Does Anycast Hang up on You? (extended). Wei, L. & Heidemann, J. Technical Report ISI-TR-716, USC/Information Sciences Institute, February, 2017. ![Does Anycast Hang up on You? (extended) [link]](https://bibbase.org/img/filetypes/link.svg "link")
Paper abstract bibtex Anycast-based services today are widely used commercially, with several major providers serving thousands of important websites. However, to our knowledge, there has been only limited study of how often anycast fails because routing changes interrupt connections between users and their current anycast site. While the commercial success of anycast CDNs means anycast usually works well, do some users end up shut out of anycast? In this paper we examine data from more than 9000 geographically distributed vantage points (VPs) to 11 anycast services to evaluate this question. Our contribution is the analysis of this data to provide the first quantification of this problem, and to explore where and why it occurs. We see that about 1% of VPs are \emphanycast unstable, reaching a different anycast site frequently (sometimes every query). Flips back and forth between two sites in 10 seconds are observed in selected experiments for given service and VPs. Moreover, we show that anycast instability is \emphpersistent for some VPs—a few VPs never see a stable connections to certain anycast services during a week or even longer. The vast majority of VPs only saw unstable routing towards one or two services instead of instability with all services, suggesting the cause of the instability lies somewhere in the path to the anycast sites. Finally, we point out that for highly-unstable VPs, their probability to hit a given site is constant, which means the flipping are happening at a fine granularity —per packet level, suggesting load balancing might be the cause to anycast routing flipping. Our findings confirm the common wisdom that anycast almost always works well, but provide evidence that a small number of locations in the Internet where specific anycast services are never stable.
@TechReport{Wei17a,
author = "Lan Wei and John Heidemann",
title = "Does Anycast Hang up on You? (extended)",
institution = "USC/Information Sciences Institute",
year = 2017,
sortdate = "2017-02-17",
project = "ant, retrofuturebridge, lacrend, researchroot, nipet",
jsubject = "network_security",
jlocation = "johnh: pafile",
number = "ISI-TR-716",
month = feb,
jlocation = "johnh: pafile",
keywords = "anycast, route stability, anycast instability, anycast unstable",
url = "https://ant.isi.edu/%7ejohnh/PAPERS/Wei17a.html",
pdfurl = "https://ant.isi.edu/%7ejohnh/PAPERS/Wei17a.pdf",
abstract = "
Anycast-based services today are widely used commercially, with
several major providers serving thousands of important websites.
However, to our knowledge, there has been only limited study of how
often anycast fails because routing changes interrupt connections
between users and their current anycast site. While the commercial
success of anycast CDNs means anycast usually works well, do some
users end up shut out of anycast? In this paper we examine data from
more than 9000 geographically distributed vantage points (VPs) to 11
anycast services to evaluate this question. Our contribution is the
analysis of this data to provide the first quantification of this
problem, and to explore where and why it occurs. We see that about
1\% of VPs are \emph{anycast unstable}, reaching a different anycast
site frequently (sometimes every query). Flips back and forth between
two sites in 10 seconds are observed in selected experiments for given
service and VPs. Moreover, we show that anycast instability
is \emph{persistent} for some VPs---a few VPs never see a stable
connections to certain anycast services during a week or even longer.
The vast majority of VPs only saw unstable routing towards one or two
services instead of instability with all services, suggesting the
cause of the instability lies somewhere in the path to the anycast
sites. Finally, we point out that for highly-unstable VPs, their
probability to hit a given site is constant, which means the flipping
are happening at a fine granularity ---per packet level, suggesting
load balancing might be the cause to anycast routing flipping. Our
findings confirm the common wisdom that anycast almost always works
well, but provide evidence that a small number of locations in the
Internet where specific anycast services are never stable.
"
}
Downloads: 0
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However, to our knowledge, there has been only limited study of how often anycast fails because routing changes interrupt connections between users and their current anycast site. While the commercial success of anycast CDNs means anycast usually works well, do some users end up shut out of anycast? In this paper we examine data from more than 9000 geographically distributed vantage points (VPs) to 11 anycast services to evaluate this question. Our contribution is the analysis of this data to provide the first quantification of this problem, and to explore where and why it occurs. We see that about 1% of VPs are \\emphanycast unstable, reaching a different anycast site frequently (sometimes every query). Flips back and forth between two sites in 10 seconds are observed in selected experiments for given service and VPs. Moreover, we show that anycast instability is \\emphpersistent for some VPs—a few VPs never see a stable connections to certain anycast services during a week or even longer. The vast majority of VPs only saw unstable routing towards one or two services instead of instability with all services, suggesting the cause of the instability lies somewhere in the path to the anycast sites. Finally, we point out that for highly-unstable VPs, their probability to hit a given site is constant, which means the flipping are happening at a fine granularity —per packet level, suggesting load balancing might be the cause to anycast routing flipping. Our findings confirm the common wisdom that anycast almost always works well, but provide evidence that a small number of locations in the Internet where specific anycast services are never stable. ","bibtex":"@TechReport{Wei17a,\n\tauthor = \t\"Lan Wei and John Heidemann\",\n\ttitle = \t\"Does Anycast Hang up on You? (extended)\",\n\tinstitution = \t\"USC/Information Sciences Institute\",\n\tyear = \t\t2017,\n\tsortdate = \t\t\"2017-02-17\", \n\tproject = \"ant, retrofuturebridge, lacrend, researchroot, nipet\",\n\tjsubject = \"network_security\",\n\tjlocation = \t\"johnh: pafile\",\n\tnumber = \t\"ISI-TR-716\",\n\tmonth = \tfeb,\n\tjlocation = \t\"johnh: pafile\",\n\tkeywords = \t\"anycast, route stability, anycast instability, anycast unstable\",\n\turl =\t\t\"https://ant.isi.edu/%7ejohnh/PAPERS/Wei17a.html\",\n\tpdfurl =\t\"https://ant.isi.edu/%7ejohnh/PAPERS/Wei17a.pdf\",\n\tabstract = \"\nAnycast-based services today are widely used commercially, with\nseveral major providers serving thousands of important websites.\nHowever, to our knowledge, there has been only limited study of how\noften anycast fails because routing changes interrupt connections\nbetween users and their current anycast site. While the commercial\nsuccess of anycast CDNs means anycast usually works well, do some\nusers end up shut out of anycast? In this paper we examine data from\nmore than 9000 geographically distributed vantage points (VPs) to 11\nanycast services to evaluate this question. Our contribution is the\nanalysis of this data to provide the first quantification of this\nproblem, and to explore where and why it occurs. We see that about\n1\\% of VPs are \\emph{anycast unstable}, reaching a different anycast\nsite frequently (sometimes every query). Flips back and forth between\ntwo sites in 10 seconds are observed in selected experiments for given\nservice and VPs. Moreover, we show that anycast instability\nis \\emph{persistent} for some VPs---a few VPs never see a stable\nconnections to certain anycast services during a week or even longer.\nThe vast majority of VPs only saw unstable routing towards one or two\nservices instead of instability with all services, suggesting the\ncause of the instability lies somewhere in the path to the anycast\nsites. Finally, we point out that for highly-unstable VPs, their\nprobability to hit a given site is constant, which means the flipping\nare happening at a fine granularity ---per packet level, suggesting\nload balancing might be the cause to anycast routing flipping. Our\nfindings confirm the common wisdom that anycast almost always works\nwell, but provide evidence that a small number of locations in the\nInternet where specific anycast services are never stable.\n\"\n}\n\n","author_short":["Wei, L.","Heidemann, J."],"bibbaseid":"wei-heidemann-doesanycasthanguponyouextended-2017","role":"author","urls":{"Paper":"https://ant.isi.edu/%7ejohnh/PAPERS/Wei17a.html"},"keyword":["anycast","route stability","anycast instability","anycast unstable"],"metadata":{"authorlinks":{}}},"bibtype":"techreport","biburl":"https://bibbase.org/f/dHevizJoWEhWowz8q/johnh-2023-2.bib","dataSources":["YLyu3mj3xsBeoqiHK","fLZcDgNSoSuatv6aX","fxEParwu2ZfurScPY","7nuQvtHTqKrLmgu99"],"keywords":["anycast","route stability","anycast instability","anycast unstable"],"search_terms":["anycast","hang","extended","wei","heidemann"],"title":"Does Anycast Hang up on You? (extended)","year":2017}