Recommendations for using Multiple IP Addresses in Benchmarking Tests
draft-lencse-bmwg-multiple-ip-addresses-01
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Gábor Lencse , Keiichi Shima | ||
| Last updated | 2024-03-04 | ||
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draft-lencse-bmwg-multiple-ip-addresses-01
Benchmarking Methodology Working Group G. Lencse
Internet-Draft Széchenyi István University
Intended status: Informational K. Shima
Expires: 5 September 2024 SoftBank Corp.
4 March 2024
Recommendations for using Multiple IP Addresses in Benchmarking Tests
draft-lencse-bmwg-multiple-ip-addresses-01
Abstract
RFC 2544 has defined a benchmarking methodology for network
interconnect devices. Its test frame format contained fixed IP
addresses and fixed port numbers. RFC 4814 introduced pseudorandom
port numbers, but it kept the usage of a single source and
destination IP address pair when a single destination network is
used. This limitation may cause an issue when the device under test
uses Receive-Side Scaling (RSS) mechanism in the packet processing
flow. RSS has two types of implementations: the first one only
includes the IP addresses, whereas the second one also includes the
port numbers into the tuple used for hashing. Benchmarking tests
that use a single IP address pair and RFC 4814 pseudorandom port
numbers are biased against the first type of RSS implementation,
because in this case, the traffic is not distributed among the
processing elements. This document recommends the usage of
pseudorandom IP addresses in a similar manner as RFC 4814 did it with
the port numbers.
If accepted, this document updates all affected RFCs, including RFC
2544, RFC 4814, RFC 5180, RFC 8219.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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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 5 September 2024.
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Copyright Notice
Copyright (c) 2024 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 (https://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 Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Recommendation for Multiple IP Addresses . . . . . . . . . . 3
2.1. Potential Ranges for IPv4 Addresses . . . . . . . . . . . 3
2.2. Potential Ranges for IPv6 Addresses . . . . . . . . . . . 5
2.3. Considerations for the IP Address Ranges to be Used . . . 5
3. Implementation of the Recommended Solution . . . . . . . . . 6
4. Experiments and Results . . . . . . . . . . . . . . . . . . . 6
5. Considerations for Stateful Tests . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 8
A.1. 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
A.2. 01 . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
[RFC2544] has defined a comprehensive benchmarking methodology for
network interconnect devices, which is still in use. It was amended
by several RFCs which, however, did not formally update it.
[RFC4814] introduced pseudorandom port numbers (instead of fixed
ones). [RFC5180] addressed IPv6 specificities and also added
technology updates, but declared IPv6 transition technologies out of
its scope. [RFC8219] addressed the IPv6 transition technologies.
Receive-Side Scaling (RSS) aims to distribute the workload caused by
packet arrivals among the CPU cores evenly to achieve high
performance. It has two types of implementations: the first one only
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includes the IP addresses, whereas the second one also includes the
port numbers into the tuple used for hashing. [RFC4814] compliant
testers work properly in the second case, however, pseudorandom port
numbers cannot provide entropy if the Device Under Test (DUT) follows
the first type of RSS implementation, therefore, these devices
produce poor benchmarking results in [RFC4814] compliant laboratory
tests, whereas they can exhibit high performance in production
environments where the usage of multiple IP addresses ensures the
entropy for the proper operation of their RSS implementation.
Therefore, the conditions of laboratory tests should be improved to
ensure unbiased performance testing. To that end, this document
examines how the usage of multiple IP addresses can be introduced in
the performance testing of network interconnect devices using IPv4 or
IPv6 addresses observing the limitations of the ranges of special
purpose IPv4 and IPv6 addresses reserved for benchmarking
measurements. Practical recommendations are given for the usage of
pseudorandom source and destination IP addresses in the case of both
IPv4 and IPv6 following the approach of RFC 4814 regarding the port
numbers and also considering the effect of the growing number of ARP
or NDP table entries.
1.1. 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. Recommendation for Multiple IP Addresses
2.1. Potential Ranges for IPv4 Addresses
The 198.18.0.0/15 IPv4 address range was reserved for benchmarking
tests. It is divided into two halves: 198.18.0.0/16 and
198.19.0.0/16 are to be used on the two sides of the test setup.
Considering the requirement of [RFC2544] regarding the IP addresses,
the test suite SHOULD be first run with a single source and
destination address pair. Then the destination networks should be
random using the 16-23 bits of the above mentioned network addresses.
The Device Under Test (DUT) is assigned the first address of each
network (198.18.R.1/24 and 198.19.R.1/24, where R is pseudorandom in
the 0-255 interval) and the Tester can be assigned e.g., the second
address from each networks (198.18.R.2/24 and 198.19.R.2/24).
The above framework imposes serious limitations to the design of how
multiple IP addresses can be used. It means that when e.g., the very
first networks (198.18.0.0/24 and 198.19.0.0/24) are used at each
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side of the test setup, the maximum range of the IP addresses
assigned to the Tester can be 198.18.0.2/24-198.18.0.254/24 and
198.19.0.2/24-198.19.0.254/24 as shown in Figure 1. When 256
destination networks are used, then the 16-23 bits identifying the
destination networks also contribute to the entropy provided to the
hash function. When only a single destination network is used, then
the 16-23 bits can also be leveraged for generating a higher number
of IP addresses, thus their ranges can be:
198.18.0.2/16-198.18.255.254/16 and 198.19.0.2/16-198.19.255.254/16
as shown in Figure 2.
198.18.0.2/24-198.18.0.254/24 198.19.0.2/24-198.19.0.254/24
\ +----------------------------------+ /
\ | | /
+-------------| Tester |<------------+
| | | |
| +----------------------------------+ |
| |
| +----------------------------------+ |
| | | |
+------------>| DUT: IPv4 router |-------------+
198.18.0.1/24 | | 198.19.0.1/24
+----------------------------------+
Figure 1: Test setup for benchmarking IPv4 routers when using
multiple destination networks
198.18.0.2/16-198.18.255.254/16 198.19.0.2/16-198.19.255.254/16
\ +----------------------------------+ /
\ | | /
+-------------| Tester |<------------+
| | | |
| +----------------------------------+ |
| |
| +----------------------------------+ |
| | | |
+------------>| DUT: IPv4 router |-------------+
198.18.0.1/16 | | 198.19.0.1/16
+----------------------------------+
Figure 2: Test setup for benchmarking IPv4 routers when using a
single destination network
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2.2. Potential Ranges for IPv6 Addresses
The 2001:2::/48 IPv6 address range, which was reserved for
benchmarking tests, is large enough. If it is split into two halves
to be used on the two sides of the test setup as 2001:2::/49 and
2001:2:8000::/49, the ranges are abundant. Even if their first /56
subnets (2001:2::/56 and 2001:2:8000::/56) are enough to ensure 256
networks on each side of the test setup. As these networks are of
/64 size, their host ID parts are vastly abundant. For convenience
considerations, we recommend the usage of their 96-111 bits to
generate potentially 65536 different IP addresses as shown in
Figure 3 in the case when a single destination network is used. (And
the 256 destination networks can be described by the 56-63 bits as
mentioned before.)
2001:2::[0000-ffff]:2/64 2001:2:0:8000::[0000-ffff]:2/64
\ +----------------------------------+ /
\ | | /
+-------------| Tester |<------------+
| | | |
| +----------------------------------+ |
| |
| +----------------------------------+ |
| | | |
+------------>| DUT: IPv6 router |-------------+
/ | | \
/ +----------------------------------+ \
2001:2::1/64 2001:2:0:8000::1/64
Figure 3: Test setup for benchmarking IPv6 routers
2.3. Considerations for the IP Address Ranges to be Used
On the one hand, the more IP addresses are used, the more entropy is
ensured and thus the most even distribution of the load over the
processing elements can be expected. However, one the other hand,
the usage of multiple IP addresses has its costs: multiple Address
Resolution Protocol (ARP for IPv4) or Neighbor Discovery Protocol
(NDP, for IPv6) table entries are used. Increasing them over a few
thousands may have a deteriorating effect on the performance of the
DUT.
It is noted that under the typical operating conditions, a router is
not connected directly to a high number of devices. If it is a
backbone router, then it is connected directly to several other
routers. If it is a local router, then it is connected directly to a
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single upstream router (or at most a few of them) and (through a
switch) to the local hosts, the number of which is unlikely to be
higher than a few thousands. In both cases, a high number of
different IP addresses may provide entropy for hashing without
causing pressure to the ARP or NDP tables of the router.
The optimal number of different IP addresses to be used in laboratory
tests is still a research topic.
3. Implementation of the Recommended Solution
As a proof of concept, the recommended solution has been implemented
in siitperf [SIITPERF]. Multiple IPv4 and IPv6 addresses are
supported from commit number 165cb7f on September 6, 2023.
4. Experiments and Results
To demonstrate the effectiveness of the solution, OpenBSD was chosen
as the operating system of the DUT. It uses the first type of RSS
solution: only the IP addresses are used by the hash function. It
was examined how much difference the usage of multiple IP addresses
makes in the IPv4 and IPv6 throughput performance. It should be
noted that IP packet forwarding under OpenBSD was single threaded
until version 7.1. The ChangeLog of OpenBSD 7.2 [OBSD72CL] states
that "Activated parallel IP forwarding, starting 4 softnet tasks but
limiting the usage to the number of CPUs."
The test setup for the IPv4 and IPv6 measurements was according to
Figure 2 and Figure 3, respectively. However, only 1000 different IP
addresses were used at each side of the test setups to limit the
potential performance degradation caused by the high number of ARP or
NDP table entries.
The DUT was a Dell PowerEdge R730 server with two 3.2GHz Intel Xeon
E5-2667 v3 CPUs having 8 cores each, 8x16GB 2133MHz DDR4 SDRAM
(accessed quad channel), and Intel X540-T2 10GbE network adapter.
Hyper-threading was switched off in the BIOS.
All tests were executed 10 times and the median, minimum and maximum
values of the throughput results were calculated. In the case of
IPv4 packet forwarding, the usage of pseudorandom IP addresses caused
a very significant (more than 3-fold) performance increase compared
to the case when fixed IP addresses were used. In the case of IPv6,
the throughput values were significantly lower, and the increase
caused by the usage of pseudorandom IP addresses was only about 50%,
but it is still a well visible difference. All the details of the
measurements can be found in [LEN2024].
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5. Considerations for Stateful Tests
Stateful technologies like stateful NAT44 or stateful NAT64 are out
of scope of this document. They are covered by
[I-D.ietf-bmwg-benchmarking-stateful].
6. IANA Considerations
This document does not make any request to IANA.
7. Security Considerations
TBD.
8. References
8.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[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>.
[RFC4814] Newman, D. and T. Player, "Hash and Stuffing: Overlooked
Factors in Network Device Benchmarking", RFC 4814,
DOI 10.17487/RFC4814, March 2007,
<https://www.rfc-editor.org/info/rfc4814>.
[RFC5180] Popoviciu, C., Hamza, A., Van de Velde, G., and D.
Dugatkin, "IPv6 Benchmarking Methodology for Network
Interconnect Devices", RFC 5180, DOI 10.17487/RFC5180, May
2008, <https://www.rfc-editor.org/info/rfc5180>.
[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>.
[RFC8219] Georgescu, M., Pislaru, L., and G. Lencse, "Benchmarking
Methodology for IPv6 Transition Technologies", RFC 8219,
DOI 10.17487/RFC8219, August 2017,
<https://www.rfc-editor.org/info/rfc8219>.
8.2. Informative References
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[I-D.ietf-bmwg-benchmarking-stateful]
Lencse, G. and K. Shima, "Benchmarking Methodology for
Stateful NATxy Gateways using RFC 4814 Pseudorandom Port
Numbers", Work in Progress, Internet-Draft, draft-ietf-
bmwg-benchmarking-stateful-05, 23 January 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-bmwg-
benchmarking-stateful-05>.
[LEN2024] Lencse, G., "Making stateless and stateful network
performance measurements unbiased", Computer
Communications, under review, 2024,
<http://www.hit.bme.hu/~lencse/publications/ECC-2024-
multiple-ip-for-review.pdf>.
[OBSD72CL] de Raadt, T., "OpenBSD 7.2 Changelog", available online,
20 October 2022, <https://www.openbsd.org/plus72.html>.
[SIITPERF] Lencse, G., "Siitperf: An RFC 8219 compliant SIIT and
stateful NAT64/NAT44 tester written in C++ using
DPDK", source code, available from GitHub, 2019-2023,
<https://github.com/lencsegabor/siitperf>.
Appendix A. Change Log
A.1. 00
Initial version.
A.2. 01
Measurement results added.
Authors' Addresses
Gábor Lencse
Széchenyi István University
Győr
Egyetem tér 1.
H-9026
Hungary
Email: lencse@sze.hu
Keiichi Shima
SoftBank Corp.
1-7-1 Kaigan, Tokyo
105-7529
Japan
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Email: shima@wide.ad.jp
URI: https://softbank.co.jp/
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