Network Working Group M. Tahhan
Internet-Draft B. O'Mahony
Intended status: Informational Intel
Expires: December 10, 2017 A. Morton
AT&T Labs
June 8, 2017

Benchmarking Virtual Switches in OPNFV
draft-ietf-bmwg-vswitch-opnfv-04

Abstract

This memo describes the contributions of the Open Platform for NFV (OPNFV) project on virtual switch performance "VSPERF", particularly in the areas of test set-ups and configuration parameters for the system under test. This project has extended the current and completed work of the Benchmarking Methodology Working Group in IETF, and references existing literature. The Benchmarking Methodology Working Group has traditionally conducted laboratory characterization of dedicated physical implementations of internetworking functions. Therefore, this memo describes the additional considerations when virtual switches are implemented in general-purpose hardware. The expanded tests and benchmarks are also influenced by the OPNFV mission to support virtualization of the "telco" infrastructure.

Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on December 10, 2017.

Copyright Notice

Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.


Table of Contents

1. Introduction

Benchmarking Methodology Working Group (BMWG) has traditionally conducted laboratory characterization of dedicated physical implementations of internetworking functions. The Black-box Benchmarks of Throughput, Latency, Forwarding Rates and others have served our industry for many years. Now, Network Function Virtualization (NFV) has the goal to transform how internetwork functions are implemented, and therefore has garnered much attention.

A virtual switch (vswitch) is an important aspect of the NFV infrastructure; it provides connectivity between and among physical network functions and virtual network functions. As a result, there are many vswitch benchmarking efforts, but few specifications to guide the many new test design choices. This is a complex problem and an industry-wide work-in-progress. In future, several of BMWG's fundamental specifications will likely be updated as more testing experience helps to form consensus around new methodologies, and BMWG should continue to collaborate with all organizations who share the same goal.

This memo describes the contributions of the Open Platform for NFV (OPNFV) project on virtual switch performance characterization, "VSPERF", through the Danube 3.0 (fourth) release [DanubeRel] to the chartered work of the BMWG (with stable references to their test descriptions). This project has extended the current and completed work of the BMWG in IETF, and references existing literature. For example, the most often referenced RFC is [RFC2544] (which depends on [RFC1242]), so the foundation of the benchmarking work in OPNFV is common and strong. The recommended extensions are specifically in the areas of test set-ups and configuration parameters for the system under test.

See [VSPERFhome] for more background, and the OPNFV website for general information [OPNFV].

The authors note that OPNFV distinguishes itself from other open source compute and networking projects through its emphasis on existing "telco" services as opposed to cloud-computing. There are many ways in which telco requirements have different emphasis on performance dimensions when compared to cloud computing: support for and transfer of isochronous media streams is one example.

1.1. Abbreviations

ACK Acknowledge
ACPI Advanced Configuration and Power Interface
BIOS Basic Input Output System
BMWG Benchmarking Methodology Working Group
CPDP Control Plane Data Plane
CPU Central Processing Unit
DIMM Dual In-line Memory Module
DPDK Data Plane Development Kit
DUT Device Under Test
GRUB Grand Unified Bootloader
ID Identification
IMIX Internet Mix
IP Internet Protocol
IPPM IP Performance Metrics 
LAN Local Area Network
LTD Level Test Design 
NFV Network Functions Virtualisation
NIC Network Interface Card
NUMA Non Uniform Memory Access
OPNFV Open Platform for NFV
OS Operating System
PCI Peripheral Component Interconnect
PDV Packet Delay Variation
SR/IOV Single Root/Input Output Virtualization
SUT System Under Test
SW Software
TCP Transmission control Protocol
TSO TCP Segment Offload
UDP User Datagram Protocol
VM Virtual Machine
VNF Virtualised Network Function
VSPERF OPNFV vSwitch Performance Project

For the purposes of this document, the following abbreviations apply:

2. Scope

The primary purpose and scope of the memo is to describe key aspects of vswitch benchmarking, particularly in the areas of test set-ups and configuration parameters for the system under test, and extend the body of extensive BMWG literature and experience. Initial feedback indicates that many of these extensions may be applicable beyond this memo's current scope (to hardware switches in the NFV Infrastructure and to virtual routers, for example). Additionally, this memo serves as a vehicle to include more detail and relevant commentary from BMWG and other Open Source communities, under BMWG's chartered work to characterize the NFV Infrastructure.

The benchmarking covered in this memo should be applicable to many types of vswitches, and remain vswitch-agnostic to great degree. There has been no attempt to track and test all features of any specific vswitch implementation.

3. Benchmarking Considerations

This section highlights some specific considerations (from [I-D.ietf-bmwg-virtual-net])related to Benchmarks for virtual switches. The OPNFV project is sharing its present view on these areas, as they develop their specifications in the Level Test Design (LTD) document.

3.1. Comparison with Physical Network Functions

To compare the performance of virtual designs and implementations with their physical counterparts, identical benchmarks are needed. BMWG has developed specifications for many physical network functions. The BMWG has recommended to re-use existing benchmarks and methods in [I-D.ietf-bmwg-virtual-net], and the OPNFV LTD expands on them as described here. A key configuration aspect for vswitches is the number of parallel CPU cores required to achieve comparable performance with a given physical device, or whether some limit of scale will be reached before the vswitch can achieve the comparable performance level.

It's unlikely that the virtual switch will be the only application running on the System Under Test (SUT), so CPU utilization, Cache utilization, and Memory footprint should also be recorded for the virtual implementations of internetworking functions. However, internally-measured metrics such as these are not benchmarks; they may be useful for the audience (operations) to know, and may also be useful if there is a problem encountered during testing.

Benchmark Comparability between virtual and physical/hardware implementations of equivalent functions will likely place more detailed and exact requirements on the *testing systems* (in terms of stream generation, algorithms to search for max values, and their configurations of course). This is another area for standards development to appreciate. However, the is a topic for a future draft.

3.2. Continued Emphasis on Black-Box Benchmarks

External observations remain essential as the basis for Benchmarks. Internal observations with fixed specification and interpretation will be provided in parallel to assist the development of operations procedures when the technology is deployed.

3.3. New Configuration Parameters

A key consideration when conducting any sort of benchmark is trying to ensure the consistency and repeatability of test results. When benchmarking the performance of a vswitch there are many factors that can affect the consistency of results, one key factor is matching the various hardware and software details of the SUT. This section lists some of the many new parameters which this project believes are critical to report in order to achieve repeatability.

It has been the goal of the project to produce repeatable results, and a large set of the parameters believed to be critical is provided so that the benchmarking community can better appreciate the increase in configuration complexity inherent in this work. The parameter set below is assumed sufficient for the infrastructure in use by the VSPERF project to obtain repeatable results from test-to-test.

Hardware details (platform, processor, memory, and network) including:

Software details including:

Test Traffic Information:

3.4. Flow classification

Virtual switches group packets into flows by processing and matching particular packet or frame header information, or by matching packets based on the input ports. Thus a flow can be thought of a sequence of packets that have the same set of header field values, or have arrived on the same physical or logical port. Performance results can vary based on the parameters the vswitch uses to match for a flow. The recommended flow classification parameters for any vswitch performance tests are: the input port (physical or logical), the source MAC address, the destination MAC address, the source IP address, the destination IP address and the Ethernet protocol type field (although classification may take place on other fields, such as source and destination transport port numbers). It is essential to increase the flow timeout time on a vswitch before conducting any performance tests that do not intend to measure the flow setup time, see Section 3 of [RFC2889]. Normally the first packet of a particular stream will install the flow in the virtual switch 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.

3.5. Benchmarks using Baselines with Resource Isolation

This outline describes measurement of baseline with isolated resources at a high level, which is the intended approach at this time.

Figure 1 Benchmark platform forwarding capability

                                                      __
 +--------------------------------------------------+   |
 |   +------------------------------------------+   |   |
 |   |                                          |   |   |
 |   |          Simple Forwarding App           |   |  Host
 |   |                                          |   |   |
 |   +------------------------------------------+   |   |
 |   |                 NIC                      |   |   |
 +---+------------------------------------------+---+ __|
            ^                           :
            |                           |
            :                           v
 +--------------------------------------------------+
 |                                                  |
 |                traffic generator                 |
 |                                                  |
 +--------------------------------------------------+

Figure 2 Benchmark VNF forwarding capability

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

  1. Baselines:
  2. Next Steps

4. VSPERF Specification Summary

The overall specification in preparation is referred to as a Level Test Design (LTD) document, which will contain a suite of performance tests. The base performance tests in the LTD are based on the pre-existing specifications developed by BMWG to test the performance of physical switches. These specifications include:

Some of the above/newer RFCs are being applied in benchmarking for the first time, and represent a development challenge for test equipment developers. Fortunately, many members of the testing system community have engaged on the VSPERF project, including an open source test system.

In addition to this, the LTD also re-uses the terminology defined by:

It is recommended that these references are included in future benchmarking specifications:

As one might expect, the most fundamental internetworking characteristics of Throughput and Latency remain important when the switch is virtualized, and these benchmarks figure prominently in the specification.

When considering characteristics important to "telco" network functions, additional performance metrics are needed. In this case, the project specifications have referenced metrics from the IETF IP Performance Metrics (IPPM) literature. This means that the [RFC2544] test of Latency is replaced by measurement of a metric derived from IPPM's [RFC2679], where a set of statistical summaries will be provided (mean, max, min, and percentiles). Further metrics planned to be benchmarked include packet delay variation as defined by [RFC5481] , reordering, burst behaviour, DUT availability, DUT capacity and packet loss in long term testing at Throughput level, where some low-level of background loss may be present and characterized.

Tests have been designed to collect the metrics below:

Additional test specification development should include:

The flexibility of deployment of a virtual switch within a network means that it is necessary to characterize the performance of a vswitch in various deployment scenarios. The deployment scenarios under consideration include:

Figure 3 Physical port to virtual switch to physical port

                                                      __
 +--------------------------------------------------+   |
 |              +--------------------+              |   |
 |              |                    |              |   |
 |              |                    v              |   |  Host
 |   +--------------+            +--------------+   |   |
 |   |   phy port   |  vswitch   |   phy port   |   |   |
 +---+--------------+------------+--------------+---+ __|
            ^                           :
            |                           |
            :                           v
 +--------------------------------------------------+
 |                                                  |
 |                traffic generator                 |
 |                                                  |
 +--------------------------------------------------+

Figure 4 Physical port to virtual switch to VNF to virtual switch to physical port

                                                      __
 +---------------------------------------------------+   |
 |                                                   |   |
 |   +-------------------------------------------+   |   |
 |   |                 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                 |
 |                                                  |
 +--------------------------------------------------+

Figure 5 Physical port to virtual switch to VNF to virtual switch to VNF to virtual switch to physical port

                                                   __
 +----------------------+  +----------------------+  |
 |   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
 |       |       |-----------------|       v      | |
 |   +--------------+          +--------------+   | |
 |   |   phy ports  | vswitch  |   phy ports  |   | |
 +---+--------------+----------+--------------+---+_|
         ^                                 :
         |                                 |
         :                                 v
 +--------------------------------------------------+
 |                                                  |
 |                traffic generator                 |
 |                                                  |
 +--------------------------------------------------+

Figure 6 Physical port to virtual switch to VNF

                                                       __
 +---------------------------------------------------+   |
 |                                                   |   |
 |   +-------------------------------------------+   |   |
 |   |                 Application               |   |   |
 |   +-------------------------------------------+   |   |
 |       ^                                           |   |
 |       |                                           |   |  Guest
 |       :                                           |   |
 |   +---------------+                               |   |
 |   | logical port 0|                               |   |
 +---+---------------+-------------------------------+ __|
         ^
         |
         :                                            __
 +---+---------------+------------------------------+   |
 |   | logical port 0|                              |   |
 |   +---------------+                              |   |
 |       ^                                          |   |
 |       |                                          |   |  Host
 |       :                                          |   |
 |   +--------------+                               |   |
 |   |   phy port   |  vswitch                      |   |
 +---+--------------+------------ -------------- ---+ __|
            ^
            |
            :
 +--------------------------------------------------+
 |                                                  |
 |                traffic generator                 |
 |                                                  |
 +--------------------------------------------------+

Figure 7 VNF to virtual switch to physical port

                                                       __
 +---------------------------------------------------+   |
 |                                                   |   |
 |   +-------------------------------------------+   |   |
 |   |                 Application               |   |   |
 |   +-------------------------------------------+   |   |
 |                                          :        |   |
 |                                          |        |   |  Guest
 |                                          v        |   |
 |                               +---------------+   |   |
 |                               | logical port  |   |   |
 +-------------------------------+---------------+---+ __|
                                            :
                                            |
                                            v         __
 +------------------------------+---------------+---+   |
 |                              | logical port  |   |   |
 |                              +---------------+   |   |
 |                                          :       |   |
 |                                          |       |   |  Host
 |                                          v       |   |
 |                               +--------------+   |   |
 |                     vswitch   |   phy port   |   |   |
 +-------------------------------+--------------+---+ __|
                                        :
                                        |
                                        v
 +--------------------------------------------------+
 |                                                  |
 |                traffic generator                 |
 |                                                  |
 +--------------------------------------------------+

Figure 8 VNF to virtual switch to VNF

                                                   __
 +----------------------+  +----------------------+  |
 |   Guest 1            |  |   Guest 2            |  |
 |   +---------------+  |  |   +---------------+  |  |
 |   |  Application  |  |  |   |  Application  |  |  |
 |   +---------------+  |  |   +---------------+  |  |
 |              |       |  |       ^              |  |
 |              v       |  |       |              |  |  Guests
 |   +---------------+  |  |   +---------------+  |  |
 |   | logical ports |  |  |   | logical ports |  |  |
 |   |           0   |  |  |   |   0           |  |  |
 +---+---------------+--+  +---+---------------+--+__|
                 :                 ^
                 |                 |
                 v                 :               _
 +---+---------------+---------+---------------+--+ |
 |   |           1   |         |   1           |  | |
 |   | logical ports |         | logical ports |  | |
 |   +---------------+         +---------------+  | |
 |               |                 ^              | |  Host
 |               L-----------------+              | |
 |                                                | |
 |                    vswitch                     | |
 +------------------------------------------------+_|

A set of Deployment Scenario figures is available on the VSPERF Test Methodology Wiki page [TestTopo].

5. 3x3 Matrix Coverage

This section organizes the many existing test specifications into the "3x3" matrix (introduced in [I-D.ietf-bmwg-virtual-net]). Because the LTD specification ID names are quite long, this section is organized into lists for each occupied cell of the matrix (not all are occupied, also the matrix has grown to 3x4 to accommodate scale metrics when displaying the coverage of many metrics/benchmarks). The current version of the LTD specification is available [LTD].

The tests listed below assess the activation of paths in the data plane, rather than the control plane.

A complete list of tests with short summaries is available on the VSPERF "LTD Test Spec Overview" Wiki page [LTDoverV].

5.1. Speed of Activation

5.2. Accuracy of Activation section

5.3. Reliability of Activation

5.4. Scale of Activation

5.5. Speed of Operation

5.6. Accuracy of Operation

5.7. Reliability of Operation

5.8. Scalability of Operation

5.9. Summary

|------------------------------------------------------------------------|
|               |             |            |               |             |
|               |   SPEED     |  ACCURACY  |  RELIABILITY  |    SCALE    |
|               |             |            |               |             |
|------------------------------------------------------------------------|
|               |             |            |               |             |
|  Activation   |      X      |     X      |       X       |      X      |
|               |             |            |               |             |
|------------------------------------------------------------------------|
|               |             |            |               |             |
|  Operation    |      X      |      X     |       X       |      X      |
|               |             |            |               |             |
|------------------------------------------------------------------------|
|               |             |            |               |             |
| De-activation |             |            |               |             |
|               |             |            |               |             |
|------------------------------------------------------------------------|

6. Security Considerations

Benchmarking activities as described in this memo are limited to technology characterization of a Device Under Test/System Under Test (DUT/SUT) using controlled stimuli in a laboratory environment, with dedicated address space and the constraints specified in the sections above.

The benchmarking network topology will be an independent test setup and MUST NOT be connected to devices that may forward the test traffic into a production network, or misroute traffic to the test management network.

Further, benchmarking is performed on a "black-box" basis, relying solely on measurements observable external to the DUT/SUT.

Special capabilities SHOULD NOT exist in the DUT/SUT specifically for benchmarking purposes. Any implications for network security arising from the DUT/SUT SHOULD be identical in the lab and in production networks.

7. IANA Considerations

No IANA Action is requested at this time.

8. Acknowledgements

The authors appreciate and acknowledge comments from Scott Bradner, Marius Georgescu, Ramki Krishnan, Doug Montgomery, Martin Klozik, Christian Trautman, and others for their reviews.

We also acknowledge the early work in [I-D.huang-bmwg-virtual-network-performance], and useful discussion with the authors.

9. References

9.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC2285] Mandeville, R., "Benchmarking Terminology for LAN Switching Devices", RFC 2285, DOI 10.17487/RFC2285, February 1998.
[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for Network Interconnect Devices", RFC 2544, DOI 10.17487/RFC2544, March 1999.
[RFC2679] Almes, G., Kalidindi, S. and M. Zekauskas, "A One-way Delay Metric for IPPM", RFC 2679, DOI 10.17487/RFC2679, September 1999.
[RFC2889] Mandeville, R. and J. Perser, "Benchmarking Methodology for LAN Switching Devices", RFC 2889, DOI 10.17487/RFC2889, August 2000.
[RFC3918] Stopp, D. and B. Hickman, "Methodology for IP Multicast Benchmarking", RFC 3918, DOI 10.17487/RFC3918, October 2004.
[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov, S. and J. Perser, "Packet Reordering Metrics", RFC 4737, DOI 10.17487/RFC4737, November 2006.
[RFC6201] Asati, R., Pignataro, C., Calabria, F. and C. Olvera, "Device Reset Characterization", RFC 6201, DOI 10.17487/RFC6201, March 2011.
[RFC6985] Morton, A., "IMIX Genome: Specification of Variable Packet Sizes for Additional Testing", RFC 6985, DOI 10.17487/RFC6985, July 2013.

9.2. Informative References

[DanubeRel] "Danube, Fourth OPNFV Release https://wiki.opnfv.org/display/SWREL/Danube"
[I-D.huang-bmwg-virtual-network-performance] Huang, L., Rong, G., Mandeville, B. and B. Hickman, "Benchmarking Methodology for Virtualization Network Performance", Internet-Draft draft-huang-bmwg-virtual-network-performance-02, March 2017.
[I-D.ietf-bmwg-virtual-net] Morton, A., "Considerations for Benchmarking Virtual Network Functions and Their Infrastructure", Internet-Draft draft-ietf-bmwg-virtual-net-05, March 2017.
[IEEE802.1ac] https://standards.ieee.org/findstds/standard/802.1AC-2016.html, "802.1AC-2016 - IEEE Standard for Local and metropolitan area networks -- Media Access Control (MAC) Service Definition", 2016.
[IFA003] "https://docbox.etsi.org/ISG/NFV/Open/Drafts/IFA003_Acceleration_-_vSwitch_Spec/"
[LTD] Note: if the Danube Release LTD is available in artifacts at publication, we will use that URL instead., "LTD Test Specificationhttp://artifacts.opnfv.org/vswitchperf/colorado/docs/requirements/vswitchperf_ltd.html"
[LTDoverV] "LTD Test Spec Overview https://wiki.opnfv.org/display/vsperf/LTD+Test+Spec+Overview"
[OPNFV] "OPNFV Home https://www.opnfv.org/"
[RFC1242] Bradner, S., "Benchmarking Terminology for Network Interconnection Devices", RFC 1242, DOI 10.17487/RFC1242, July 1991.
[RFC5481] Morton, A. and B. Claise, "Packet Delay Variation Applicability Statement", RFC 5481, DOI 10.17487/RFC5481, March 2009.
[TestTopo] "Test Topologies https://wiki.opnfv.org/display/vsperf/Test+Methodology"
[VSPERFhome] "VSPERF Home https://wiki.opnfv.org/display/vsperf/VSperf+Home"

Authors' Addresses

Maryam Tahhan Intel EMail: maryam.tahhan@intel.com
Billy O'Mahony Intel EMail: billy.o.mahony@intel.com
Al Morton AT&T Labs 200 Laurel Avenue South Middletown,, NJ 07748 USA Phone: +1 732 420 1571 Fax: +1 732 368 1192 EMail: acmorton@att.com URI: http://home.comcast.net/~acmacm/