[ppml] Proposed Policy: 4-Byte AS Number Policy Proposal

Rich Emmings rich at nic.umass.edu
Wed Dec 14 10:29:14 EST 2005

On Wed, 14 Dec 2005, Owen DeLong wrote:

>I'm afraid I don't understand your issue.  In 4 octet space, we have more
>than 4 Billion potential ASNs.  Reserving 1023 of them doesn't really seem
>to me like it matters.  Remember, it's not 1023 of each 16 bit block, it's
>just 1023 of the first block.  In 32 bit parlance, 0.65520-0.65534 that
>is the current private reservation.
>I don't think we can really justify shrinking that range given wide 
>deployment that already exists.

Ok, trying the simple approach, "4 Byte ASN numbers > 4294836224 and < 
4294967295 are reserved as 4 byte private ASN's.  The existing 2 byte ASN's 
are left as is.  (or use dotted notation if it's of more comfort.)

> I think that play can be done and/or filtered in other ways without requiring
> the creation of an additional block of private ASNs for that purpose.
> Not announce filters that exclude your 4-byte ASN are easy enough to build
> pretty reliably.

Absolutely can be done, the question is, will it be done?  Ref: the weekly 
reports to nanog that include who is leaking addresses and ASN's.  At least 
in that context, they are tagged as invalid.

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