Re: [v6ops] I-D Action: draft-ietf-v6ops-6to4-to-historic-07.txt

[Brian E Carpenter <[e-mail]>]

Hi David,

Thanks for the comments - see below.

On 12/11/2014 08:33, David Farmer wrote:
> On 11/10/14, 23:44 , Brian E Carpenter wrote:
>> This is intended to incorporate the result of today's discussion.
>> Please let the authors know if we got it wrong.
>>
>>     Brian
> 
> I wasn't at the IETF Meeting so I don't know if you have the correct
> result from that discussion.  However, I believe the result is
> consistent with my understanding of the consensus on the v6ops list.
> Further, I support deprecation of Anycast 6to4, and the general take of
> the Draft.
> 
> But, I feel the Draft should also either update or replace RFC6343.
> Minimally, I think it is important for there to be a metadata linkage
> between RFC6343 and the Draft.  I would suggest a formal update to
> Section 4 of RFC6343 substituting the use of Router 6to4 in place of
> Anycast 6to4.

6343 is non-normative, so I'm not sure that we need to formally
update it.  Also I don't agree that we should *encourage* people
to apply the Router 6to4 scenario (which has been essentially
ignored by the market for 13 years). But you are correct that some
of the guidelines in 6343 might be taken as a positive recommendation
to run an anycast relay, so how about adding this:

"The guidelines in Section 4 of [RFC6343] remain valid only for
those who choose to continue operating Anycast 6to4 despite its
deprecation."

> Regardless, Section 4.5 of RFC6343 recommends the use of 192.88.99.1 as
> the IPv4 source address for Return Relay traffic, this no longer seem
> appropriate with the deprecation of 192.88.99.1, the prefix
> 192.88.99.0/24, and Anycast 6to4 in general.  The 6th paragraph of
> Section 4 of the Draft discusses Return Relays and references Section
> 4.5 of RFC6343, I believe the intent is that "content providers might
> choose to continue operating such a relay", but I think the
> recommendation regarding the use of 192.88.99.1 as the IPv4 source
> address of such traffic, contained in Section 4.5 of RFC6343 could be
> confusing and is no longer appropriate.

Why? Setting 192.88.99.1 as a *source* address is orthogonal to whether
it's filtered by the routing system as a destination. It's pretty much
harmless.

> The draft says RFC6890 should be updated to remove "the 6to4 relay
> anycast prefix (192.88.99.0/24)", but RFC6890 doesn't need to be
> updated.  RFC68980 created "Special-Purpose IP Address Registries", no
> update to the RFC is necessary, IANA only needs to update the
> appropriate registry, which is already requested in section 5.  You may
> want to specifically call out the appropriate registry "IPv4
> Special-Purpose Address Registry" in section 5, but there is no need to
> update RFC6890.

Table 10 of 6890 explicitly mentions 192.88.99.0/24, so I think it
does need to be updated. Actually we could do it right here in the
draft by adding "Updates: 6890" and specifying that Table 10 is
deleted. We do need to improve the IANA Considerations wording
on that point, too.

Regards
   Brian