Tag: outage detection

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Papers Publications

new conference paper “Trinocular: Understanding Internet Reliability Through Adaptive Probing” in SIGCOMM 2013

The paper “Trinocular: Understanding Internet Reliability Through Adaptive Probing” was accepted by SIGCOMM’13 in Hong Kong, China (available at http://www.isi.edu/~johnh/PAPERS/Quan13c with cite and pdf, or direct pdf).

100% detection of outages one round or longer
100% detection of outages one round or longer (figure 3 from the paper)

From the abstract:

Natural and human factors cause Internet outages—from big events like Hurricane Sandy in 2012 and the Egyptian Internet shutdown in Jan. 2011 to small outages every day that go unpublicized. We describe Trinocular, an outage detection system that uses active probing to understand reliability of edge networks. Trinocular is principled: deriving a simple model of the Internet that captures the information pertinent to outages, and populating that model through long-term data, and learning current network state through ICMP probes. It is parsimonious, using Bayesian inference to determine how many probes are needed. On average, each Trinocular instance sends fewer than 20 probes per hour to each /24 network block under study, increasing Internet “background radiation” by less than 0.7%. Trinocular is also predictable and precise: we provide known precision in outage timing and duration. Probing in rounds of 11 minutes, we detect 100% of outages one round or longer, and estimate outage duration within one-half round. Since we require little traffic, a single machine can track 3.4M /24 IPv4 blocks, all of the Internet currently suitable for analysis. We show that our approach is significantly more accurate than the best current methods, with about one-third fewer false conclusions, and about 30% greater coverage at constant accuracy. We validate our approach using controlled experiments, use Trinocular to analyze two days of Internet outages observed from three sites, and re-analyze three years of existing data to develop trends for the Internet.

Citation: Lin Quan, John Heidemann and Yuri Pradkin. Trinocular: Understanding Internet Reliability Through Adaptive Probing. In Proceedings of the ACM SIGCOMM Conference. Hong Kong, China, ACM. August, 2013. <http://www.isi.edu/~johnh/PAPERS/Quan13c>.

Datasets (listed here) used in generating this paper are available or will be available before the conference presentation.

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Presentations

New Poster “Poster Abstract: Towards Active Measurements of Edge Network Outages” in PAM 2013

Lin Quan presented our outage work: “Poster Abstract: Towards Active Measurements of Edge Network Outages” at the PAM 2013 conference. Poster abstract is available at http://www.isi.edu/~johnh/PAPERS/Quan13a/index.html

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End-to-end reachability is a fundamental service of the Internet. We study network outages caused by natural disasters, and political upheavals. We propose a new approach to outage detection using active probing. Like prior outage detection methods, our method uses ICMP echo requests (“pings”) to detect outages, but we probe with greater density and ner granularity, showing pings can detect outages without supplemental probing. The main contribution of our work is to de ne how to interpret pings as outages: defi ning an outage as a sharp change in block responsiveness relative to recent behavior. We also provide preliminary analysis of outage rate in the Internet edge. Space constrains this poster abstract to only sketches of our approach; details and validation are in our technical report. Our data is available at no charge, see http://www.isi.edu/ant/traces/internet_outages/.

This work is based on our technical report: http://www.isi.edu/~johnh/PAPERS/Quan12a/index.html, joint work by Lin Quan, John Heidemann and Yuri Pradkin.

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Presentations

new talk “Long-term Data Collection and Analysis of Outages at the Edge” given at the AIMS workshop

John Heidemann gave the talk “Long-term Data Collection and Analysis of Outages at the Edge” at UCSD, San Diego, California on Feb. 8, 2013 as part of the CAIDA Active Internet Measurement Systems (AIMS) Workshop.  Slides are available at http://www.isi.edu/~johnh/PAPERS/Heidemann13e.html.

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This talk describes our analysis of outages in edge networks at the time of Hurricane Sandy, and how that work was enabled by long-term data collection. The analysis showed U.S. networks had double the outage rate (from 0.2% to 0.4%) on 2012-10-30, the day after Sandy landfall, and recovered after four days. We highlighted long-term data collection of Internet Surveys, a random sample of about 41,000 /24 blocks, and the characteristics that make that data suitable for re-analysis. The talk was part of the CAIDA Workshop on Active Internet Measurement Systems, hosted at UCSD.

This work is based on our recent technical report   “A Preliminary Analysis of Network Outages During Hurricane Sandy“, joint work of John Heidemann, Lin Quan, and Yuri Pradkin.

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Presentations

new abstract “Third-Party Measurement of Network Outages in Hurricane Sandy” and talk with video at FCC Workshop on Network Resiliency

We recently posted our abstract “Third-Party Measurement of Network Outages in Hurricane Sandy” at http://www.isi.edu/~johnh/PAPERS/Heidemann13c.html and the talk “Active Probing of Edge Networks: Hurricane Sandy and Beyond” at http://www.isi.edu/~johnh/PAPERS/Heidemann13d.html

These were part of the FCC Workshop on Network Resiliency at Brooklyn Law College, Brooklyn, NY on Feb. 6, 2013, chaired by Henning Schulzrinne.

Video from our talk and for the whole workshop is on YouTube.

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A summary of the talk:

This talk summarized our analysis of outages in edge networks at the time of Hurricane Sandy. This analysis showed U.S. networks had double the outage rate (from 0.2% to 0.4%) on 2012-10-30, the day after Sandy landfall, and recovered after four days. It also describes our goal of tracking all outages in the Internet. The talk was part of the FCC workshop on Network Resiliency, hosted at Brooklyn Law College by Henning Schulzrinne.

This work is based on our recent technical report   “A Preliminary Analysis of Network Outages During Hurricane Sandy“, joint work of John Heidemann, Lin Quan, and Yuri Pradkin.

 

 

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Presentations

new talk “Active Probing of Edge Networks: Outages During Hurricane Sandy” at NANOG57

John Heidemann gave the talk “Active Probing of Edge Networks: Outages During Hurricane Sandy” at NANOG57 in Orlando Florida on Feb. 5, 2013 as part of a panel on Hurricane Sandy, hosted by James Cowie at Renesys.  Slides are available at http://www.isi.edu/~johnh/PAPERS/Heidemann13b.html.

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This talk summarizes our analysis of outages in edge networks at the time of Hurricane Sandy. This analysis showed U.S. networks had double the outage rate (from 0.2% to 0.4%) on 2012-10-30, the day after Sandy landfall, and recovered after four days. The talk was part of the panel “Internet Impacts of Hurricane Sandy”, moderated by James Cowie, with presentations by John Heidemann, USC/Information Sciences Institute; Emile Aben, RIPE NCC; Patrick Gilmore, Akamai; Doug Madory, Renesys.

This work is based on our recent technical report   “A Preliminary Analysis of Network Outages During Hurricane Sandy“, joint work of John Heidemann, Lin Quan, and Yuri Pradkin.

 

 

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Publications Technical Report

new tech report “A Preliminary Analysis of Network Outages During Hurricane Sandy”

We just released a new technical report “A Preliminary Analysis of Network Outages During Hurricane Sandy”, available at ftp://ftp.isi.edu/isi-pubs/tr-685.pdf and at http://www.isi.edu/~johnh/PAPERS/Heidemann12d.pdf.

From the abstract:

This document describes our analysis of Internet outages during the October 2012 Hurricane Sandy. We assess network reliability by pinging a sample of networks and observing those that respond and then stop responding. While there are always occasional network outages, we see that the outage rate in U.S. networks doubled when the hurricane made landfall, then took about four days to recover. We confirm that this increase was due to outages in New York and New Jersey.

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Papers Publications

New Workshop paper “Visualizing Sparse Internet Events: Network Outages and Route Changes”


The paper “Visualizing Sparse Internet Events: Network Outages and Route Changes” was accepted by WIV’12 in Boston, MA (available at http://www.isi.edu/~johnh/PAPERS/Quan12b.html).

From the abstract:

To understand network behavior, researchers and enterprise network operators must interpret large amounts of network data. To understand and manage network events such as outages, route instability, and spam campaigns, they must interpret data that covers a range of networks and evolves over time. We propose a simple clustering algorithm that helps identify spatial clusters of network events based on correlations in event timing, producing 2-D visualizations. We show that these visualizations where they reveal the extent, timing, and dynamics of network outages such as January 2011 Egyptian change of government, and the March 2011 Japanese earthquake. We also show they reveal correlations in routing changes that are hidden from AS-path analysis.

Citation: Lin Quan and John Heidemann and Yuri Pradkin. Visualizing Sparse Internet Events: Network Outages and Route Changes. In Proceedings of the First ACM Workshop on Internet Visualization. Boston, MA. November, 2012. <http://www.isi.edu/~johnh/PAPERS/Quan12b.html>.

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Publications Technical Report

New Tech Report “Detecting Internet Outages with Precise Active Probing (extended)”

We just published a new technical report “Detecting Internet Outages with Precise Active Probing (extended)”, available at ftp://ftp.isi.edu/isi-pubs/tr-678b.pdf. This is an update of ISI-TR-678.

From the abstract:

Parts of the Internet are down every day, from the intentionalshutdown of the Egyptian Internet in Jan. 2011 and natural disasterssuch as the Mar. 2011 Japanese earthquake, to the thousands of smalloutages caused by localized accidents, and human error, maintenance,or choices.  Understanding these events requires efficient andaccurate detection methods, motivating our new system to detectnetwork outages by active probing.  We show that a single computer cantrack outages across the entire analyzable IPv4 Internet, probing asample of 20 addresses in all 2.5M responsive /24 address blocks.  Weshow that our approach is significantly more accurate than the bestcurrent methods, with 31% fewer false conclusions, while providing 14%greater coverage and requiring about the same probing traffic.  Wedevelop new algorithms to identify outages and cluster them to events,providing the first visualization of outages.  We carefully validateour approach, showing consistent results over two years and from threedifferent sites.  Using public BGP archives and news sources weconfirm 83% of large events.  For a random sample of 50 observedevents, we find 38% in partial control-plane information, reaffirmingprior work that small outages are often not caused by BGP.  Throughcontrolled emulation we show that our approach detects 100% offull-block outages that last at least twice our probing interval.Finally, we report on Internet stability as a whole, and the size andduration of typical outages, using core-to-edge observations with muchlarger coverage than prior mesh-based studies.  We find that about0.3% of the Internet is likely to be unreachable at any time,suggesting the Internet provides only 2.5 “nines” of availability.

Categories
Publications Technical Report

New tech report “Detecting Internet Outages with Active Probing”

We just published a new technical report “Detecting Internet Outages with Active Probing”, available at ftp://ftp.isi.edu/isi-pubs/tr-672.pdf.

From the abstract:

With businesses, governments, and individuals increasingly
dependent on the Internet, understanding its reliability is more
important than ever. Network outages vary in scope and
cause, from the intentional shutdown of the Egyptian Inter-
net in February 2011, to outages caused by the effects of
March 2011 earthquakes on undersea cables entering Japan,
to the thousands of small, daily outages caused by localized
accidents or human error. In this paper we present a new
method to detect network outages by probing entire blocks.
Using 24 datasets, each a 2-week study of 22,000 /24 address
blocks randomly sampled from the Internet, we develop new
algorithms to identify and visualize outages and to cluster
those outages into network-level events. We validate our ap-
proach by comparing our data-plane results against control-
plane observations from BGP routing and news reports, ex-
amining both major and randomly selected events. We con-
firm our results are stable from two different locations and
over more than one and half years of observations. We show
that our approach of probing all addresses in a /24 block is
significantly more accurate than prior approaches that use a
single representative for all routed blocks, cutting the num-
ber of mistake outage observations from 44% to under 1%.
We use our approach to study several large outages such as
those mentioned above. We also develop a general estimate
for how much of the Internet is regularly down, finding about
0.3% of the Internet is likely to be unreachable at any time.
By providing a baseline estimate of Internet outages, our
work lays the groundwork to evaluate ISP reliability.

Citation: Lin Quan and John Heidemann. Detecting Internet Outages with Active Probing. Technical Report N. ISI-TR-672. USC/Information Sciences Institute, May 2011. http://ftp://ftp.isi.edu/isi-pubs/tr-672.pdf