<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">Carrier class core routers still cost half a million dollars each or (way) more, so it’s not uncommon for there to be 2-4 in a metro.<div><br></div><div>And there are only a few metros that have undersea cable landing stations.</div><div><br></div><div>We deploy a minimum of a pair of core routers everywhere, but with our BGP/OSPF/iBGP core your path through us generally won’t change even though there’s an alternative path with slightly lower route pref. (Absent loss of both physical path and physical alternate)<br><br><div dir="ltr"><div><span style="background-color: rgba(255, 255, 255, 0);">Ms. Lady Benjamin PD Cannon of Glencoe, ASCE<br class="">6x7 Networks & 6x7 Telecom, LLC <br class="">CEO </span></div><div><span style="background-color: rgba(255, 255, 255, 0);">lb@6by7.net<br class="">"The only fully end-to-end encrypted global telecommunications company in the world.”</span></div><div><span style="background-color: rgba(255, 255, 255, 0);"><br class="">FCC License KJ6FJJ<br class=""></span></div><span style="background-color: rgba(255, 255, 255, 0);"><br></span><div><span style="background-color: rgba(255, 255, 255, 0);">Sent from my iPhone via RFC1149.</span></div></div><div dir="ltr"><br><blockquote type="cite">On Jan 17, 2022, at 1:23 PM, Pengxiong Zhu <pzhu011@ucr.edu> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div dir="auto">Hi Paul,</div><div dir="auto"><br></div><div dir="auto">Just curious. How do you determine they are the same routers? Is it based on IP address or MAC addresses? Or using CAIDA’s router alias database?</div><div dir="auto"><br></div><div dir="auto">Also how do you draw the conclusion that the AS1299 router is indeed in Chicago? IP-geolocation based on rDNS is not always accurate though. </div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto">Pengxiong </div><div dir="auto"><br><div class="gmail_quote" dir="auto"><div dir="ltr" class="gmail_attr">On Mon, Jan 17, 2022 at 10:03 AM PAUL R BARFORD <<a href="mailto:pb@cs.wisc.edu">pb@cs.wisc.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div><span style="margin:0px;font-size:12pt;font-family:Calibri,Arial,Helvetica,sans-serif;background-color:rgb(255,255,255)"><span style="margin:0px;font-family:Calibri,Helvetica,sans-serif">Hello,</span></span></div>
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<span style="margin:0px;font-family:Calibri,Helvetica,sans-serif">I am a researcher at the University of Wisconsin. My colleagues at Northwestern University and I are studying international Internet connectivity and would appreciate your perspective on a
recent finding.</span></div>
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<span style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:black">We're using traceroute data from CAIDA's Ark project for our work. We've</span><span style="font-size:12pt;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34)"> observed
that many international links (i.e., a single hop on an end-to-end path that connects two countries where end points on the hop are identified via rDNS) tend to originate/terminate at the same routers. Said another way, we are observing a relatively small
set of routers in different countries tend to have a majority of the international connections - this is especially the case for hops that terminate in the US.
</span><span style="font-size:12pt;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34)">For
</span><span style="font-size:12pt;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34)">e</span><span style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt">xample, there is a router operated by Telia (AS1299) in Chicago that
has a high concentration of such links. We were a bit surprised by this finding since even though it makes sense that the set of providers is relatively small (i.e., those that offer global connectivity), we assumed that the set of routers that used for international
connectivity within any one country would tend to be more widely distributed (at least with respect to how they appear in traceroute data - MPLS notwithstanding).</span></div>
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<span style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt">We're interested in whether or not this is indeed standard practice and if so, the cost/benefit for</span><span style="font-size:12pt;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34)"> configuring
international connectivity in this way?</span></div>
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<span style="margin:0px;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34);background-color:rgb(255,255,255);display:inline!important">Any thoughts or insights you might have would be greatly appreciated - off-list responses are welcome.</span><br>
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<span style="margin:0px;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34);background-color:rgb(255,255,255);display:inline!important">Thank you.</span></div>
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<span style="margin:0px;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34);background-color:rgb(255,255,255);display:inline!important">Regards, PB</span></div>
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<span style="margin:0px;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34);background-color:rgb(255,255,255);display:inline!important">Paul Barford</span></div>
<span style="margin:0px;font-size:12pt;font-family:Calibri,Arial,Helvetica,sans-serif;background-color:rgb(255,255,255)"><span style="margin:0px;font-family:Calibri,Helvetica,sans-serif;color:rgb(34,34,34);background-color:rgb(255,255,255);display:inline!important">University
of Wisconsin - Madison</span></span>
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</blockquote></div></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><br>Regards,<br>Pengxiong Zhu<br>Department of Computer Science and Engineering<br>University of California, Riverside</div></div>
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