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

  • From: Robert Bonomi
  • Date: Wed Dec 14 09:35:30 2005

> From [email protected]  Wed Dec 14 04:30:07 2005
> To: [email protected]
> From: [email protected]
> Date: Wed, 14 Dec 2005 10:32:06 +0000
> Subject: [ppml] Fw: ":" - Re: Proposed Policy: 4-Byte AS Number
> 	Policy	Proposal
> > I'm also not thrilled with "2-byte only" and "4-byte only" ASN; there's 
> too
> > much chance of confusion with "2-byte" and "4-byte" ASNs which have a
> > different enough meaning to warrant a better distinction.  I'd prefer
> > something like "legacy" vs. "expanded", "low" vs. "high", etc.
> That's an example of the lack of plain English in the 
> proposal. Why don't we just talk about AS numbers greater
> than 65535 or AS numbers less than 65536?

Because there is more to it than just that.  :)

there is the matter of whether they are represented by 2 bytes, or 4 bytes
_in_transmission_.   '0x00004F4F' is a '4-byte' AS number that has a value
less than 65,536.  It _should_ be treated identically with the 2-byte AS 
number '0x4F4F', as I understand the currently-proposed methodoloty, but 
there is no intrinsic reason why that _must _be the case.  A two-byte AS 
number, and a 4-byte AS number with the SAME numeric value, _are_ 
distinguishable as =different= entities.
> 1. ARIN begin allocating AS numbers greater than 65535
> to those who specifically request them starting on $date.
> 2. On $date ARIN will not allocate AS numbers less than
> 65536 unless a small number is specifically requested.
> 3. On $date, ARIN will no longer make a distinction
> between AS numbers less than 65536 and larger ones.
> Guess what? I said it in plain English so I don't have to 
> define what is an "AS number less than 65536" or an "AS number
> greater than 65535". I also don't have to invent silly new
> notations so that AS2 looks different after the change. 
> A number is a number is a number.

Is it?  <grin>

Do you represent AS 17 in two bytes, or four?  

if you use 2 bytes, do you, "somewhere down the road", change to representing
it with 4 bytes?  or do you deal with 'mixed-length' codes "in perpetuity"?