Re: [homenet] PREFIX-DOMAIN in HNCP

[Steven Barth <[e-mail]>]

> I still find the PREFIX-DOMAIN TLV confusing.  Could you please confirm
> that the following is correct:
>
> 1. the PREFIX-DOMAIN TLV can only appear within a DELEGATED-PREFIX TLV;
Correct.

> 2. if a DELEGATED-PREFIX TLV contains no PREFIX-DOMAIN, or if it contains
>    a PREFIX-DOMAIN with Prefix Length = 0 (possibly among other such TLVs),
>    then it MAY be used for assignment;  otherwise, it MUST NOT be used for
>    assignment;
No, -07 currently says that locally generated prefixes (e.g. ULAs) and
those with internet access are "desired" in the sense of
draft-ietf-homenet-prefix-assignment (this is not standard normative language).
Maybe we should ask Pierre what the actual normative translation to that is,
my personal take is that desired means "MUST assign" unless changed by
local policy.

Anyway others aren't currently "desired" by default, i.e. except by policy.
Thinking about that this might be too restrictive since we want to usually just
pass on all information to clients by default. So consider this changed for -08,
to all are desired by default.

I'm currently considering  a new type "explicit" or so which says that you must
only assign prefixes from this is you can actually identify this by (manufacturer
or administrator provided) local policy retaining that functionality. So you can
still have special DPs which are only selectively assigned from.

Also maybe this thing should be renamed to Prefix Policy TLV since this seems
more accurate.


3. if a delegated prefix with non-zero domain is included within a prefix
   with zero domain, it still causes the (longer, smaller) prefix to be
   excluded from prefix assignment according to 6.2.1.

It is intended as: Delegated Prefixes included within other Delegated Prefixes
are ignored, as well as their nested options. I will make this more explicit.


Cheers,

Steven