nanog mailing list archives

Re: Weekly Routing Table Report


From: Jared Mauch <jared () puck nether net>
Date: Mon, 2 Sep 2019 09:40:35 -0400



On Sep 2, 2019, at 9:33 AM, Tony Finch <dot () dotat at> wrote:

Patrick W. Gilmore <patrick () ianai net> wrote:

This time I waited for 768,000. (Everyone happy now?)

I thought the magic number for breaking old Cisco gear was 786432
(768 * 1024) ... there was a panic about it earlier this year but growth
slowed so it didn't happen as soon as they feared.

https://www.zdnet.com/article/some-internet-outages-predicted-for-the-coming-month-as-768k-day-approaches/

But looking at https://twitter.com/bgp4_table I see we passed the higher
thresold (by some metrics) last month without any apparent routing
failures so maybe the old Cisco gear isn't very important any more!

It may be that there were failures but not at the core, which is more likely.  I recall writing the internal technical 
note on the edge devices when we hit 128k and 256k numbers, especially as I was a promoter of u-RPF and this halved the 
TCAM size.  It was only certain devices/customers that may have seen an issue, AND only for new routes not older stable 
ones.  People who want to promote BGP churn as a platform solution need to keep this in mind.  It also matters if you 
have the ability to disaggregate your FIB (default) vs RIB.  I’m seeing more of this right now which I think is overall 
good.  Don’t need to install all those routes in hardware if they’re all going the same way.

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