Re: A proposal for draft-ietf-6man-rfc4291bis-07

Le 03/03/2017 à 03:39, David Farmer a écrit :
>
>
> On Thu, Mar 2, 2017 at 8:05 PM, Manfredi, Albert E
> <albert.e.manfredi@boeing.com <mailto:albert.e.manfredi@boeing.com>> wrote:
>
>     From: David Farmer [mailto:farmer@umn.edu <mailto:farmer@umn.edu>]
>
>     >> Brian E Carpenter <brian.e.carpenter@gmail.com
>     <mailto:brian.e.carpenter@gmail.com>> wrote:
>
>     >> Agreed. And I think there are actually two things to say here:
>     >>
>     >> 3.1. Any IPv6-over-foo spec must specify a recommended IID length.
>     >> 3.2. In the absence of such a spec, the recommended IID length is
>     >> 64 bits.
>
>
> How about, IIDs are REQUIRED to be 64 bits unless overridden by an
> IPv6-over-foo spec?
>
>
>     >> Again, that breaks no running code, and it respects the architectural
>     >> statement that prefix_length + IID_length == 128, and the use of CIDR
>     >> routing and variable-length subnet masks.
>     >>
>     >>    Brian
>     >
>     > I'd be fine with that, but others seem to feel otherwise. Lorenzo
>     > and James?
>
>     That's why it's called "consensus." As opposed to unanimity.
>
>     > However, if a provider only delegates a /64, this new text ensures
>     that
>     > prefix could be further subnetted down below /64 using manual
>     config or
>     > possibly DHCPv6.
>
>     Exactly. So, how can we allow RFC 4291 bis to say that 64-bit IIDs
>     are REQUIRED? We can't. That was my original point.
>
>     Bert
>
>
> Because, it doesn't say IIDs are themselves required.  In fact it
> says "at a minimum, a node may consider that unicast addresses
> (including its own) have no internal structure". IIDs are just that
> internal structure of an address, which is by that text is OPTIONAL.
> Therefore, it is only saying if you use an IID it must be 64 bits.
>
> And I'd now suggest it should say, if you use an IID it must be 64 bits
> unless overridden my an IPv6-over-foo spec.

YEs, as long as we are allowed to update RFC2464 with MAY 
other-than-64bit IID.

Alex

>
>
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