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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Nick,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Sorry, I got that output from our border router connected to the IX, to get a better picture I should have shown it from one of our
core routers:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">sh ip bgp 182.255.99.162/19 longer-prefixes<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Lucida Console";color:#1F497D;mso-fareast-language:EN-US"> Network Next Hop Metric LocPrf Weight Path<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Lucida Console";color:#1F497D;mso-fareast-language:EN-US">* i 182.255.96.0/19 103.29.52.2 64 100 0 7575 7575 i<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Lucida Console";color:#1F497D;mso-fareast-language:EN-US">*>i 103.29.52.1 0 100 0 4826 7575 i<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Lucida Console";color:#1F497D;mso-fareast-language:EN-US">*>i 182.255.103.0/24 103.29.52.1 0 100 0 4826 7575 i<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Because the AS Path is the same length from both transit and the IX, I think it is router Id being selected and thus our transit path
(103.29.52.1) is being selected.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I did some digging around looking glasses and found that route-views.sydney.routeviews.org have a BGP session with AARnet and the AS
Path includes 24115 which is the IX route servers ASN. I am guessing this makes the situation the same at AARNet with two routes with equal AS Path length (4826 then 56284 or 24115 then 56284), and the traffic from AARNet prefers Vocus over the IX.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Ben<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></a></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> AusNOG [mailto:ausnog-bounces@lists.ausnog.net]
<b>On Behalf Of </b>Nick Pratley<br>
<b>Sent:</b> Tuesday, 28 April 2015 7:08 AM<br>
<b>To:</b> Nathan Brookfield<br>
<b>Cc:</b> ausnog@ausnog.net<br>
<b>Subject:</b> Re: [AusNOG] AARNet AS path prepending on Equinix IX<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p>Hi Ben<o:p></o:p></p>
<p>Is thiss for inbound traffic from AARNet to you?<o:p></o:p></p>
<p>I can see that the best path for outbound from your router is already via the Equinix IX.<o:p></o:p></p>
<p>To fix inbound, you could try to prepend once or twice to your transit sessions, or advertise more specific routes to peering and less specific to transit.<o:p></o:p></p>
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