Re: [Idr] WGLC on draft-ietf-idr-as-private-reservation-00

[Brian Dickson <[e-mail]>]

On Wed, Dec 12, 2012 at 5:11 PM, David Farmer <[e-mail]> wrote:

> On 12/12/12 12:52 , Brian Dickson wrote:
>
>> Okay, in as-plain, here goes:
>>
>> 42781900[8-9]? | \
>> 4278190[1-9]?? | \
>> 427819[1-9]??? | \
>> 4278[2-9]????? | \
>> 4279?????? | \
>> 428??????? | \
>>
>
> Just a thought, couldn't you eliminate the rest with the following
> shortcut;
>
> 429???????
>
>
Doh! (<facepalm>).

Good point, good catch, and yes, you are right.

It also makes the one-liner regexp that has the form "42(something)" a lot
simpler (and easier to debug).

Brian



> Yes, it would match 4294967295 which is not part of the range, but it is
> reserved for other reasons, and shouldn't be seen in the wild at all, Big I
> or little i.  And, would match ASNs bigger than 2^32 which can't exist.  So
> unless some implemented there regexp library in a vary weird way, you are
> down to 7 lines.  Yes, its cheating a little, but so what.
>
>
>  429[0-3]?????? | \
>> 4294[0-8]????? | \
>> 42949[0-5]???? | \
>> 429496[0-6]??? | \
>> 4294967[0-1]?? | \
>> 42949672[0-8]? | \
>> 429496729[0-4]
>>
>> In fix-width, and wrapped so one-per-line, and using "hyphen" even for
>> consecutive digits, it lines up nicely (so you can easily verify
>> correctness).
>>
>> Feel free to use the above (and if you like, credit me :-)).
>>
>> Again, not too horrible - 13 terms instead of 5 for as-dot, or 7-8 for
>> current 16-bit.
>>
>
> So with the shortcut above, you are back to more or less the same length
> as the regexp for the original private ASN block.
>
> Throwing some some version of this discussion is as an appendix might not
> be a bad idea, including a regexp for the original private ASN block too.
>  And, just maybe that could help cut down on some of the leaking. I can't
> see how it could possibly make leaking any worse.
>
>
> --
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