We just changed upstreams on Friday and the bgp.tools website still showed us 
as having both upstreams. Turns out some Russian site (AS69xxx or something) 
held on to the route for 3 days before it vanished. The next upstream they 
showed was 1299 (Arelion), so it does happen.

-----Original Message-----
From: Ben Cartwright-Cox via NANOG <[email protected]> 
Sent: Tuesday, March 3, 2026 12:43
To: [email protected]
Cc: Ben Cartwright-Cox <[email protected]>
Subject: Re: Can route-views be trusted?

(bgp.tools owner hat on)

It's entirely possible that things do actually get stuck in routing tables, and 
there [are/have been] some persistent bugs in especially Extreme OS around this 
particular failure mode for several years, there are also some similar bugs in 
certain configurations of JunOS that can easily cause this, FRR configured with 
weird flap dampening parameters can also do this...

Depending on the mission of the route collector collecting these stuck routes 
is either a feature ( it is interesting to study the propagation of these 
"stuck" routes ) or a bug ( it is annoying for customers to potentially see 
routes that are not really there )

To my understanding Route Views and RIS lean on the former category, bgp.tools 
tries (with some degree of success but not total) to remove the obviously stuck 
routes from the view because it has knock on issues for the usefulness of the 
rest of the platform



On 3/3/26 08:13, Hank Nussbacher via NANOG wrote:
> Hi,
> 
> 
> We had F5 announce a /24 on our behalf.  We then asked F5 to withdraw 
> that /24.  Route-views showed the /24 still being announced via an F5 
> path.  F5 claims that route-views is incorrect and the route had been 
> properly withdrawn.  They state that public route collectors 
> (including
> route-views) reflect what their individual collector peers are seeing 
> at a given moment. Due to propagation timing, peer refresh intervals, 
> and collector update cycles, visibility across different monitoring 
> platforms is not always perfectly synchronized in real time.
> 
> 
> Have others seen this type of issues from route-views?
> 
> 
> Thanks,
> 
> Hank
> 
> _______________________________________________
> NANOG mailing list https://lists.nanog.org/archives/list/
> [email protected]/message/GF6SKJK2X3NCOELFTAHZOTRO62DH5G6O/

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