<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div dir="ltr"><meta http-equiv="content-type" content="text/html; charset=utf-8">I don’t think, anyone has proposed to use ‘’reserved ASNs” as a BCP, example of “ab”use of ASN0 is a de-facto artifact (unfortunate one).</div><div dir="ltr">My goal would be to provide a viable source of information to someone who is setting up a new ISP and has a very little clue as where to start. Do’s and don’t’s wrt inter-domain communities use. </div><div dir="ltr"><br></div><div dir="ltr">I really enjoyed the difference RFC7938 (<span style="color: rgb(0, 0, 0); font-family: "PT Mono", Monaco, monospace; font-size: 14px; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); -webkit-text-size-adjust: 100%; background-color: rgb(255, 253, 245);">Use of BGP for Routing in Large-Scale Data Centers</span>) made, literally 100s of companies have used it to educate themselves/ implemented their DC networking.</div><div dir="ltr"><br></div><div dir="ltr"><div dir="ltr">Cheers,<div>Jeff</div></div><div dir="ltr"><br><blockquote type="cite">On Sep 9, 2020, at 10:04, adam via NANOG <nanog@nanog.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="Generator" content="Microsoft Word 15 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--><div class="WordSection1"><p class="MsoNormal"><span style="mso-fareast-language:EN-US">I don’t agree with the use of reserved ASNs, let alone making it BCP, cause it defeats the whole purpose of the community structure.<o:p></o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US">Community is basically sending a message to an AS. If I want your specific AS to interpret the message I set it in format YOUR_ASN:<community value>, your AS in the first part of the community means that your rules of how to interpret the community value apply.<o:p></o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US">Turning AS#0 or any other reserved AS# into a “broadcast-AS#” in terms of communities (or any other attribute for that matter) just doesn’t sit right with me (what’s next? multicast-ASNs that we can subscribe to?).<o:p></o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US">All the examples in Robert’s draft or wide community RFC, all of them use an example AS# the community is addressed to (not some special reserved AS#).<o:p></o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US">Also should something like this become standard it needs to be properly standardized and implemented as a well-known community by most vendors (like RFCs defining the wide communities or addition to standard communities like no_export/no_advertise/…). This would also eliminate the adoption friction from operators rightly claiming “my AS my rules”. <o:p></o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US">adam<o:p></o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p><p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p><div style="border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt"><div><div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> NANOG <nanog-bounces+adamv0025=netconsultings.com@nanog.org> <b>On Behalf Of </b>Douglas Fischer via NANOG<br><b>Sent:</b> Tuesday, September 8, 2020 4:56 PM<br><b>To:</b> NANOG <nanog@nanog.org><br><b>Subject:</b> BGP Community - AS0 is de-facto "no-export-to" marker - Any ASN reserved to "export-only-to"?'<o:p></o:p></span></p></div></div><p class="MsoNormal"><o:p> </o:p></p><div><div><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Courier New",serif">Most of us have already used some BGP community policy to no-export some routes to some where.<br><br>On the majority of IXPs, and most of the Transit Providers, the very common community tell to route-servers and routers "Please do no-export these routes to that ASN" is:<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"> -> 0:<TargetASN><o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif">So we could say that this is a de-facto standard.<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif">But the Policy equivalent to "Please, export these routes only to that ASN" is very varied on all the IXPs or Transit Providers.<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif">With that said, now comes some questions:<br><br>1 - Beyond being a de-facto standard, there is any RFC, Public Policy, or something like that, that would define 0:<TargetASN> as "no-export-to" standard?<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif">2 - What about reserving some 16-bits ASN to use <ExpOnlyTo>:<TargetASN> as "export-only-to" standard?<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif">2.1 - Is important to be 16 bits, because with (RT) extended communities, any ASN on the planet could be the target of that policy.<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New",serif">2.2 - Would be interesting some mnemonic number like 1000 / 10000 or so.<o:p></o:p></span></p></div><div><p class="MsoNormal"><o:p> </o:p></p></div><p class="MsoNormal">-- <o:p></o:p></p><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New",serif">Douglas Fernando Fischer<br>Engº de Controle e Automação</span><o:p></o:p></p></div></div></div></div></div></blockquote></div></body></html>