Index of /datasets/dns/root-gtld-rtt
Name Last modified Size Description
Parent Directory -
README.txt 2023-10-17 14:43 5.6K
acceptable-use-agree..> 2014-07-22 11:39 12K
config/ 2006-08-03 12:20 -
data/ 2006-06-29 09:16 -
example_code/ 2006-06-29 08:58 -
The CAIDA DNS root/gTLD RTT Dataset
Overview
--------
This dataset contains DNS roundtrip time (RTT) information useful for
studying conditions within the global Internet, and the way it has
changed over the last few years. DNS RTTs are influenced by
several factors, including remote server loading, congestion within
Internet routes, route changes, and local effects such as link or
equipment failures.
Domain nameservers such as BIND use various algorithms to select which of the
13 root or gTLD servers they will ask to resolve a top-level domain name. By
watching requests to root/gTLD at the boundary of a campus (i.e. large
enterprise) network, and the responses to them, one can make passive
measurements of the RTT to all of the root/gTLD servers which the site has
routes to.
This data was collected using NeTraMet,
https://www.caida.org/catalog/software/netramet/index
producing daily data files in NeTraMet's 'flow data file' format,
from several different sites. The data available covers the
following periods:
UC San Diego (UCSD) from 8 Jan 2002 to 9 Aug 2003
U Colorado (CU) from 8 Jan 2003 to 4 Apr 2008
WIDE (U Tokyo) from 1 Jun 2004 to 27 Sep 2009
WIDE (U Fujisawa) from 13 Jul 2005 to 15 Jun 2009
U Auckland (UA) from 11 Nov 2002 to 5 Jan 2012
and from 19 Mar 2014 to present
It was collected at five-minute intervals using an SRL (RFC 2723)
ruleset called 'dns-root.srl' (available with the data).
A web page allowing you to examine 5-minute median RTT values over
periods of 1 to 7 days appears at:
https://www.caida.org/cgi-bin/dns_perf/main.pl
The NeTraMet flow data file layout is described in
www2.auckland.ac.nz/net/Accounting/ntmref.pdf
Flow data files contain 2 types of lines:
- control record lines, these start with a '#' (pound-sign).
- flow data records
Each file begins with a header giving details of when the
file was created, and the format of its data records. The
format is described by a '#Format' record, listing the RTFM attributes
requested in the dns-root ruleset.
In this dataset, the NeTraMet meters were read every five minutes; flow data
for each five-minute interval appears between '#Time' and '#Enddata'
records in the files.
The data was collected using NeTraMet's ToTurnaround attribute,
i.e. each flow record contains an RTT distribution for one
root or gTLD, as described in
https://www.caida.org/outreach/papers/2002/nsrtd/
If there are less than 100 (later 120) data points, their
actual values are saved in the flow data record. Otherwise the
data is binned, using bounds generated from the data. This
approach preserves the maximum accuracy for the RTT values.
NeTraMet versions 51b4 (21 Sep 04) through 51b6 (15 Mar 05)
had a bug in its handling of 'dynamic' distributions.
If such a distribution had 120 or less data values, the distribution
is written in the flow data file as a type 5 distribution, i.e.
a list of actual values. These are correct.
However, if there were more than 120 values, NeTraMet computes
lower and upper limits, and uses them to produce a 'binned'
distribution, type 6. The values are bin counts, those counts
are correct. Unfortunately, the bug corrupted the computed
upper limit, producing distributions which always had an upper
limit of 7000 (700 ms). To produce actual values for the bin
upper edges, one needs correct limit values - these are incorrect,
and should NOT be used. The (corrupted) type 6 distributions
remain in the .dif files, they have not been removed.
The affected date ranges are:
UC San Diego not affected
Auckland and Colorado: Mon 15 Sep 04 through Wed 16 Mar 05
Tokyo and Fujisawa: Mon 15 Sep 04 through Wed 9 Nov 05
The Auckland and Colorado data doesn't have very many type 6
distributions, so this isn't too much of a problem.
For the WIDE data (Tokyo and Fujisawa), the root distributions seem
mostly unaffected, but the gTLD distributions have very high counts
per 5-minute reading interval, so there is almost no usable gTLD RTT
data from the WIDE NeTraMet meter while the buggy version(s) were running.
A sample perl program, dnsroot_to_dat.pl, is provided to demonstrate
one approach to extracting RTT distributions from the flow data files.
Acceptable Use Agreement
------------------------------
https://www.caida.org/about/legal/aua/public_aua/
Attribution
-----------
When referencing this dataset (as required by the AUA), please use:
The CAIDA DNS root/gTLD RTT Dataset,
https://www.caida.org/catalog/datasets/dns_root_gtld_rtt_dataset
Users are encouraged to include the following attribution in the
acknowledgments section of their document:
Support for the DNS root/gTLD RTT Dataset is provided by
CAIDA, WIDE, the University of Colorado and the University of Auckland.
Sponsors
--------
Thanks to:
* The University of Auckland, for their support in developing
early versions of NeTraMet and the standards effort leading up
to the RTFM system.
* CAIDA for their ongoing support of NeTraMet development, making
it a more versatile research tool.
* The WAND group at Waikato University for support in making NeTraMet work
with early versions DAG cards.
* Endace Technologies for support with newer versions of DAG cards.
Special thanks (mostly for their help in setting up and maintaining
the NeTraMet meters) to :
* U Auckland (Russell Fulton)
* CAIDA (Duane Wessels, Dan Andersen)
* U Colorado (Robert Roybal)
* WIDE (Yuji Sekiya, Kenjiro Cho)
More Information
----------------
For more information on NeTraMet, see:
https://www.caida.org/catalog/software/netramet/