[outages] Major Level3 (CenturyLink) Issues

Vincent Bernat bernat at luffy.cx
Wed Sep 2 19:01:20 UTC 2020

 ❦  2 septembre 2020 16:35 +03, Saku Ytti:

>> I am not buying it. No normal implementation of BGP stays online,
>> replying to heart beat and accepting updates from ebgp peers, yet
>> after 5 hours failed to process withdrawal from customers.
> I can imagine writing BGP implementation like this
>  a) own queue for keepalives, which i always serve first fully
>  b) own queue for update, which i serve second
>  c) own queue for withdraw, which i serve last

Or maybe, graceful restart configured without a timeout on IPv4/IPv6?
The flowspec rule severed the BGP session abruptly, stale routes are
kept due to graceful restart (except flowspec rules), BGP sessions are
reestablished but the flowspec rules is handled before before reaching
EoR and we loop from there.
Make sure your code "does nothing" gracefully.
            - The Elements of Programming Style (Kernighan & Plauger)

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