Re: Confirmation to advance: draft-ietf-6man-ipv6only-flag-05

[Mikael Abrahamsson <[e-mail]>]

On Fri, 10 May 2019, 神明達哉 wrote:

>> "   A host that receives only RAs with the flag set to 1 SHOULD NOT
>>     attempt any IPv4 operations, unless it subsequently receives at least
>>     one RA with the flag set to zero.  As soon as such an RA is received,
>>     IPv4 operations MAY be started.
>> "
>
> This text doesn't read to me that "a host SHOULD NOT start IPv4
> operations until it has received an RA with the ipv6only-flag
> cleared".  At least literally, it just talks about the host's behavior
> *after* it receives an RA with ipv6only-flag on.

Some people seems to have read "attempt" in the above text as "should not 
start", meaning it should delay starting IPv4 operations until it knows 
about the status of this flag (the host has no idea about the flag status 
until it has received RAs at attach time).

If we don't want this to happen then the current text in -05 is not clear 
enough on this case. I believe several people have voiced their opinion 
that they would accept the flag being part of the heuristic of deciding 
whether to continue doing DHCPv4 and/or IPv4 LL (or not). The -05 text 
doesn't seem to actually say this, so it should be changed?

-- 
Mikael Abrahamsson    email: [e-mail]