Telia Not Withdrawing v6 Routes

Mon Nov 16 19:45:59 UTC 2020

See my latest response from this morning. Telia's "Head of Network Engineering & Architecture" confirmed on Twitter this 
was due to a (now-worked-around) bug in JunOS.

https://twitter.com/gustawsson/status/1328298914785730561

Matt

On 11/16/20 2:13 PM, Sabri Berisha wrote:
> ----- On Nov 15, 2020, at 5:58 PM, Matt Corallo nanog at as397444.net wrote:
> 
>> Has anyone else experienced issues where Telia won't withdraw (though will
>> happily accept an overriding) prefixes for the past week, at least?
> 
> I have seen issues like this in a network that I operated. In that particular
> case, it was an internal ipv4 10/8 route which was withdrawn, along with a
> few hundred other routes. The withdrawl was configured on a DC exit router,
> in a Clos network with leaf, spine, and superspine. On the spine layer, I
> observed that BGP withdrawls, although being received, were not processed
> by the control plane.
> 
> Further investigation and working with the TAC of the vendor, revealed that
> on that particular platform, the BGP process would stop process withdrawls
> in a very nasty race condition that was very difficult to reproduce.
> 
> This was the first (and so far only) time in my 20+ years of working with
> BGP that I've observed such a weird bug. Since I operated the entire
> network, it was fairly easy to find the culprit. The why, took some more
> time.
> 
> If I were in your shoes, I'd ping Telia's NOC to see what's going on. I
> would not be surprised if they'd be hitting a similar issue.
> 
> Thanks,
> 
> Sabri
> 