Network Working Group I. Learmonth
Internet-Draft Tor Project
Intended status: Informational December 12, 2018
Expires: June 15, 2019
Guidelines for Performing Safe Measurement on the Internet
draft-learmonth-pearg-safe-internet-measurement-01
Abstract
Researchers from industry and academia will often use Internet
measurements as a part of their work. While these measurements can
give insight into the functioning and usage of the Internet, they can
come at the cost of user privacy. This document describes guidelines
for ensuring that such measurements can be carried out safely.
Note
Comments are solicited and should be addressed to the research
group's mailing list at pearg@irtf.org and/or the author(s).
The sources for this draft are at:
https://github.com/irl/draft-safe-internet-measurement
Status of This Memo
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This Internet-Draft will expire on June 15, 2019.
Copyright Notice
Copyright (c) 2018 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/license-info) in effect on the date of
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1. Introduction
When performing research using the Internet, as opposed to an
isolated testbed or simulation platform, means that you research co-
exists in a space with other users. This document outlines
guidelines for academic and industry researchers that might use the
Internet as part of scientific experiementation.
Following the guidelines contained within this document is not a
substitute for any institutional ethics review process you may have,
although these guidelines could help to inform that process.
Similarly, these guidelines are not legal advice and local laws
should be considered before starting any experiment that could have
adverse impacts on user privacy.
Considerations are grouped into two categories: those that primarily
apply to active measurements and those that primarily apply to
passive measurements. Some of these considerations may be applicable
to both depending on the experiment design.
2. Active measurements
Active measurements generate traffic. Performance measurements such
as TCP throughput testing [RFC6349] or functional measurements such
as the feature-dependent connectivity failure tests performed by
[PATHspider] both fall into this category.
2.1. Use a testbed
Wherever possible, use a testbed. An isolated network means that
there are no other users sharing the infrastructure you are using for
your experiments.
When measuring performance, competing traffic can have negative
effects on the performance of your test traffic and so the testbed
approach can also produce more accurate and repeatable results than
experiments using the public Internet.
WAN link conditions can be emulated through artificial delays and/or
packet loss using a tool like [netem]. Competing traffic can also be
emulated using traffic generators.
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2.2. Only record your own traffic
When performing measurements be sure to only capture traffic that you
have generated. Traffic may be identified by IP ranges or by some
token that is unlikely to be used by other users.
Again, this can help to improve the accuracy and repeatability of
your experiment. [RFC2544], for performance benchmarking, requires
that any frames received that were not part of the test traffic are
discarded and not counted in the results.
2.3. Be respectful of other's infrastructure
If your experiment is designed to trigger a response from
infrastructure that is not your own, consider what the negative
consequences of that may be. At the very least your experiment will
consume bandwidth that may have to be paid for.
In more extreme circumstances, you could cause traffic to be
generated that causes legal trouble for the owner of that
infrastructure. The Internet is a global network crossing many legal
jurisdictions and so what may be legal for you is not necessarily
legal for everyone.
If you are sending a lot of traffic quickly, or otherwise generally
deviate from typical client behaviour, a network may identify this as
an attack which means that you will not be collecting results that
are representative of what a typical client would see.
3. Passive measurements
Performing passive measurements requires existing traffic. Passive
measurements can help to inform new developments in Internet
protocols but can also carry risk.
3.1. Consider the expectation of privacy
If you are in a position to perform passive measurements of live
network traffic, you are also in a position of responsibility. Users
of a network will have certain expectations of privacy and those
expectations may not align with the privacy guarantees offered by the
technologies they are using. As a thought experiment, consider how
users might respond if you asked for their informed consent for the
measurements you'd like to perform.
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3.2. Only collect data that is safe to make public
When deciding on the data to collect, assume that any data collected
might become public. There are many ways that this could happen,
through operation security mistakes or compulsion by a judicial
system.
3.3. Minimization
For all data collected, consider whether or not it is really needed.
3.4. Aggregation
When collecting data, consider if the granularity can be limited by
using bins or adding noise. XXX: Differential privacy.
3.5. Source Aggregation
Do this at the source, definitely do it before you write to disk.
[Tor.2017-04-001] presents a case-study on the in-memory statistics
in the software used by the Tor network, as an example.
4. Risk Analysis
The benefits should outweigh the risks. Consider auxiliary data
(e.g. third-party data sets) when assessing the risks.
5. Security Considerations
Take reasonable security precautions, e.g. about who has access to
your data sets or experimental systems.
6. IANA Considerations
This document has no actions for IANA.
7. Acknowledgements
Many of these considerations are based on those from the
[TorSafetyBoard] adapted and generalised to be applied to Internet
research.
8. Informative References
[netem] Stephen, H., "Network emulation with NetEm", April 2005.
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[PATHspider]
Learmonth, I., Trammell, B., Kuehlewind, M., and G.
Fairhurst, "PATHspider: A tool for active measurement of
path transparency", DOI 10.1145/2959424.2959441, July
2016,
<https://dl.acm.org/citation.cfm?doid=2959424.2959441>.
[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>.
[RFC6349] Constantine, B., Forget, G., Geib, R., and R. Schrage,
"Framework for TCP Throughput Testing", RFC 6349,
DOI 10.17487/RFC6349, August 2011,
<https://www.rfc-editor.org/info/rfc6349>.
[Tor.2017-04-001]
Herm, K., "Privacy analysis of Tor's in-memory
statistics", Tor Tech Report 2017-04-001,
<https://research.torproject.org/techreports/
privacy-in-memory-2017-04-28.pdf>.
[TorSafetyBoard]
Tor Project, "Tor Research Safety Board",
<https://research.torproject.org/safetyboard.html>.
Author's Address
Iain R. Learmonth
Tor Project
Email: irl@torproject.org
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