Weekly Routing Table Report

Mon Sep 2 13:40:35 UTC 2019

> On Sep 2, 2019, at 9:33 AM, Tony Finch <dot at dotat.at> wrote:
> 
> Patrick W. Gilmore <patrick at 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.