On Mon, Apr 4, 2022 at 10:41 AM Vasilenko Eduard via NANOG <
nanog@nanog.org> wrote:
240.0.01.1 address is appointed not to the router. It is appointed to Realm.
It is up to the realm owner (ISP to Enterprise) what particular router (or routers) would do translation between realms.
Please forgive me as I work this out in my head for a moment.
If I'm a global network with a single ASN on every populated continent
on the planet, this means I would have a single Realm address; for
the sake of the example, let's suppose I'm ASN 42, so my Realm
address is 240.0.0.42. I have 200+ BGP speaking routers at
exchange points all over the planet where I exchange traffic with
other networks.
In this new model, every border router I have would all use the
same 240.0.0.42 address in the Shaft, and other Realms would
simply hand traffic to the nearest border router of mine, essentially
following a simple Anycast model where the nearest instance of the
Realm address is the one that traffic is handed to, with no way to do
traffic engineering from continent to continent?
Or is there some mechanism whereby different instances of 240.0.0.42
can announce different policies into the Shaft to direct traffic more
appropriately that I'm not understanding from the discussion?
Because if it's one big exercise in enforced Hot Potato Routing with
a single global announcement of your reachability...
...that's gonna fail big-time the first time there's a major undersea
quake in the Strait of Taiwan, which cuts 7/8ths of the trans-pacific
connectivity off, and suddenly you've got the same Realm address
being advertised in the US as in Asia, but with no underlying connectivity
between them.
We who do not learn from history are doomed to repeat it...badly. :(
Matt