The long tail of routers receiving your update doesn’t matter. Once the common transit networks get it, that’s where the rest would dump the traffic to reach you anyway. The only time slow propagation to the edges matters is the first time announcing a prefix after it has been fully withdrawn.
Using the wrong route to get the packet in your general direction still gets you the packet as long as it hits an ISP along the way that got the update.
We could fully drain traffic from a transit provider in <60s with a withdrawal with all of the major providers you get at the internet exchanges. If you weren’t seeing that your upstream ISPs may have penalized you for flapping too much and put in explicit delays.
<60s sounds about right as a general safe estimate. I just mean people should expect 1-2ish orders of magnitude more than <1s from a downed link with internet BGP upstreams in a multihomed situation.
If it were flap suppression/slow peer detection/"the dunce bucket" there wouldn't be a long tail of convergence - it'd just be nothing until all at once. This also isn't something I've only seen on my personal AS alone, it's what I've come to expect in many enterprise cutovers while previously working at a network VAR. The personal AS is however much more carefree to move around to different random providers on a whimthough of course :).
I found some data from an oldish post by benjojo https://blog.benjojo.co.uk/post/speed-of-bgp-network-propaga... which confirm various tirr 1s do propagate updates across their networks very fast (<2ish seconds) while others certainly do not. Notably, Level 3 (now Lumen) is the largest BGP presence by prefix count and was the worst tested in the list - starting to apply at ~20s after to finishing at ~50s after. This was for announce specifically, which should be the clearer case.
Using the wrong route to get the packet in your general direction still gets you the packet as long as it hits an ISP along the way that got the update.
We could fully drain traffic from a transit provider in <60s with a withdrawal with all of the major providers you get at the internet exchanges. If you weren’t seeing that your upstream ISPs may have penalized you for flapping too much and put in explicit delays.