Tag: divoice

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congratulations to Guillermo Baltra for his PhD

I would like to congratulate Dr. Guillermo Baltra for defending his PhD at the University of Southern California in August 2023 and completing his doctoral dissertation “Improving network reliability using a formal definition of the Internet core”.

Guillermo Baltra (right) and his thesis advisor.

From the abstract:

After 50 years, the Internet is still defined as “a collection of interconnected networks”. Yet seamless, universal connectivity is challenged in several ways. Political pressure threatens fragmentation due to de-peering; architectural changes such as carrier-grade NAT, the cloud makes connectivity indirect; firewalls impede connectivity; and operational problems and commercial disputes all challenge the idea of a single set of “interconnected networks”. We propose that a new, conceptual definition of the Internet core helps disambiguate questions in analysis of network reliability and address space usage.


We prove this statement through three studies. First, we improve coverage of outage detection by dealing with sparse sections of the Internet, increasing from a nominal 67% responsive /24 blocks coverage to 96% of the responsive Internet. Second, we provide a new definition of the Internet core, and use it to resolve partial reachability ambiguities. We show that the Internet today has peninsulas of persistent, partial connectivity, and that some outages cause islands where the Internet at the site is up, but partitioned from the main Internet. Finally, we use our definition to identify ISP trends, with applications to policy and improving outage detection accuracy. We show how these studies together thoroughly prove our thesis statement. We provide a new conceptual definition of “the Internet core” in our second study about partial reachability. We use our definition in our first and second studies to disambiguate questions about network reliability and in our third study, to ISP address space usage dynamics.

Guillermo’s PhD work was supported by NSF grants CNS-1806785, CNS-2007106 and NSF-2028279 and DH S&T Cyber Security Division contract 70RSAT18CB0000014 and a DHS contract administred by AFRL as contract FA8750-18-2-0280, to USC Viterbi, the Armada de Chile, and the Agencia Nacional de Investigación y Desarrollo de Chile (ANID).

Please see his individual publications for what data is available from his research; his results are also in use in ongoing Trinocular outage detection datasets.

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Papers

new paper “Improving Coverage of Internet Outage Detection in Sparse Blocks”

We will publish a new paper “Improving Coverage of Internet Outage Detection in Sparse Blocks” by Guillermo Baltra and John Heidemann in the Passive and Active Measurement Conference (PAM 2020) in Eugene, Oregon, USA, on March 30, 2020.

From the abstract:

There is a growing interest in carefully observing the reliability of the Internet’s edge. Outage information can inform our understanding of Internet reliability and planning, and it can help guide operations. Active outage detection methods provide results for more than 3M blocks, and passive methods more than 2M, but both are challenged by sparse blocks where few addresses respond or send traffic. We propose a new Full Block Scanning (FBS) algorithm to improve coverage for active scanning by providing reliable results for sparse blocks by gathering more information before making a decision. FBS identifies sparse blocks and takes additional time before making decisions about their outages, thereby addressing previous concerns about false outages while preserving strict limits on probe rates. We show that FBS can improve coverage by correcting 1.2M blocks that would otherwise be too sparse to correctly report, and potentially adding 1.7M additional blocks. FBS can be applied retroactively to existing datasets to improve prior coverage and accuracy.

This paper defines two algorithms: Full Block Scanning (FBS), to address false outages seen in active measurements of sparse blocks, and Lone Address Block Recovery (LABR), to handle blocks with one or two responsive addresses. We show that these algorithms increase coverage, from a nominal 67% (and as low as 53% after filtering) of responsive blocks before to 5.7M blocks, 96% of responsive blocks.
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Publications Technical Report

new technical report “Improving the Optics of Active Outage Detection (extended)”

We have released a new technical report “Improving the Optics of the Active Outage Detection (extended)”, by Guillermo Baltra and John Heidemann, as ISI-TR-733.

From the abstract:

A sample block showing changes in block usage (c), and outage detection results of Trinocular (b) and improved with the Full Block Scanning Algorithm (a).

There is a growing interest in carefully observing the reliability of the Internet’s edge. Outage information can inform our understanding of Internet reliability and planning, and it can help guide operations. Outage detection algorithms using active probing from third parties have been shown to be accurate for most of the Internet, but inaccurate for blocks that are sparsely occupied. Our contributions include a definition of outages, which we use to determine how many independent observers are required to determine global outages. We propose a new Full Block Scanning (FBS) algorithm that gathers more information for sparse blocks to reduce false outage reports. We also propose ISP Availability Sensing (IAS) to detect maintenance activity using only external information. We study a year of outage data and show that FBS has a True Positive Rate of 86%, and show that IAS detects maintenance events in a large U.S. ISP.

All data from this paper will be publicly available.

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Announcements Projects

new project “Detecting, Interpreting, and Validating from Outside, In, and Control, Disruptive Events” (DIVOICE)

We are happy to announce a new project, Detecting, Interpreting, and Validating from Outside, In, and Control, Disruptive Events (DIVOICE).  

The DIVOICE project’s goal is to detect and understand Network/Internet Disruptive Events (NIDEs)—outages in the Internet.

We will work toward this goal by examining outages at multiple levels of the network: at the data plane, with tools such as Trinocular (developed at USC/ISI) and Disco (developed at IIJ); at the control plane, with tools such as BGPMon (developed at Colorado State University); and at the application layer.

We expect to improve methods of outage detection, validate the work against each other and external sources of information, and work towards attribution of outage root causes.

DIVOICE is a joint effort of the ANT Lab involving USC/ISI (PI: John Heidemann) and Colorado State University (PI: Craig Partridge).   DIVOICE builds on prior work on the LACANIC and Retro-Future Bridge and Outage projects.  DIVOICE is supported by the DHS HSARPA Cyber Security Division via contract number 70RSAT18CB0000014.

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Papers Publications

new conference paper “The Policy Potential of Measuring Internet Outages” at TPRC

We have published a new paper “The Policy Potential of Measuring Internet Outages” in TPRC46, the Research Conference on Communications, Information and Internet Policy, to be presented on September 21, 2018 at the American University, Washington College of Law.

Outages from Hurricane Irma after landfall in Florida on 2017-09-11, observed with Trinocular.

From the abstract of our paper:

Today it is possible to evaluate the reliability of the Internet. Prior approaches to measure network reliability required telecommunications providers reporting the status of their own networks, resulting in limits on the precision, timeliness, and availability of the results. Recent work in Internet measurement has shown that network outages can be observed with active measurements from a few sites, and from passive measurements of network telescopes (large, unused address space) or large network services such as content-delivery networks. We suggest that these kinds of *third-party* observations of network outages can provide data that is precise and timely. We discuss early results of Trinocular, an outage detection system using active probing developed at the University of Southern California. Trinocular has been operating continuously since November 2013, and we provide (at no charge) data covering about 4 million network blocks from around the world. This paper describes some results of Trinocular showing outages in a large U.S. Internet Service Provider, and those resulting from the 2017 Hurricane Irma in Florida. Our data shows the impact of the Broadband America policy for always-on networks, and we discuss how it might be used to address future policy questions and assist in disaster planning and recovery.

Data we describe in this paper is at https://ant.isi.edu/datasets/outage/, with visualizations at https://ant.isi.edu/outage/world/.

This paper is joint work of John Heideman, Yuri Pradkin, and Guillermo Baltra from USC/ISI, with work carried out as part of LACANIC and DIVOICE projects with DHS S&T/CSD support.