Characterization and Benchmarking Methodology for Power in Networking Devices
draft-cprjgf-bmwg-powerbench-04
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Carlos Pignataro , Romain Jacob , Giuseppe Fioccola , Qin Wu | ||
| Last updated | 2025-01-30 | ||
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draft-cprjgf-bmwg-powerbench-04
Benchmarking Methodology Working Group C. Pignataro
Internet-Draft NC State University
Intended status: Standards Track R. Jacob
Expires: 3 August 2025 ETH Zürich
G. Fioccola
Q. Wu
Huawei
30 January 2025
Characterization and Benchmarking Methodology for Power in Networking
Devices
draft-cprjgf-bmwg-powerbench-04
Abstract
This document defines a standard mechanism to measure, report, and
compare power usage of different networking devices and under
different network configurations and conditions.
Status of This Memo
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Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Aim and Scope . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Replicability and Comparability . . . . . . . . . . . . . 3
1.3. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Total Weighted Capacity of the interfaces . . . . . . . . 4
2.2. Total Weighted Power . . . . . . . . . . . . . . . . . . 5
2.3. Energy Efficiency Ratio . . . . . . . . . . . . . . . . . 6
2.4. Total Power . . . . . . . . . . . . . . . . . . . . . . . 7
3. Energy Consumption Benchmarking . . . . . . . . . . . . . . . 8
4. Test Methodology . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Test Setup . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Traffic and Device Characterization . . . . . . . . . . . 9
5. Reporting Format . . . . . . . . . . . . . . . . . . . . . . 10
6. Benchmarking Tests . . . . . . . . . . . . . . . . . . . . . 10
6.1. Throughput . . . . . . . . . . . . . . . . . . . . . . . 10
6.2. Base Power . . . . . . . . . . . . . . . . . . . . . . . 11
6.3. Idle Power . . . . . . . . . . . . . . . . . . . . . . . 11
6.4. Idle+ Power . . . . . . . . . . . . . . . . . . . . . . . 12
6.5. Energy Consumption with Traffic Load . . . . . . . . . . 12
6.6. Energy Efficiency Ratio . . . . . . . . . . . . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . 13
10.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
Energy efficiency is becoming increasingly important in the operation
of network infrastructure. Network devices are typically always on,
but in some cases, they run at very low average utilization rates.
Both network utilization and energy consumption of these devices can
be improved, and that starts with a normalized characterization
[RFC7460]. The benchmarking methodology defined here will help
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operators to get a more accurate idea of the power drawn by their
network and will also help vendors to test the energy efficiency of
their devices [RFC6988].
There is no standard mechanism to benchmark the power utilization of
networking devices like routers or switches.
[I-D.manral-bmwg-power-usage] started to analyze the issue. This
document defines the mechanism to correctly characterize and
benchmark the energy consumption of networking devices to better
estimate and compare their power usage.
1.1. Aim and Scope
Benchmarking can be understood to serve two related but different
objectives:
Assessing "which system performs best" over a set of well-defined
scenarios.
Measuring the contribution of sub-systems to the overall system's
performance (also known as "micro-benchmark").
Achieving either objectives requires a well-defined set of principles
prescribing what must be measured, how, and how to report the
results. Providing those principles is the objective of this draft.
These are simply called "the benchmark" in the rest of this draft.
The benchmark aims to compare the energy efficiency for individual
devices (routers and switches belonging to similar device classes).
In addition, it aims to showcase the effectiveness of various energy
optimization techniques for a given device and load type, with the
objective of fostering improvements in the energy efficiency of
future generations of devices.
1.2. Replicability and Comparability
Replicability is defined as achieving the same results with newly
collected data. Formally, it is a pre-requisite for benchmarking.
Benchmark results are meant to be compared, and this comparison is
not sound is the individual results are not replicable.
As discussed later in this draft, replicability in power measurements
is complex as power is affected by a wide range of parameters, some
of which are hard to control e.g., the room temperature.
Striving for "perfect" replicability would lead to prescribe
extremely precisely all the power-impacting factors in the test
setup. We argue that this is unrealistic and counter-productive. An
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overly prescriptive benchmark becomes more complicated to perform.
Furthermore, results would then be comparable only across benchmark
results obtained under the exact same test conditions, which becomes
increasingly less likely as we prescribe more and more.
Instead, the benchmark described in this draft proposes to report on
a number of power-impacting factors, but does not enforce specific
values or settings for those. The aim is to make the benchmark
easier to perform. The comparison between benchmark results may be
somewhat less accurate or fair than with a more prescriptive
benchmark, but the hope is to have many more comparison points
available, which would ultimately provide a more robust image of the
devices power demands and their evolution over time.
In short: this draft argues it is better to have many benchmark
results with a higher uncertainty than a few very precise but hardly
comparable ones.
1.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Terminology
2.1. Total Weighted Capacity of the interfaces
The total weighted capacity of the interfaces (T) is the weighted sum
of all interface throughputs.
Definition:
T = B1*T1 +...+ Bi*Ti +...+ Bm*Tm
Discussion:
Ti is the total capacity of the interfaces for a fixed
configuration model and traffic load (the sum of the interface
bandwidths)
Bi is the weighted multiplier for different traffic levels (note
that B1+...+Bj+...+Bm = 1, weight multipliers may be specified for
router, switch differently, 3 typical weighted multipliers are
0.1,0.8,0.1)
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m is the number of traffic load levels (if it is considered 100%,
30%, 0%; m = 3) Note that traffic load levels may be specified
differently for router and switch, e.g., traffic level 100%,10%,0%
for access router, traffic level 100%,30%,0% for core router and
data center switch.
Measurement units:
Gbps.
Issues
The traffic loads and the weighted multipliers need to be clearly
established a priori.
It is unclear if the definition of the Ti's is/should be linked to
the traffic load levels. For a given port configuration (which
may result in 50% of the total capacity a device can provide), one
may be interested in traffic load of e.g., 5% or 10% or the total
capacity (not only 50%).
See Also:
[ETSI-ES-203-136],[ITUT-L.1310] ,[ATIS-0600015.03.2013].
2.2. Total Weighted Power
The total weighted power (P) is the weighted sum of all power
calculated for different traffic loads.
Definition:
P = B1*P1 +...+ Bi*Pi +...+ Bm*Pm
Discussion:
Pi is the Power of the equipment in each traffic load level (e.g.
100%, 30%, 0%)
Bi is the weighted multiplier for different traffic levels (note
that B1+...+Bj+...+Bm = 1)
m is the number of traffic load levels (if it is considered 100%,
30%, 0%; m = 3)
Measurement units:
Watt.
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Issues:
The traffic loads and the weighted multipliers need to be clearly
established a priori.
Importantly, the traffic must be forwarded of the correct port!
It would be easy to cut power down by dropping all traffic, and,
naturally, we do not want that. A tolerance on packet loss and/or
forwarding error must be specified somehow. That tolerance could
be zero for some benchmark problems (e.g., Non packet loss (NDR)
estimation), and non-zero for others. Tolerating some errors may
be interesting to navigate the design space of energy saving
techniques, such as approximate computing/routing. According to
measurement procedure in section 6.5 of [ATIS-0600015.03.2013],
the Equipment Unit Test (EUT) should be able to return to full NDR
load. Failure to do so disqualifies the test results.
See Also:
[ETSI-ES-203-136],[ITUT-L.1310] ,[ATIS-0600015.03.2013].
2.3. Energy Efficiency Ratio
Energy Efficiency Ratio (EER) is defined as the throughput forwarded
by 1 watt and it is introduced in [ETSI-ES-203-136]. A higher EER
corresponds to a better the energy efficiency.
Definition:
EER = T/P
Discussion:
T is the total weighted sum of all interface throughputs
P is the weighted power for different traffic loads
Measurement units:
Gbps/Watt.
Issues:
The traffic loads and the weighted multipliers need to be clearly
established a priori.
See Also:
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[ETSI-ES-203-136],[ITUT-L.1310] ,[ATIS-0600015.03.2013].
2.4. Total Power
The total power (Ptot) is the power of the entire equipment, measured
as the sum the power drawn by all of the equipment's power supply
units.
Definition:
Ptot = Pu1 +...+ Pui +...+ Pun
Discussion:
Pui is the power that is drawn by one power supply unit of the
equipment
n is the number of power supply units
Measurement units:
Watt.
Issues:
The total power depends on many different factors, including the
running configuration, the number and type of transceiver
connected, the forward traffic volume and pattern, the version of
the operating system, the room temperature and humidity/other
environmental dimensions, the aging of parts, etc. This metric
does not allow to compare two equipments against each over, but it
may be enough to assess the effect of a change on the same
equipment; e.g., for optimizing the power draw by changing the
running configuration.
Importantly, the traffic must be forwarded of the correct port!
It would be easy to cut power down by dropping all traffic, and we
of course do not want that. A tolerance on packet loss and/or
forwarding error must be specified somehow. That tolerance could
be zero for some benchmark problems, and non-zero for others.
Tolerating some errors may be interesting to navigate the design
space of energy saving techniques, such as approximate computing/
routing.
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3. Energy Consumption Benchmarking
The maximum power drawn by a device does not accurately reflect the
power under a normal workload. Indeed, the energy consumption of a
networking device depends on its configuration, connected
transceivers, and traffic load. Relying merely on the maximum rated
power can overestimate the total energy of the networking devices.
A network device consists of many components, each of which draws
power (for example, it is possible to mention the power draw of the
CPU, data forwarding ASIC, memory, fan, etc.). Therefore, it is
important to formulate a consistent benchmarking method for network
devices and consider the workload variation and test conditions.
Enforcing controlled conditions on test conditions (e.g.,
Temperature) is important for test procedure to make sure test
conditions repeatable [RFC6985]. The measurement condition reported
in [ATIS-0600015.2009] and [ITUT-L.1310] should be applied, e.g., the
power measurements shall be performed in a laboratory environment
under specific range of temperature, humidity and atmosphere
pressure.
4. Test Methodology
4.1. Test Setup
The test setup in general is compliant with [RFC2544]. The Device
Under Test (DUT) is connected to a Tester and a Power Meter. The
Power Meter allows to measure the energy consumption of the device
and can be used to measure power under various configurations and
conditions. Tests MUST be done by running one or several of the
predefined traffic traces, which are crafted to test different power
hungry tasks related to packet processing. The Tester is also a
traffic generator that enables changing traffic conditions. It is
OPTIONAL to choose a non-equal proportion for upstream and downstream
traffic.
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+----------+
+-------| Tester |<-------+
| +-----| |<-----+ |
| | +----------+ | |
| | | |
| | +--------+ | |
| +----->| |-------+ |
+------->| DUT |---------+
| |
+--------+
|
|
+----------+
| Power |
| Meter |
+----------+
Figure 1: Test Setup
It is worth mentioning that the DUT also dissipates significant heat.
That means that part of the power is used for actual work while the
rest is dissipated as heat. This heating can lead to more power
drawn by fans/ compressor for cooling the devices. The benchmarking
methodology does not measure the power drawn by external cooling
infrastructure. The Power Meter only measures the internal energy
consumption of the device.
4.2. Traffic and Device Characterization
The traffic load supported by a device affects its energy
consumption. Therefore, the benchmark MUST include different traffic
loads.
The traffic load must specify packet sizes, packet rates, and inter-
packet delays, as all may affect the energy consumption of network
devices. To enable replicable and comparable results, the benchmark
specifies a set of traffic traces that MUST be used. Those traces
are described below and made available "ready to use".
There are different interface types on a network device and the power
usage also depends on the kind of connector/transceiver used. The
interface type used needs to be specified as well.
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5. Reporting Format
The benchmark focuses on data that is either controllable (e.g., the
number of active ports) or that can be externally measured (e.g., the
total power). Factors that are not measurable externally (e.g., CPU
load, PSU efficiency) are intentionally left out.
Network Device Hardware and Software versions:
For the benchmarking tests, it must be specified.
Number and type of line cards:
For each test the total number of line cards and their types can
be varied and must be specified.
Number of enabled ports:
For each test the number of enabled and disabled ports must be
specified.
Number of active ports:
For each test the number of active and inactive ports must be
specified.
Port settings and interface types:
For each test the port configuration and settings need to be
specified.
Port Utilization:
For each test the port utilization of each port must be specified.
The actual traffic load can use the information defined in
[RFC2544].
Traffic trace:
For each test, the traffic trace used (amongst those prescribed by
the benchmark) must be specified.
Power measurement:
For each test it must be specified. All power measurements are
done in Watts.
6. Benchmarking Tests
6.1. Throughput
Objective:
To determine the DUT throughput according to [RFC2544].
Procedure:
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The test is done using a multi-port setup as specified in
Section 16 and Section 26.1 of [RFC2544].
Reporting format:
The results of the throughput SHOULD be reported according to
Section 5.
6.2. Base Power
Objective:
To determine the base power drawn by the network device in its
factory settings.
Procedure:
The measurement is done with the device in its factory settings,
after it finished booting, and without any transceiver plugged in.
Reporting format:
The results of the power measurement SHOULD be reported according
to Section 5.
Note:
This measurement is useful to assess the energy efficiency of
default settings.
6.3. Idle Power
Objective:
To determine the power drawn by the network device in normal
operation but without forwarding traffic.
Procedure:
The measurement is done with the device fully configured to
forward traffic but without any traffic actually present. All
interfaces MUST be up.
Reporting format:
The results of the power measurement SHOULD be reported according
to Section 5.
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Note:
This measurement is useful to assess the energy used to activate
the internal components used by the device to forward traffic. It
also captures the efficiency of the device at activating some
"low-power mode" when there is no traffic to forward.
6.4. Idle+ Power
Objective:
To determine the power drawn by the network device in normal
operation with very small but non-zero traffic to forward.
Procedure:
The measurement is done with the device fully configured and the
"minimum" traffic trace
Reporting format:
The results of the power measurement SHOULD be reported according
to Section 5.
Note:
The "minimum" traffic trace creates a bidirectional flow of 1 pps
on all active interfaces. By comparison with the "Idle Power"
measurement, this measurement captures the power cost of taking
the device out of its "low-power mode."
6.5. Energy Consumption with Traffic Load
Objective:
To determine the power drawn by a device. The dynamic power,
which is added to the idle+ power, should be proportional to its
traffic load.
Procedure:
A specific number of packets at a specific rate is sent to
specific ports/linecards of the DUT. All DUT ports must operate
under a specific traffic load, which is a percentage of the
maximum throughput.
Reporting format:
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The results of the power measurement SHOULD be reported according
to Section 5.
6.6. Energy Efficiency Ratio
Objective:
To determine the energy efficiency of the DUT.
Procedure:
Collect the data for all the traffic loads and apply the formula
of Section 2. For example, with all DUT ports operating stably
under a percentage of the maximum throughput (e.g. 100%, 30%, 0%),
record the average input power and calculate the total weighted
power P and then the EER .
Reporting format:
The results of the energy efficiency ratio SHOULD be reported
according to Section 5.
7. Security Considerations
The benchmarking characterization described in this document is
constrained to a controlled environment (as a laboratory) and
includes controlled stimuli. The network under benchmarking MUST NOT
be connected to production networks.
Beyond these, there are no specific security considerations within
the scope of this document.
8. IANA Considerations
This document has no IANA actions.
9. Acknowledgements
We wish to thank the authors of [I-D.manral-bmwg-power-usage] for
their analysis and start on this topic.
10. References
10.1. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC7460] Chandramouli, M., Claise, B., Schoening, B., Quittek, J.,
and T. Dietz, "Monitoring and Control MIB for Power and
Energy", RFC 7460, DOI 10.17487/RFC7460, March 2015,
<https://www.rfc-editor.org/info/rfc7460>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
10.2. Informative References
[ATIS-0600015.03.2013]
ATIS, "ATIS-0600015.03.2013: Energy Efficiency for
Telecommunication Equipment: Methodology for Measurement
and Reporting for Router and Ethernet Switch Products",
2013.
[ETSI-ES-203-136]
ETSI, "ETSI ES 203 136: Environmental Engineering (EE);
Measurement methods for energy efficiency of router and
switch equipment", 2017, <https://www.etsi.org/deliver/
etsi_es/203100_203199/203136/01.02.00_50/
es_203136v010200m.pdf>.
[I-D.manral-bmwg-power-usage]
Manral, V., Sharma, P., Banerjee, S., and Y. Ping,
"Benchmarking Power usage of networking devices", Work in
Progress, Internet-Draft, draft-manral-bmwg-power-usage-
04, 12 March 2013, <https://datatracker.ietf.org/doc/html/
draft-manral-bmwg-power-usage-04>.
[ITUT-L.1310]
ITU-T, "L.1310 : Energy efficiency metrics and measurement
methods for telecommunication equipment", 2020,
<https://www.itu.int/rec/T-REC-L.1310/en>.
[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544,
DOI 10.17487/RFC2544, March 1999,
<https://www.rfc-editor.org/info/rfc2544>.
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[RFC6985] Morton, A., "IMIX Genome: Specification of Variable Packet
Sizes for Additional Testing", RFC 6985,
DOI 10.17487/RFC6985, July 2013,
<https://www.rfc-editor.org/info/rfc6985>.
[RFC6988] Quittek, J., Ed., Chandramouli, M., Winter, R., Dietz, T.,
and B. Claise, "Requirements for Energy Management",
RFC 6988, DOI 10.17487/RFC6988, September 2013,
<https://www.rfc-editor.org/info/rfc6988>.
Authors' Addresses
Carlos Pignataro
North Carolina State University
United States of America
Email: cpignata@gmail.com, cmpignat@ncsu.edu
Romain Jacob
ETH Zürich
Switzerland
Email: jacobr@ethz.ch
Giuseppe Fioccola
Huawei
Italy
Email: giuseppe.fioccola@huawei.com
Qin Wu
Huawei
China
Email: bill.wu@huawei.com
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