<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">I can see how BFD and lower hold & keep-alive messages help convergence time (obviously) but am wondering how useful it is in practice? Do most people peer with a directly connected interface on routers or through an intermediate switch? I would be expecting most would peer with their providers using links on the router itself and would be taking advantage of the (on by default in Cisco world) fast-external-fallover. Obviously this relies on the interface going down (so wouldn’t work with Transit over Megaport for instance or switch in between) and doesn’t help a dying control plane issue but wouldn’t the default behaviour be pretty good in helping convergence in most typical eBGP setups & failures with this feature?</div><div class=""><br class=""></div><div class="">~ Scotty O</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 27 Jan 2015, at 11:19 pm, Alex Samad - Yieldbroker <<a href="mailto:Alex.Samad@yieldbroker.com" class="">Alex.Samad@yieldbroker.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="WordSection1" style="page: WordSection1; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Hi<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">I will have to monitor that. <o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">We suffered from an outage recently, with a provider we have 2 links with. We have multiple providers.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">As a review of the incident the business asked about the 3m hold timer. In theory the way I read it, is the routes could be held for up to 3 min whilst the link is down…<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">One of the questions was why did it take soo long ~ 8-9min for traffic to appear on the other link. Waiting for feedback on that<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">I am presuming with a lower hold timer/keep alive I can get pretty fast response as its only on this providers network I am failing over.<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class="">Alex<o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125);" class=""> </span></div><div style="border-style: none none none solid; border-left-color: blue; border-left-width: 1.5pt; padding: 0cm 0cm 0cm 4pt;" class=""><div class=""><div style="border-style: solid none none; border-top-color: rgb(181, 196, 223); border-top-width: 1pt; padding: 3pt 0cm 0cm;" class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><b class=""><span lang="EN-US" style="font-size: 10pt; font-family: Tahoma, sans-serif;" class="">From:</span></b><span lang="EN-US" style="font-size: 10pt; font-family: Tahoma, sans-serif;" class=""><span class="Apple-converted-space"> </span>Tom Berryman [<a href="mailto:Tom@connectivityit.com.au" style="color: purple; text-decoration: underline;" class="">mailto:Tom@connectivityit.com.au</a>]<span class="Apple-converted-space"> </span><br class=""><b class="">Sent:</b><span class="Apple-converted-space"> </span>Tuesday, 27 January 2015 11:09 PM<br class=""><b class="">To:</b><span class="Apple-converted-space"> </span>Alex Samad - Yieldbroker<br class=""><b class="">Cc:</b><span class="Apple-converted-space"> </span>David Hughes;<span class="Apple-converted-space"> </span><a href="mailto:ausnog@lists.ausnog.net" style="color: purple; text-decoration: underline;" class="">ausnog@lists.ausnog.net</a><br class=""><b class="">Subject:</b><span class="Apple-converted-space"> </span>Re: [AusNOG] BGP hold timer values<o:p class=""></o:p></span></div></div></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">There is a bit more than just a few extra packets (as your cost) - BGP can/does have notable CPU impact on low-mid range routing gear.<o:p class=""></o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">With eBGP, you are talking propagation of your routes to the internet, so not all of the internet is going to see your changes for maybe up to 180 seconds. That said, it's likely most of it will be sooner than that.<o:p class=""></o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Tom<o:p class=""></o:p></div><div class=""><table class="MsoNormalTable" border="0" cellpadding="0"><tbody class=""><tr class=""><td colspan="2" style="padding: 0.75pt;" class=""></td></tr><tr style="orphans: auto; text-align: start; widows: auto; -webkit-text-stroke-width: 0px; word-spacing: 0px;" class=""><td style="padding: 0.75pt;" class=""></td><td style="padding: 0cm;" class=""></td></tr></tbody></table></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div class=""><blockquote style="margin-top: 5pt; margin-bottom: 5pt;" class=""><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">On 27 Jan 2015, at 11:01 pm, Alex Samad - Yieldbroker <<a href="mailto:Alex.Samad@yieldbroker.com" style="color: purple; text-decoration: underline;" class="">Alex.Samad@yieldbroker.com</a>> wrote:<o:p class=""></o:p></div></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div><div class=""><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Hi<br class=""><br class="">Okay its eBGP, currently have 4 providers, some with multiple connections. So I am thinking 6 / 20 might be good for me, business requirement for approx. 30sec response.<br class="">I am presuming all I am looking at is extra BGP packets .. every 6 sec compared to 1 min..<br class=""><br class=""><br class="">Alex<br class=""><br class=""><br class=""><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">-----Original Message-----<br class="">From: David Hughes [<a href="mailto:david@hughes.com.au" style="color: purple; text-decoration: underline;" class="">mailto:david@hughes.com.au</a>]<br class="">Sent: Tuesday, 27 January 2015 9:37 PM<br class="">To: Alex Samad - Yieldbroker<br class="">Cc:<span class="Apple-converted-space"> </span><a href="mailto:ausnog@lists.ausnog.net" style="color: purple; text-decoration: underline;" class="">ausnog@lists.ausnog.net</a><br class="">Subject: Re: [AusNOG] BGP hold timer values<br class=""><br class=""><br class="">I gave a lightning talk about this sort of thing a while ago at an APRICOT. I just<br class="">googled to find the slides and can now see just how many years ago it was.<br class="">Gotta say I'm feeling old :)<br class=""><br class="">But, it's probably still relevant although the defaults may have changed. This<br class="">reflected what we were running at the time - and we were trying to be<br class="">pretty aggressive.<br class=""><br class=""><a href="http://archive.apnic.net/meetings/21/docs/sigs/routing/routing-" style="color: purple; text-decoration: underline;" class="">http://archive.apnic.net/meetings/21/docs/sigs/routing/routing-</a><br class="">pres-hughes-bgp.pdf<br class=""><br class="">For reference I'm currently happy to run<br class=""><br class="">eBGP<span class="apple-tab-span"><o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">: 10 / 30<br class="">iBGP<span class="apple-tab-span"><o:p class=""></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">: 5 / 15<br class=""><br class="">And I'd run this even to a single upstream. If it fails at least you'll have<br class="">something in your logs to say why you fell off the net for a while. Silent<br class="">failures are a bugger to troubleshoot.<br class=""><br class=""><br class="">Thanks<br class=""><br class="">David<br class="">...<br class=""><br class=""><br class=""><br class="">On 27/01/2015, at 6:47 PM, Alex Samad - Yieldbroker<br class=""><<a href="mailto:Alex.Samad@yieldbroker.com" style="color: purple; text-decoration: underline;" class="">Alex.Samad@yieldbroker.com</a>> wrote:<br class=""><br class=""><br class=""><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">Hi<br class=""><br class="">I'm wonder what is considered "best practice" or good/responsible hold<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">timer values for BGP.<br class=""><br class=""><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><br class="">Currently I'm set at 3m, but I am considering lowering this to 30s and keep<o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class="">alive down to 20s, potentially even lower. Or if possible to use BFD & BGP,<br class="">what's the uptake on BFD ?<br class=""><br class=""><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><br class="">Alex<br class="">_______________________________________________<br class="">AusNOG mailing list<br class=""><a href="mailto:AusNOG@lists.ausnog.net" style="color: purple; text-decoration: underline;" class="">AusNOG@lists.ausnog.net</a><br class=""><a href="http://lists.ausnog.net/mailman/listinfo/ausnog" style="color: purple; text-decoration: underline;" class="">http://lists.ausnog.net/mailman/listinfo/ausnog</a><o:p class=""></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><br class="">_______________________________________________<br class="">AusNOG mailing list<br class=""><a href="mailto:AusNOG@lists.ausnog.net" style="color: purple; text-decoration: underline;" class="">AusNOG@lists.ausnog.net</a><br class=""><a href="http://lists.ausnog.net/mailman/listinfo/ausnog" style="color: purple; text-decoration: underline;" class="">http://lists.ausnog.net/mailman/listinfo/ausnog</a><o:p class=""></o:p></div></div></blockquote></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif;" class=""><o:p class=""> </o:p></div></div></div></div><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">_______________________________________________</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">AusNOG mailing list</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="mailto:AusNOG@lists.ausnog.net" style="color: purple; text-decoration: underline; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">AusNOG@lists.ausnog.net</a><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="http://lists.ausnog.net/mailman/listinfo/ausnog" style="color: purple; text-decoration: underline; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">http://lists.ausnog.net/mailman/listinfo/ausnog</a></div></blockquote></div><br class=""></div></body></html>