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

Thanks Andreas for this clear summary. As you asked at the end of your
 message below, I would have one comment and one suggestion :

- comment: One /48 microallocation per TLD under a common
  prefix ( a /32 or shorter per RIR) would ideally meet the goal. The
  "well-known" prefix would be taken into account in BGP filters so
  that /48 get the biggest chance not to be filtered.

- suggestion: While waiting for the "ideal solution" to be
  implemented. The wg should move forward with this proposal and
  allocate one /32 per TLD applying for it. Probably, only a small
  number of TLDs will ask for such allocations before the "ideal
  solution" gets in place. In all cases, the number of requested
  blocks is bounded and there must be no scaling issues since the
  conditions are clearly stated: TLD + Anycast (+ potential problems
  with growing DNS response size due to growing number of NS's and
  glue RR's).

Regards,

Mohsen.

 On 04 Apr, Andreas B/Denic wrote:
 | 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