Categories
Collaborations Social

thanks to visiting scholar Kensuke Fukuda (again!)

We would like to thank Kensuke Fukuda for joining us as a visiting scholar from April 2017 to February 2018.  This visit was his second to our group, and it was great having Fukuda-san back with us while he continues his work with  the National Institute of Informatics in Japan.

Kensuke’s first visit resulted in it development of DNS backscatter, a new technique that can detect scanners and spammers in IPv4.  On this visit he worked with us to understand how to adapt DNS backscatter to IPv6.  A paper about this work appears at ACM IMC 2018.

We had a going away lunch with Kensuke, his family, and part of the ANT lab in February 2018.  Because it was during the regular week, several lab members were unable to attend.

The going-away lunch for Kensuke Fukuda (on the left), with members of the ANT lab, celebrating his time here as a visiting scholar.
The going-away lunch for Kensuke Fukuda (on the left), with members of the ANT lab, celebrating his time here as a visiting scholar.
Categories
Announcements Collaborations Papers

best paper award at PAM 2017

The PAM 2017 best paper award for “Anycast Latency: How Many Sites Are Enough?”

Congratulations to Ricardo de Oliveira Schmidt (U. Twente), John Heidemann (USC/ISI), and Jan Harm Kuipers (U. Twente) for the award of  best paper at the Conference on Passive and Active Measurement (PAM) 2017 to their paper “Anycast Latency: How Many Sites Are Enough?”.

See our prior blog post for more information about the paper and its data, and the U. Twente blog post about the paper and the SIDN Labs blog post about the paper.

Categories
Announcements Collaborations Papers

best paper award at AINTEC 2016

Best paper award to Shah, Fontugne, and Papadopoulos at AINTEC 2016

Congratulations to Anant Shah, Christos Papadopoulos (Colorado State University) and Romain Fontugne (Internet Initiative Japan) for the award of  best paper at AINTEC 2016 to their paper “Towards Characterizing International Routing Detours”.

See our prior blog post for more information about the paper and its data, and the APNIC blog post about this paper.

Categories
Collaborations Social

thanks to visiting scholar Ricardo Schmidt

We would like to thank Ricardo Schmidt for joining us as a visiting scholar from October 2015 to February 2016.  Ricardo visited us from the University of Twente in the Netherlands, and brought his passion for DNS and anycast.

A paper about some technical results from his visit will appear as a technical report shortly.

We sent him off in February 2016 with an ANT group lunch.

A going-away lunch for Ricardo Schmidt (at the head of the table), celebrating his time at USC/ISI as a visiting scholar, with the ANT lab and guests.
A going-away lunch for Ricardo Schmidt (at the head of the table), celebrating his time at USC/ISI as a visiting scholar, with the ANT lab and guests.
Categories
Collaborations Social

thanks to visiting scholar Kensuke Fukuda

We would like to thank Kensuke Fukuda for joining us as a visiting scholar from September 2014 to January 2015.  It was great having Fukuda-san join us from the National Institute of Informatics in Japan and share is interest in network measurement and DNS.

Watch here for details about the technical results of his visit.  For now though, a photo of our going-away lunch with Kenuske, his family, and most of rest of the ANT lab taken in January 2015.

The going away lunch for Kensuke Fukuda (fifth from the right), celebrating his visiting as a scholar, with the ANT lab.
The going away lunch for Kensuke Fukuda (fifth from the right), celebrating his visiting as a scholar, with the ANT lab.
Categories
Announcements Collaborations Data Internet Outages

welcoming Greece to the ANT Internet Census

We’re happy to welcome Greece to our browsable Internet map at http://www.isi.edu/ant/address/browse/ !  Of course Greece has always been in our Internet censuses, but George Xylomenos and George Polyzos of the Athens University of Economics and Business (their lab) helped set up a new observation site.  Greece now provides a new vantage point for Internet censuses.

The differences in the census are small, as one would hope, since it’s a global Internet.  However, when we look at latency (the time it takes for an IP address to reply to our requests), Greece gives us a European view.

Compare the lower-left corner of the Internet, since that is European IPv4 address space:

it61g RTTs
Round-trip times from our Greek vantage point (in AUEB.gr) to the world. Observe that European IP addresses in the lower left corner are nearby (light colored).
it61w RTTs
Round-trip times from our Los Angeles-based vantage point (at isi.edu) to the world. Observe that European IP addresses in the lower left corner are distant (darker gray).

In addition to big thanks to George Xylomenos and George Polyzos of AUEB (σας ευχαριστώ!) and AUEB for institutional funding for this work.  We also thank Christos Papadopoulos (Colorado State) for helping with many details, and Colin Perkins (U. Glasgow) for discussions about potential European hosts.

Data from our Greece census is available to researchers at no cost on the same terms as our existing census data.  See our datasets page for details. Greek data starts with it61 as of 2014-08-29.

Categories
Announcements Collaborations Software releases

ANT extensions for bzip2-splitting to appear in Hadoop

The ANT project is happy to announce that our extensions to Hadoop to support splitting of bzip2-compressed files have been accepted to appear in the next Hadoop release (will be 0.21.0).

Support for compression is important in map/reduce because it reduces the amount of I/O, and because important input files (for us, our Internet address censuses) are provided in compressed format.

Splitting is important in map/reduce, because splitting allows many computers to process parts of a few big files.  Since the whole point of Hadoop and map/reduce is processing big files (for us, 4GB or more) with many computers (for us, dozens to hundreds), splitting is really essential.

Until now, Hadoop did not support splitting of compressed files.  Instead, if input data was compressed, you get at most one computer per file.  Some work-arounds were possible, but basically unpleasant, and often requiring that one rewrite all the input data is some other format.

Our extensions (see HADOOP-4012 and MAPREDUCE-830, plus HADOOP-3646 that went into 0.19.0) support Hadoop execution over bzip2 files with automatic splitting.  Getting this done was trickier than one might expect:  Hadoop really wants to decide where to split files, yet bzip2 can only support splits at specific locations that are different, and users don’t care about either of these but instead only about their record boundaries.  Fortunately, we were able to align all of these constraints, and deal with the corner cases that inevitably arise.  (What if the bzip2 marker appears in normal data?  What happens when markers exactly align, or are off-by-one?)

Abdul Qadeer did this work in 2008, working with Yuri Pradkin and me (John Heidemann), and continued to work with the patch through its getting committed.  We especially thank Chris Douglas at Yahoo for shepherding patch through the Hadoop bug tracking system, including helping clean it up and add test cases.  And we thank Doug Cutting for initially suggesting bzip2 as a splittable compression scheme.

This work was supported by NSF through the MR-Net research project (CNS-0823774).