Re: IPv6 Netowrk Device Numbering BP

[Owen DeLong <owen () delong com>]

On Nov 1, 2012, at 4:52 PM, Karl Auer <kauer () biplane com au> wrote:

> On Thu, 2012-11-01 at 07:07 -0700, Owen DeLong wrote:
> > I agree with you that we shouldn't introduce partially decimal format,
> but I
> > don't see why you say IPv6 addresses are difficult to parse.
>
> They are not simple to parse, but not particularly difficult either.
>
> > 1.   Tokenize (on : boundaries).
> > 2.   If n(tokens) < 8, expand null token to 9-n tokens.
>
> It's a bit harder than that. You need to deal with the positioning of
> the "::", which may be at the beginning or end. Scope identifiers need
> to be handled. On output, you need to handle the requirements of RFC
> 5952.

Expanding the :: assumed expanding it in place. That's all you need to
do to deal with the positioning of it. It can occur anywhere, not just
at the beginning or end, as in 2620:0:930::200:2 which is, btw, also
equivalent to 2620::930:0:0:0:200:2.

> > You really shouldn't need to parse [mapped addresses] and it's
> perfectly valid
> > to reject them as invalid input.
>
> No, it's not OK to reject them. You can't just say they are invalid,
> they are not.

Yes, it was pointed out to me that for some silly reason passing
understanding, that syntax is supported. It's absurd, but supported.
Sigh

Probably we should deprecate it as it really doesn't make sense to 
use it that way.

Owen