well-known Anycast prefixes

Thu Mar 21 15:59:18 UTC 2019

Hi James,

On 20/03/2019 21:05, James Shank wrote:
> I'm not clear on the use cases, though.  What are the imagined use cases?
> 
> It might make sense to solve 'a method to request hot potato routing'
> as a separate problem.  (Along the lines of Damian's point.)

my personal reason/motivation is this:
Years ago I noticed that my traffic to the "I" DNS root server was
traversing 4 continents. That's from Tanzania, East Africa.
Not having a local instance (back then), we naturally sent the traffic
to an upstream. That upstream happens to be in that club of those who
don't have transit providers (which probably doesn't really matter, but
means a "global" network).

My Theory :
So just because one I-root instance was hosted at a customer (or
customer's customer), that got higher local-pref and now packets take
the long way from Africa via Europe, NorthAmerica to Asia and that
customer in Thailand. While closer I-root instances would obviously be
along the way, just not from a paying customer, "only" from peering.

I don't know whether or not to blame that "carrier" for intentionally(?)
carrying the traffic that far - presumably the $ they got for that from
the I-root host in Thailand was worth it, and not enough customers
complained enough about the latency?

But I think it would be worthwhile to give them an option and produce a
mechanism of knowing what's anycasted.

Maybe (thinking of it) a solution for really well-known prefixes
available at many instances/locations (like DNS root) would be to have
their fixed set of direct transits at all the "global" nodes and
everywhere else to tell peers to not advertise this to upstreams.

Greetings,
Frank