I think, I have found the answer to one of my questions by myself:
GRE-tunneled Anycast with a far remote outer address and a locally scoped
inner anycast address.
Heiner
In einer eMail vom 22.04.2009 00:29:24 Westeuropäische Normalzeit schreibt
HeinerHummel at aol.com:
In einer eMail vom 21.04.2009 23:54:19 Westeuropäische Normalzeit
schreibt bill at herrin.us:
On
Tue, Apr 21, 2009 at 4:00 AM, <HeinerHummel at aol.com>
wrote:
> As I understand Anycast is about delivery to one out of
multiple
> destinations within a given scope.
Hi
Heiner,
I would have said "closest one from the set of valid
destinations,"
but your version is good enough.
More precisely "closest one from the set of valid destinations with
respect to the source,"
> Where is the center point of this scope ? Is it
always the location of the
> source ?
I don't understand the
question. What is a center point wrt routing?
My question is: with anycast do we always understand the above, or could
it also be any particular destination within the scope of an indicated remote
location like a different continent?
What do we understand by Anycast in the future ? Some one must do the
mapping to a specific Unicast address? Is it always the ingress ? Or can't
there be reasonable anycast services which require to send the data to
some far distant anycast server where it will be mapped to
some local unicast addresss ?
> What are the requirements for Anycast in a new
architecture?
Well, that's the crux of the discussion, isn't it?
Anycast and unicast
are identical in every respect in the current
architecture. How do we
bound the unforeseeable consequences if that
isn't true in the new
one?
I'm getting ready to introduce an
anycast route into the table in
order to implement a "continuing
operations" system with three sites
half a world apart. "Continuing
operations" is a fancy phrase for
"disaster recovery," something that
became really popular almost 8
years ago. Once a packet hits any of the
always-running sites, a VPN
takes it back to the site with the servers
flagged "best" for that
particular address, so holistically its unicast
but from the
perspective of the Internet core its anycast from three
distinct
locations.
Would this have any hope of working right in
an architecture that
didn't accommodate anycast? How many such uses are
out there, ready to
impede the deployment of the unwary
plan?
Sorry, I don't understand what you are hereby saying.
Heiner
Regards,
Bill Herrin
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