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> It gives you a cheap way to preflight what will happen when you make a globally impacting config change. Your "1-minute flap" can propagate and trigger load

by eqvinox 9mo ago

> It gives you a cheap way to preflight what will happen when you make a globally impacting config change. Your "1-minute flap" can propagate and trigger load on every single DFZ BGP router on the planet. That's not cheap. And 1 minute is too short to even propagate across carriers. There are all kinds of timers working to reduce previous point; your update can still be propagating half an hour later. It can also change state for when you do it for real. And worst of all, BGP routes can get stuck. It's rare, but a real problem.

vlovich123 9mo ago
Ok. 5 minutes. The point is clearly there’s route changes happening globally already. It should not be that much extra work to add like 10% more route changes (again - you’d batch the new route advertisements in one cohort rather than updating each individual route back and forth). And stuck routes are a problem but not one this would make worse since those routes would get stuck from normal changes anyway. The propagation problem isn’t real because clearly most route advertisements that handle most of the traffic actually happen quickly. You shouldn’t care about the long tail - you want to minimize the risk of your new route. The old route being present isn’t a problem and the new route disappearing back to the old also shouldn’t be a problem UNLESS the new route was buggy in which case you wanted to rollback anyway. TLDR: these don’t feel like risks unique to advertising and then undoing it given the route publishing already has to be handled anyway AND cloudflare is a major Tier 1 ISP and handles a good chunk of the entire internet’s traffic. This isn’t about a strategy for some random tier 2/3 ISP.
- eqvinox 9mo ago
  > This isn’t about a strategy for some random tier 2/3 ISP. That's not a constraint you mentioned in your original post. > Ok. 5 minutes. The point is clearly there’s route changes happening globally already. It should not be that much extra work to add like 10% more route changes […] I see you haven't had to deal with the operational reality of devices handling things they weren't quite designed for, and/or have been overdue for replacement, and/or were just designed to the limit to begin with. Good for you. But your solution would affect the entire internet. If you're serious, you could try posting your suggestion to the NANOG or RIPE mailing lists. At the very least you'll probably learn a whole new set of expletives and curses… but I'd recommend against it.

by eqvinox 9mo ago

vlovich123 9mo ago

Ok. 5 minutes. The point is clearly there’s route changes happening globally already. It should not be that much extra work to add like 10% more route changes (again - you’d batch the new route advertisements in one cohort rather than updating each individual route back and forth). And stuck routes are a problem but not one this would make worse since those routes would get stuck from normal changes anyway. The propagation problem isn’t real because clearly most route advertisements that handle most of the traffic actually happen quickly. You shouldn’t care about the long tail - you want to minimize the risk of your new route. The old route being present isn’t a problem and the new route disappearing back to the old also shouldn’t be a problem UNLESS the new route was buggy in which case you wanted to rollback anyway. TLDR: these don’t feel like risks unique to advertising and then undoing it given the route publishing already has to be handled anyway AND cloudflare is a major Tier 1 ISP and handles a good chunk of the entire internet’s traffic. This isn’t about a strategy for some random tier 2/3 ISP.

eqvinox 9mo ago
> This isn’t about a strategy for some random tier 2/3 ISP. That's not a constraint you mentioned in your original post. > Ok. 5 minutes. The point is clearly there’s route changes happening globally already. It should not be that much extra work to add like 10% more route changes […] I see you haven't had to deal with the operational reality of devices handling things they weren't quite designed for, and/or have been overdue for replacement, and/or were just designed to the limit to begin with. Good for you. But your solution would affect the entire internet. If you're serious, you could try posting your suggestion to the NANOG or RIPE mailing lists. At the very least you'll probably learn a whole new set of expletives and curses… but I'd recommend against it.