonging to a different flow. Average packet latency will be determined
    over the 64,000 packets.

    Alternative method: This test will send a single packet to the DUT after
    a fixed interval of time. The time interval will be equivalent to the
    amount of time it takes for a flow to time out in the virtual switch
    plus 10%. Average packet latency will be determined over 1,000,000
    packets.

    This test is intended only for non-learning virtual switches; For learning
    virtual switches use RFC2889.

    For this test, only unidirectional traffic is required.

    **Expected Result**: The average latency for the initial packet of all
    flows should be greater than the latency of subsequent traffic.

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  Average latency of the initial packets of all flows that are
       processed by the DUT.

    **Deployment scenario**:

    -  Physical → Virtual Switch → Physical.

Test ID: LTD.PacketDelayVariation.RFC3393.Soak
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: Packet Delay Variation Soak Test

    **Prerequisite Tests**: LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss)

    **Priority**:

    **Description**:

    The aim of this test is to understand the distribution of packet delay
    variation for different frame sizes over an extended test duration and
    to determine if there are any outliers. To allow for an extended test
    duration, the test should ideally run for 24 hours or, if this is not
    possible, for at least 6 hour. For this test, each frame size must be
    sent at the highest possible throughput with 0% packet loss, as
    determined in the prerequisite test.

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The packet delay variation value for traffic passing through the DUT.
    -  The `RFC5481 <https://www.rfc-editor.org/rfc/rfc5481.txt>`__
       PDV form of delay variation on the traffic flow,
       using the 99th percentile, for each 60s interval during the test.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

2.3.3 Scalability tests
~~~~~~~~~~~~~~~~~~~~~~~~
The general aim of these tests is to understand the impact of large flow
table size and flow lookups on throughput. The following list is not
exhaustive but should indicate the type of tests that should be required.
It is expected that more will be added.

Test ID: LTD.Scalability.RFC2544.0PacketLoss
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 0% loss Scalability throughput test

    **Prerequisite Test**: LTD.Throughput.RFC2544.PacketLossRatio, IF the
    delta Throughput between the single-flow RFC2544 test and this test with
    a variable number of flows is desired.

    **Priority**:

    **Description**:

    The aim of this test is to measure how throughput changes as the number
    of flows in the DUT increases. The test will measure the throughput
    through the fastpath, as such the flows need to be installed on the DUT
    before passing traffic.

    For each frame size previously defined under `Default Test
    Parameters <#DefaultParams>`__ and for each of the following number of
    flows:

    -  1,000
    -  2,000
    -  4,000
    -  8,000
    -  16,000
    -  32,000
    -  64,000
    -  Max supported number of flows.

    This test will be conducted under two conditions following the
    establishment of all flows as required by RFC 2544, regarding the flow
    expiration time-out:

    1) The time-out never expires during each trial.

    2) The time-out expires for all flows periodically. This would require a
    short time-out compared with flow re-appearance for a small number of
    flows, and may not be possible for all flow conditions.

    The maximum 0% packet loss Throughput should be determined in a manner
    identical to LTD.Throughput.RFC2544.PacketLossRatio.

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The maximum number of frames per second that can be forwarded at the
       specified number of flows and the specified frame size, with zero
       packet loss.

Test ID: LTD.MemoryBandwidth.RFC2544.0PacketLoss.Scalability
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 0% loss Memory Bandwidth Scalability test

    **Prerequisite Tests**: LTD.Throughput.RFC2544.PacketLossRatio, IF the
    delta Throughput between an undisturbed RFC2544 test and this test with
    the Throughput affected by cache and memory bandwidth contention is desired.

    **Priority**:

    **Description**:

    The aim of this test is to understand how the DUT's performance is
    affected by cache sharing and memory bandwidth between processes.

    During the test all cores not used by the vSwitch should be running a
    memory intensive application. This application should read and write
    random data to random addresses in unused physical memory. The random
    nature of the data and addresses is intended to consume cache, exercise
    main memory access (as opposed to cache) and exercise all memory buses
    equally. Furthermore:

    - the ratio of reads to writes should be recorded. A ratio of 1:1
      SHOULD be used.
    - the reads and writes MUST be of cache-line size and be cache-line aligned.
    - in NUMA architectures memory access SHOULD be local to the core's node.
      Whether only local memory or a mix of local and remote memory is used
      MUST be recorded.
    - the memory bandwidth (reads plus writes) used per-core MUST be recorded;
      the test MUST be run with a per-core memory bandwidth equal to half the
      maximum system memory bandwidth divided by the number of cores. The test
      MAY be run with other values for the per-core memory bandwidth.
    - the test MAY also be run with the memory intensive application running
      on all cores.

    Under these conditions the DUT's 0% packet loss throughput is determined
    as per LTD.Throughput.RFC2544.PacketLossRatio.

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The DUT's 0% packet loss throughput in the presence of cache sharing and memory bandwidth between processes.

2.3.4 Activation tests
~~~~~~~~~~~~~~~~~~~~~~~~
The general aim of these tests is to understand the capacity of the
and speed with which the vswitch can accomodate new flows.

Test ID: LTD.Activation.RFC2889.AddressCachingCapacity
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2889 Address Caching Capacity Test

    **Prerequisite Test**: N/A

    **Priority**:

    **Description**:

    Please note this test is only applicable to virtual switches that are capable of
    MAC learning. The aim of this test is to determine the address caching
    capacity of the DUT for a constant load (fixed length frames at a fixed
    interval time). The selected frame sizes are those previously defined
    under `Default Test Parameters <#DefaultParams>`__.

    In order to run this test the aging time, that is the maximum time the
    DUT will keep a learned address in its flow table, and a set of initial
    addresses, whose value should be >= 1 and <= the max number supported by
    the implementation must be known. Please note that if the aging time is
    configurable it must be longer than the time necessary to produce frames
    from the external source at the specified rate. If the aging time is
    fixed the frame rate must be brought down to a value that the external
    source can produce in a time that is less than the aging time.

    Learning Frames should be sent from an external source to the DUT to
    install a number of flows. The Learning Frames must have a fixed
    destination address and must vary the source address of the frames. The
    DUT should install flows in its flow table based on the varying source
    addresses. Frames should then be transmitted from an external source at
    a suitable frame rate to see if the DUT has properly learned all of the
    addresses. If there is no frame loss and no flooding, the number of
    addresses sent to the DUT should be increased and the test is repeated
    until the max number of cached addresses supported by the DUT
    determined.

    **Expected Result**:

    **Metrics collected**:

    The following are the metrics collected for this test:

    -  Number of cached addresses supported by the DUT.
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

    **Deployment scenario**:

    -  Physical → virtual switch → 2 x physical (one receiving, one listening).

Test ID: LTD.Activation.RFC2889.AddressLearningRate
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC2889 Address Learning Rate Test

    **Prerequisite Test**: LTD.Memory.RFC2889.AddressCachingCapacity

    **Priority**:

    **Description**:

    Please note this test is only applicable to virtual switches that are capable of
    MAC learning. The aim of this test is to determine the rate of address
    learning of the DUT for a constant load (fixed length frames at a fixed
    interval time). The selected frame sizes are those previously defined
    under `Default Test Parameters <#DefaultParams>`__, traffic should be
    sent with each IPv4/IPv6 address incremented by one. The rate at which
    the DUT learns a new address should be measured. The maximum caching
    capacity from LTD.Memory.RFC2889.AddressCachingCapacity should be taken
    into consideration as the maximum number of addresses for which the
    learning rate can be obtained.

    **Expected Result**: It may be worthwhile to report the behaviour when
    operating beyond address capacity - some DUTs may be more friendly to
    new addresses than others.

    **Metrics collected**:

    The following are the metrics collected for this test:

    -  The address learning rate of the DUT.

    **Deployment scenario**:

    -  Physical → virtual switch → 2 x physical (one receiving, one listening).


2.3.5 Coupling between control path and datapath Tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following tests aim to determine how tightly coupled the datapath
and the control path are within a virtual switch. The following list
is not exhaustive but should indicate the type of tests that should be
required. It is expected that more will be added.

Test ID: LTD.CPDPCouplingFlowAddition
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: Control Path and Datapath Coupling

    **Prerequisite Test**:

    **Priority**:

    **Description**:

    The aim of this test is to understand how exercising the DUT's control
    path affects datapath performance.

    Initially a certain number of flow table entries are installed in the
    vSwitch. Then over the duration of an RFC2544 throughput test
    flow-entries are added and removed at the rates specified below. No
    traffic is 'hitting' these flow-entries, they are simply added and
    removed.

    The test MUST be repeated with the following initial number of
    flow-entries installed: - < 10 - 1000 - 100,000 - 10,000,000 (or the
    maximum supported number of flow-entries)

    The test MUST be repeated with the following rates of flow-entry
    addition and deletion per second: - 0 - 1 (i.e. 1 addition plus 1
    deletion) - 100 - 10,000

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  The maximum forwarding rate in Frames Per Second (FPS) and Mbps of
       the DUT.
    -  The average latency of the traffic flow when passing through the DUT
       (if testing for latency, note that this average is different from the
       test specified in Section 26.3 of
       `RFC2544 <https://www.rfc-editor.org/rfc/rfc2544.txt>`__).
    -  CPU and memory utilization may also be collected as part of this
       test, to determine the vSwitch's performance footprint on the system.

    **Deployment scenario**:

    -  Physical → virtual switch → physical.

2.3.6 CPU and memory consumption
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following tests will profile a virtual switch's CPU and memory
utilization under various loads and circumstances. The following
list is not exhaustive but should indicate the type of tests that
should be required. It is expected that more will be added.

Test ID: LTD.CPU.RFC2544.0PacketLoss
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    **Title**: RFC 2544 0% Loss Compute Test

    **Prerequisite Test**:

    **Priority**:

    **Description**:

    The aim of this test is to understand the overall performance of the
    system when a CPU intensive application is run on the same DUT as the
    Virtual Switch. For each frame size, an
    LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss) test should be
    performed. Throughout the entire test a CPU intensive application should
    be run on all cores on the system not in use by the Virtual Switch. For
    NUMA system only cores on the same NUMA node are loaded.

    It is recommended that stress-ng be used for loading the non-Virtual
    Switch cores but any stress tool MAY be used.

    **Expected Result**:

    **Metrics Collected**:

    The following are the metrics collected for this test:

    -  CPU utilization of the cores running the Virtual Switch.
    -  The number of identity of the cores allocated to the Virtual Switch.
    -  The configuration of the stress tool (for example the command line
       parameters used to start it.)

2.3.7 Summary List of Tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~
1. Throughput tests

  - Test ID: LTD.Throughput.RFC2544.PacketLossRatio
  - Test ID: LTD.Throughput.RFC2544.PacketLossRatioFrameModification
  - Test ID: LTD.Throughput.RFC2544.Profile
  - Test ID: LTD.Throughput.RFC2544.SystemRecoveryTime
  - Test ID: LTD.Throughput.RFC2544.BackToBackFrames
  - Test ID: LTD.Throughput.RFC2889.Soak
  - Test ID: LTD.Throughput.RFC2889.SoakFrameModification
  - Test ID: LTD.Throughput.RFC6201.ResetTime
  - Test ID: LTD.Throughput.RFC2889.MaxForwardingRate
  - Test ID: LTD.Throughput.RFC2889.ForwardPressure
  - Test ID: LTD.Throughput.RFC2889.ErrorFramesFiltering
  - Test ID: LTD.Throughput.RFC2889.BroadcastFrameForwarding

2. Packet Latency tests

  - Test ID: LTD.PacketLatency.InitialPacketProcessingLatency
  - Test ID: LTD.PacketDelayVariation.RFC3393.Soak

3. Scalability tests

  - Test ID: LTD.Scalability.RFC2544.0PacketLoss
  - Test ID: LTD.MemoryBandwidth.RFC2544.0PacketLoss.Scalability

4. Acivation tests

  - Test ID: LTD.Activation.RFC2889.AddressCachingCapacity
  - Test ID: LTD.Activation.RFC2889.AddressLearningRate

5. Coupling between control path and datapath Tests

  - Test ID: LTD.CPDPCouplingFlowAddition

6. CPU and memory consumption

  - Test ID: LTD.CPU.RFC2544.0PacketLoss