[address-policy-wg] Summary TLD Anycast Allocation Policy

Dear WG!

I have followed the discussion about the TLD Anycast Allocation Policy
and decided not to quote from the previous posting but to pick up the 
arguments - as I
have understood them - and pointing to the places where I have
tried to address them in my policy draft.

1. Is there a need for anycasting at all ?

I was surprised to see this question on the list.
I think that anycasted nameservers are an accepted standard and there
is no need to discuss pros and cons anymore.


2. /32 vs. /48 V6 prefix - routability aspect

>From a routing table perspective there is no difference if the prefix is
longer or shorter. When asking around which prefix length would have a
good chance to ensure the goal of not beeing filtered I have felt 
consensus
that a /32 has by far the best chances. However I'm considering if it 
wouldn't be best to declare a /32 microallocation block from which RIPE 
will
assign /48 blocks.

3. /32 vs. /48 V6 prefix - address conservation aspect

There is no question that a /32 is quite a big block and that this 
sacrifice
to "ensure" reachability from most network places is worth it.
This question should be raised at regular intervals which is covered by
renewing/adjusting/withdrawing the policy if circumstances have changed.
I felt that there has been consensus within the folks I have
talked to that a /32 is currently a good thing to keep the komplexity
of anycast deployment at a bearable level. However the last disccusion
showed me that a lot of people would prefer to assign /48 from a /32
TLD Anycast Allocation Block.

4. Are the number of assignments under this policy limited?

The policy in its current form implies a limit of one V4 and one V6 block
assignment because as soon as one assigment is made there is no chance
to pass the referenced IANA test to get another assignment.

5. Who gets the address assignment?

The assignment is bound to a TLD nameservice. Therefore the applicant 
would be
a TLD administrator. The TLD administrator can use this assignment either
by himself or hand it to an anycast provider that will operate the anycast
nameservers for him.
I don't think that sharing an assignment between multiple TLDs if they 
outsource
their operation to an anycasting DNS provider should be a must to separate
TLD operations from each other and that the extra address space spent is a 
good
thing keeping in mind the limited number of TLDs where talking about.


Summary:

I hope with my explanation it explains that most of the concerns have been
addressed already. Allocating a /32 prefix to all RIPE TLD anycast 
assignments
should help to address concerns about address space usage and make setting 
up
routing filters easier.

Any comments or suggestions?

Andreas
-- 
DENIC e.G.                 Phone :+49 69 27235 120
Wiesenhuettenplatz 26      Fax   :+49 69 27235 235
D-60329 Frankfurt          Mail  : baess at denic.de
-- 
DENIC e.G.                 Phone :+49 69 27235 120
Wiesenhuettenplatz 26      Fax   :+49 69 27235 235
D-60329 Frankfurt          Mail  : baess at denic.de